Overview of Focused Ion Beam Technology

Okay, so my name is Roberto Garcia and I'm here at the analytical instrumentation facility. I'm the FIB lab manager and FIB stands for focused ion beam instrument. So I'm going to give you a little lecture on that and a little demonstration on that today. And like I said, you guys have already seen the SEM. So some of the images are going to be very similar because we're going to be collecting secondary electron ions, even when we have the, I'm sorry, secondary electrons, even when we have the ion beam on. And what the difference is between the SEM and the ion beam is that with the ion beam, when we accelerate the... ions towards the sample, it's going to have enough momentum to remove material from the surface. So we can actually remove material. And in some cases, if we want to insert a precursor gas, we can actually deposit material. So originally the FIBs were created as a circuit edit tool. Okay. So if basically you ran a wafer and had a bunch of different, you know, it's a circuits on there and let's say you made a mistake, you connected something that you shouldn't have or you didn't connect something that you forgot to or whatever, you can take the focused ion beam and cut those connections that you don't want and then actually run a connection across the ones that you do want. So ideally the FIB is good for specific site removal of material, deposition. We can also image with it. You'll see some images of secondary electron channeling that's going to show the grain boundaries really well. And then the other main technique or reason that the FIB is used is to make TEM samples. And that's actually a lot of usage for the FIB right now, to make TEM samples. It's very site-specific and you can get a good sample every time. Okay, so this is the fib that we're using today. It's a Thermo Fisher Hydro Plasma Fib. What's nice about it is that we can actually change the different gases or the different ions that we're going to use to remove material. Most of the time we use xenon. Xenon's good because it's nice and heavy. So basically it'll remove a lot of material. Argon is nice because one, you get the, it's basically non-reactive and you get kind of like a smoother finish. And then there's different applications for nitrogen and oxygen, but it does give us that versatility. We can also, what's in here is called a multi-chemistry system where we can deposit different materials. And in this case, we have the choice of platinum, tungsten or carbon. So this is the typical schematic that we have for the FIB. And this is specifically for making TEM samples. You have your SEM column, which is your electron source at the top here. And the main reason you have that is that whenever you turn on the ion beam, you're removing material. So you're damaging the sample or you're changing the sample in some way. So you really want to have an SEM that's not going to damage the instrument at all to locate a feature of interest or the location where you want to take your sample from. and then you can turn on your ion. So you have your electron source, you have your ion source, you have a lift out needle for manipulation so once you actually make your sample you can lift it out, and a gas ingestion system for depositing material on the surface, most of the time for protecting the area of interest and also for being able to glue the sample onto that lift out needle. And then you have basically what we're going to be looking at is the secondary electron images. So this is a bird's eye view or sample's eye view of the chamber. So again we have our ion column. This one in this case is mounted at an angle at 52 degrees. You have your electron column here. You've got your lift out needle, a couple of deposition needles, and then your secondary electron detector. So this is a comparison of the different types of signals that you're going to get within the two instruments, one the SEM and then the ion column. So with the SEM you're familiar with secondary electrons, backstair electrons, and x-rays. Those are going to be the primary signals that you're going to look at. With the ion beam, what we're going to look at is mostly low energy electrons that are created when the ions impact the sample. We don't get high energy or backscatter electrons at all. We do get some neutrals and we do get some other secondary ions. We do have an ion collector in here to look at that signal. However, we really don't use it very often. It's a very poor signal that we get. So most of the time we're going to be using the low energy electrons or secondary electron signals. And we do generate some x-rays, but it's not something that it's not a lot of them. So it's not something that you're going to actually be able to do EDS with. The other difference between the second with the SEM and the ion beam is that the SEM has a very large interaction volume. OK, so it goes in fairly deep. This is a sample of iron and this is a 30 kV SEM. This is a, I'm sorry, it's made with this casino program that you can download. And then also this is another simulation program for ions. You can see that they're very shallow. So we can take advantage of that because with the ions being very shallow, all the interaction is very close to the surface. And you're going to see how the difference appears between the SEM image and then the ion image. So the primary, one of the primary things you use a fit for is for removing material. So basically you bring in the heavy ions, they come in and they're going to splutter material out. Okay, you have this collision cascade and during that cascade, some of these ions will bounce out, but some of them will also get implanted. So that's also an issue that we have to take into account. Here's some examples. So we have basically this very... micro porous ceramic on this metal substrate. Now we can't do this mechanically. If we try to mechanically polish this, you can see that the features on this ceramic are almost on the nano scale. So it's one of those things where if we tried to polish this on a mechanical polishing wheel, we would probably destroy a lot of that surface. Okay. There's a lot of those features. Here's something that... a company here smart material solution is doing they're basically making these nano patterns into this diamond and they're using the oxygen beam oxygen beam tends to work better for the diamond and what they do is once they make this pattern they can then press it into other materials like a glass or ceramic and then transfer that pattern uh here's another example of uh some nano patterning in this case is toughy the wolf uh what we did is we took basically a bitmap image, a grayscale bitmap image, and wherever the pixels are white or bright, so that's 255 value, it's going to dwell the beam for a long time and wherever it's dark or black with a zero value, it's not going to dwell the beam at all. So you get this kind of 3D kind of relief on the surface. This other pillar that you see here on the right, this is actually from a cement. So they wanted to look at the different properties of the different phases in cement, and cement has a lot of different phases. So they wanted to identify one particular phase and actually get the physical properties from it. So what you do is basically mill away a lot of the material and you just get this pillar, and then you take an AFM and then squash it, and that's going to give you some information about the mechanical properties of that particular phase. And here's another example of basically patterning. We've got the NC State Library logo patterned into one of the hairs from one of the librarians. So you could pretty much pattern into just about anything. So diamond, this is a hair. This one on the right here, this is the logo for the NC State Wilson College of Textiles etched into a cross-section of a fiber that they had. So again, we've got our SEM column here, SEM image, typical SEM image, and this is a piece of silicon. So what I'm going to do is I'm just going to tilt up, and you'll notice that in the lower right-hand corner here, I'm going to tilt up so that I'll be perpendicular to the ion. Okay, so I'm going to pause here and then I'm going to go to my ion beam. And you notice here's my currents here that I've got. We always start off with a very light current. Like I said, anytime you turn on the ion beam, you're removing material from the surface. So you're damaging. So that's why we like to image with the SEM first, find an area of interest, and then go ahead and image with the ion. So I'm going to turn this on and it's very light. And you're going to see it's very similar. To the SEM image, again it's low energy electrons that we're collecting. It's a little bit different, I mean we don't have the same kind of contrast that you're seeing to be in the SEM image. But basically you can use this, move around, and I'll go to the fresh area here. And what I'm going to do is I'm going to set up a pattern. So the first thing I'm going to do is I'm just going to make a square pattern. and tell it okay i want a pattern in this area uh i've got to tell it that it's uh silicon that i'm using and let's see we're gonna make this uh 20 by 20 three microns deep and it's telling me it's gonna take 29 hours and that's because it's based off this current here okay so this is a very light current so i'm just going to increase this a little bit more to four nano amps And the first thing I want to do is I'm going to focus on something. So I'm going to make a little spot somewhere. Okay, and I'm going to focus on that spot. I'm focusing Stigmate just like the SEM. Okay, so now I'm just going to tell it to run. We'll just make this one micron deep and we'll let it run. Okay, so now it's rastering the ion beam over just this area here. Okay, and we'll just go ahead and take a snapshot every 15 seconds or so. So what it's going to do, it's going to take that and make that square. And I told it to go in about one micron deep. So it's going to take about four minutes or so to go that deep and I'll probably stop it beforehand. I just want to show you what it's doing. Okay, so there's a coating on top of the silicon here and right now it's probably gone through most of the coating. That's why you're seeing that big contrast change. Okay, and I made this little hole here just to focus on. So the other thing I can do is if I want I can stop this and we can go ahead and we can make other shapes. We can go with a circle pattern. Same thing I'll tell it to go one micron deep and then I'll make another one here but this one I'm going to change the pattern. Let's make this. I'm going to make it a frame. Okay, so I'm going to make it just basically the outer edge. Okay, so we'll go ahead and run that. So again, same thing. It's just running on this little circular area here. and wherever that beam is hitting wherever that pattern says to hit it's going to remove material Okay, let's go to the next. Let's go to the next pattern. And now it's just going on the outer edge. Okay, so it's going to basically make a little hoop. Okay, so those are the different patterns we can make there. The other thing we can do is if we want is we can go and let's move over we'll go to a little bit lighter current let's do 0.3 we can go ahead and load up uh like I said before a bitmap pattern okay so in this case I'm just going to load up an image file Okay, so it's gonna be a 20 by 20. And you guys all know who that is, right? Okay, we're gonna put them right over here. Zoom up a little bit. And now wherever the pixels are bright, the beam is going to dwell for a long time. Wherever it's dark, it's not going to dwell very long. So if I go ahead and start this up, you can kind of see how the image is progressing. And we'll take a snapshot every 15 seconds. And I told it to go about one micron deep. So if I let this, it's going to take a while. So if I let it go, it would go ahead and actually make this kind of relief kind of structure right on the surface of the silicon following that pattern. OK, so those are the different ways we can use removal with the Ion-V. So we'll go ahead and stop here. So the other thing we can do is we can do depositions. Okay, so essentially we take this needle, a hypodermic needle kind of thing that goes in. It's going to be about 100 microns above the surface of the sample. And we can go in and put in a precursor gas. And the gases are typically, if you're going to deposit anything, it's a metal. It's an organometallic precursor. So it's basically a metal with a bunch of organic components. components to it and what happens is when the ion beam hits it, it's going to cleave off all that organic part and deposit that metal. And we use this particularly when we're making TEM samples because we want to protect a certain area. So we have a particular feature or an area of interest. interest that we want to protect or even just the surface and we lay down something heavy like platinum or tungsten just to make sure that we don't damage what is ever underneath that area. Okay so some of the things that you can do with this like I said a lot of this is made for circuit editing so you can make conductive paths or and here's a conductive path and underneath there's actually an insulator that they use as a precursor. This toilet bowl here, it's kind of a tiny toilet bowl. This was just an example of the kind of unique features and tiny features that we can make using deposition and also removal. This is Matsui, he's a very famous guy. He's done a lot with deposition and removal. And here we've got something a little bit more functional. He's created a bridge and in the bottom half here, he's got some springs. All right, so now what we're going to do is we're going to go ahead and deposit. So what I have to do is I have to bring that needle in. So. I'm going to go ahead and insert it and I'm set at a certain point where I know that the needle's not going to hit. You can see it coming in down here and now you're seeing it up here. So you can see it's fairly close. It's about 100 microns above the surface. So now what I want to do is I'm going to tell it what I want is to deposit on the surface. One nanoamp. So I'm going to come over here, I'm going to take a rectangle, I'm going to say okay I want to make that it's yellow now because it's a removal. What I'm going to do is I'm going to say instead of that I want deposition. So we'll do some platinum deposition. Okay so I'll make this 20. Okay so this is about a two minute deposition. So what I'm going to do first is I'm going to start the flow of the platinum and you'll probably hear the pumps and background start to go. And what I'm waiting for is to jump in the vacuum level because I want to make sure that I've got gas flowing in there before I start it up. And we'll go ahead and start. So now again, I've got gas coming in. and the ion beam going over this entire area here. So what will happen is I should start to get this deposition. So it'll build up quite a ways. So a lot of times when we're doing TEM sample preparation we put down about two microns of material of platinum or tungsten just to make sure that we don't damage the area of interest as we thin it down to make TEM samples. So you can see it kind of build up. And again, we don't do anything like making those little toilet seats or any of the other structures. That requires a lot of time. Most of the time, this fib is used for making TPM samples and some patterning by that one company. So you can see this platinum starting to deposit across here. Okay, and it'll go up to about one micron each, one micron deep. So stop that. Okay, I'm gonna retract my needle. Okay, so another neat thing about the ion beam is that you get what's called this secondary electron channeling contrast. Okay. So what tends to happen is if the crystals in a grain are oriented kind of in a loosely or not as dense direction, let's say like a whole wand or something like that, the ion beam is actually going to travel fairly deep into that crystal structure. And then any electrons that are generated might get absorbed in the material, whereas you'll get some from the surface, but very few. And if you have something, a grain that's aligned where you have a more closely packed direction, you're going to have that ion beam interacting a lot more with the atoms in there closer to the surface, and you're going to have more electrons released. So what that does is gives you this contrast that you don't normally see in an SEM, right, with the electrons. You don't get that mechanism. Again, the ions are very surface sensitive. They're just... uh not going in as deep as the secondary electrons as the electrons are so here's an example of a powder metal that we cut and you can see this nice contrast here that you wouldn't normally see with a regular sem so this is a ion image and we're collecting the electrons the low energy electrons that come off of it and we're using by the way we're using the same detector that we would use for the secondary electrons On the right hand side, this is actually an additive manufactured sample. It was probably made from the same powder here. And of course, during the additive manufacturing process, they're heating the material and growing it in a certain direction. And you get this very, you know, mosaic type of grain structure that's very easy to see with the ion channel. Okay, so if you want to get a really good idea of what your grains look like, like or grain size. I mean an ion image will give it to you very quickly. The other thing with channeling is it's going to depend on the orientation of the grain obviously or the crystal in the ground. So this is the same area you can see I've highlighted a feature that's changing contrast as we tilt it from negative 10 degrees to positive 10 degrees. So you see a huge contrast change. Not only in that area, but in everything around it. We're going to go to another area. So what I have in here is a copper grid. that we use for TEM and I just want to show you the way that we can get that image, that channeling. Okay so here's an example of it and we'll see. So with the secondary electrons here, you're really not seeing anything. It's all kind of just dark. It's all an even gray kind of contrast. And I'm going to come over here and we'll start off with our imaging current. And again, you're not seeing much here, right? Because there's probably some contamination, hydrocarbons on the surface. So what I'm going to do is I'm going to quickly change over to a little bit higher current, and that's going to clean off some of those hydrocarbons, and it's also going to give us that channeling contrast. Okay, so now we're cleaning this off a little bit, and if I let it dwell here for long enough, let's go a little bit higher. Okay, now we're starting to see this grain structure start to come in, right? So I'm cleaning off the higher carbons, and I'm also starting to get that ion image. And this is a very high beam current, so now I'm just going to go a little bit lower to get a little bit better resolution. Okay, now you're seeing all the grains, right? I can get a quick idea of what my grain size is, what the grains look like. Okay, so that's something that you don't see. If I stop it here, you'll see a little bit better now because I cleaned it off. But again, it's not really jumping out at you. the secondary electron, right? It's not very clear. So that's a contrast mesmerism that we have with the ions that we don't get with the secondary electrons. So that's another plus for the ion. So like I said, the main reason for this fib is for making TEM samples. So the first thing you got to do is deposit platinum on a region of interest. Then you're going to remove material from either side to create this very thin window. You're going to bring in a needle to attach to that window, and then you're going to cut it away both on the bottom and on the side, okay? Then you're going to lift that off, attach it to a grid, and then you're going to thin it to transparency so that the electron beam from the TEM can go through. So this is basically the simple... process that we go through. We call the first one a hog out where basically we've laid down some platinum and we just use very high current current beams to remove material. So we're all just interested in just making a very thin window. Then once that window is made we come in and attach the manipulator, the needle, and we glue that in place with the deposition needle. Then we're going to pull it out, put it onto a grid, and again we're depositing. on these little green circle and square here to attach that to the grid. Then we'll cut away the needle. So now while it's on there, we can start to thin it down. So we initially start with a little bit heavier beam, higher current, and then as we get closer and closer to making that window thinner, we go smaller and smaller currents. You can see here that this is very transparent and this is at 30 kV. So if it's transparent at 30 kV, it should be okay at 200 kV with the TEMs. So this is an example of a sample that was made for the TEM. You're seeing here the PADF image, which is basically kind of like a high contrast backscatter image. And with the EDS, we can go across here and we can see where all the elements are on each of these lines. Okay, so this is basically a stacking fault in a crystal. So you can see very clearly the atoms here. Okay, so this is something that is very easy to do with the fib. So you get these really nice images, very site specific. Before you had to do this by hand, and it used to take some time, on average. If we have a silicon sample, you can usually get that done. in about two hours okay and like i said it's very site specific so if you had a defect or some type of area that you want to look at you can go right to that area same thing here we're seeing a layered structure you've got the silicon you've got some type of buffer layer and then you've got some crystals growing on top so typically what i would do for uh sdn for a tem image We'll go back to the silicon sample. Silicon is so much easier just because it removed, it wanted single crystal. It removes in a very predictable manner. Since you, with the copper, you've got all these different orientations. Sometimes you get like one grain that's just going to be very difficult to remove while other ones remove very easily. So, here. So if this were my site of interest, I would have deposited a platinum capping layer on there, and then what I would do is I would call up a routine to remove material from either side. Okay, and then this is the pattern that would happen. And what's going to happen is it's basically a clean cross-section. So you're going to see the pattern start here. and as it inches forward so it's going to slowly inch forward so there's a big difference in how you remove material change this so uh what happens is before when we had our patterns we were putting the ion beam all over the place well in this case what's happening is i'm Starting at one end and slowly inching the beam forward. What that's going to do, it's going to create an edge. And what happens is that edge is going to have enhanced removal because we now have a way for the atoms to escape from the more surface, right? It can escape from the edge and also the surface on top. So that enhanced removal lets me remove material a lot faster. So basically we're just going to go through step through. Let's pretend that there's a, we'll pretend that there's kind of like a platinum strip, platinum layer right here. Let's see. So what I'm going to do is I'm going to, this is a very high beam. I don't want to. uh damage the platinum at all so i'm actually off of it a little bit and we're just gonna go ahead and go up to a certain point it'll do this a couple of times and then uh go to the back and then um basically it's gonna just have this little window remaining there okay is there any questions so far Roberto, I was just wondering if you've had any experience with the perovskites in special care in terms of preparation for these more difficult compounds, you know, when they're organic and inorganic. Yeah, they are more difficult because they charge more and that's an issue with, because obviously we're hitting this with the ion beam and we're generating electrons. So there's an issue with that. with a lot of drift. The other thing is I know that with ceramics, particularly oxides, they tend to recommend the oxygen beam, which is okay as long as that oxygen, because remember, we're going to implant material once we, the oxygen is going to implant in the material. So as long as that oxygen implanting is not going to change anything, it's okay to use that. Otherwise, xenon. Xenon will implant a little bit, but of all the different gases we have, that one tends to be the least. But typically oxides, again, remove very slowly too, so it's one of those things where it just takes a little bit longer. If you're doing some type of oxide ceramic, it's probably going to take you anywhere from three to four hours to create a sample for TEM. So in this case, these are halide perovskites and they also have an organic component. And so I'm wondering, is it possible or is there the capability of doing this fibbing at cryogenic temperatures to try and avoid damage? Yeah, we don't have the cryofib here, but there are some cryofibs for that reason. We have done some polymers and some organic materials here. But again, like you said, you have to worry about the heat because there is a significant amount of heat generated. So there's always that issue. Did I change something in the structure? So typically, if we have an organic, we're doing microtome. But sometimes you can't. A lot of times you have an organic structure put on basically spread on top of silicon. In fact, I've got a sample coming in next week. That's the same thing. I've got some type of organic on top of silicon. So we'll do the same thing and hope that we're not. We'll use very light currents, let's put it that way. The light current is the approach that you'd use without the crowdfib, that would be the approach you'd try. Right. Yep, thanks. Hey Roberto, we've been, they've been asking some questions, I've been able to answer a few in the background, but we had a question about substrates and like, does, do substrates affect the use of the fib? I know that, you know, you know, They've brought up sapphire and glass, and obviously those would be really hard to fit themselves, and they would probably charge a lot. But substrate effect from the patterning perspective, other than maybe not seeing what you're doing. Yeah, so if you have any type of charging, what you get is a little bit of drift in the sample. So most of these instruments have drift control, and we have an older fib that has really good drift control. You basically set up a little pattern and say, OK, check for drift every 60 seconds or however long, and it checks that pattern, and if it has moved, it kind of corrects itself. For some reason on the newer instrument, the drift correction does not work. So it's one of those things I just talked to the service engineer and I said, well, we got to get this straightened out because I can't do any type of sapphire or any type of material in here that drifts. But yeah, sapphire takes a long time. Anything on glass, I've just had something on glass recently that also is awful because you've got a lot of drift. We can't do magnetic materials in this fib. And the reason is... The way this is designed is that we're four millimeters, you can see in that image down there, we're four millimeters away from the bottom of the pole piece. Well, that pole piece is essentially a magnetic field. So if we remove magnetic material, it's going to get sucked up into the pole piece. And we've already had issues with that on the Varios, which is not a fib, but people have looked at magnetic particles and those particles tend to get sucked right up that pole. electron column which causes Chuck a lot of headaches. So magnetic material we don't do in here and like I said you can do sapphire you can do stuff that drifts in here but you're probably going to be doing a lot of adjustments yourself because we don't have the software capability right now. We have another question on this one. So when it comes to like drifting, I was wondering like for SEM patterns you have to do like gold coating on the sample. Is that something that you can do here? Yeah you can do that but I know that with sapphire even once you punch with the ion beam you're basically just going to punch through that conductive layer and once you punch through it starts to drift a little bit so it'll look Really nice when you first put it in and maybe start to do a little bit of work, but then as you dwell down deeper, then you start to have issues again. So there's always going to be a little bit of drift with something that's non-conductive. I had a quick question. Sorry, I was dealing with a... laptop that was dying and maybe someone already asked this but for the for the comparing the tm samples i get the hybrid prostate samples are really unstable beam currents you might tend to use other techniques might be better for imaging the grain structure as you showed do you is that i mean i'm sure you still have to go to low beam currents do you think that's more viable or have you ever seen imaging of the Attempts at imaging the grain structure because that was a big topic. That's what we're thinking about with the EBSD to image the grain structure. Yeah, as long as you realize that once you're, when you're imaging it, you're still removing it. You're removing material. So we have some people that, and people do this routinely, where sometimes they even have nanostructures, nanograins, that they can't really get to. polishing, they can't really reveal them very well, the etchings don't work out very well. They'll come into the fib and they'll get some nice images, but they'll kind of polish off one edge and then look at it with the ion beam, but you've got a limited time before you actually start to etch away things preferentially, right? Because some of the grains are going to mill away faster than others. uh but yeah that's a that's a very common thing to do particularly even for uh nanograin material do you do you happen to know has anyone done that on the hybrid crosskites specifically so the high product that's the topic of this whole ru program yeah everyone here is working with that more or less i don't know if anyone's done that lately uh most of us what i've seen mostly has been metals that have been done but obviously if there's uh crystalline orientation differences, obviously, if they're laying in different orientations, I would think that the ion beam would be able to pick that up. Yeah, that's interesting. I mean, maybe that's something someone in the program could be able to try at some point to see how well that works. What would be the required thickness? Because oftentimes, the perovskites are made as a thin film, and by sort of removing that... That, um, those, those, those layers, oftentimes they're in the order of like nanometers and thicknesses. So what, what's the limit of your instrument in terms of seeing those grain structures? Yeah, that's, that's interesting because they, uh, um, if it's a very thin structure, then you probably might mill through it. What you would have to do is go with a very, very light current. And the lightest and also you can change the voltage if you wanted to to to go even slower. The other thing too is to experiment with some of the other gases that we have here. The xenon is going to probably be very destructive but something a little bit lighter like nitrogen or oxygen as long as it's not going to disrupt the crystal structure it may work a little bit better. In fact I know that um We have nitrogen on here, but I was told by Thermo Fisher if we came up with a reason for using nitrogen to let them know because no one uses it. So that might be a good thing to check to see if nitrogen will help out with that. Thank you. Roberto, I had another quick question. I think, you know, if you put in organics or some of these other materials, is there concern about contamination when you're removing this stuff going into the vacuum system? I realize you're removing very small amounts. Yeah. But just wondering if people are concerned about that. No, I mean, we've removed, I mean, with the other quanta, we've removed a lot. I mean, we've been having... We've had that one for years and it's just one of those things the material a lot of times gets removed by the vacuum system or sometimes it will re-deposit onto your sample. The only thing that we really are concerned with is magnetic material because that one can get attracted and go up the electron column and that's going to degrade our signal. Thanks. Roberto, is there any limitations to the metal, the gas injection? Like, is it really just limited to whatever you have? Are there other options? For the gases right now here, yes, we're limited to those four gases. The other thing is that this particular system, one of the reasons that they kind of made this system is when you start removing material, people always want to remove more. So the other fib that we have maxes out at, I believe, 50 nanoamps. You can see this one goes up to 2.5 microamps. Okay, so that's to remove a lot of material at one time. And that's the thing. People want to remove more and more material each time. In fact, right now, they're kind of at a limit with the fib. So what they're doing is they're adding a laser system to the fib. So if you want to remove even more material. you would remove it first with the laser and then you would come in with the fib and remove some of the damage layer from the laser, right? Because the laser is going to heat up a little bit of the surface. So that tends to be kind of like the trend now for people that want to remove a lot of volume. All right. I have a question. Sure. You can hear me. Thank you for your talk. No, no problem. Good. So my question is after you and maybe maybe you said this and I missed it but after you remove the material is the TEM integrated with the system or do you have to physically take it out of this chamber walk it over the to the TEM and and do your imaging over there how does that how does that part work? That's why we have to lift it out and put it onto a grid so once it's on that grid we then take we fin it down onto that grid and once it's on that thinned down, we take it out of the system here, we put it in a sample box, and then they can image it in the TEM whenever they want. Now some systems are designed so that you actually have the sample in a TEM holder and you can put the TEM holder in and mill it while it's on the TEM holder and then just take that straight out and take it over to the TEM. We don't have that system though. And then do you ever, I guess what's the biggest, do you ever... come upon the problem when you get to the TM and realize that the sample is even either missing or it reoriented itself the way it needs to be. I guess you'd see that after the milling part, but I guess what's the biggest challenge that you have? So I've never had that issue. Whenever I made a sample, it's always stuck. Now, realize that the sample is really tiny. At the most, it's about maybe 10 microns wide by about five to six microns tall. So it has very little mass, so you can take that sample and just shake it all around and it's not gonna move, right? But if your tweezer skills are not, you know, optimum, I had some people say that, you know, they've poked the sample or they've crushed the grid up and they can't really get to it. The biggest issue I have sometimes, we tend to leave, I tend to leave the TEM samples on a little bit on the thick side. Because if they're too thick, we can always bring it back here and polish it off within minutes and then take it back. But if it's too thin, you can't add material, right? So I always tell people, if you want to err on the side of caution, make it a little bit thicker if you have to. I do have them checked with the 30 kV beam. As long as it's transparent, that 30 kV, you shouldn't have any issues at 200. But if they do want to thin it down, they can put it back in 15 minutes and it'll be fine. polish it up a little bit more and thin it down and it should be good to go. That makes sense, thanks. No problem. And Roberto, just for fun, do you have the world's tallest or world's smallest house video? Oh, I don't have that. You know, I meant to look it up. If you look up, if you search for nano fib house, that should come up. with basically a tiny little house that people made by fib. It was a combination of doing fib work and also some little micro manipulators to basically build a 3D structure of a house. Okay, so that's kind of like the way things are going, right? You can now make these tiny 3D structures with the fib, with the aid of the fib and some micro manipulators. It's expensive though. I mean, it's really expensive to do that and it's time consuming. Especially if it's in Raleigh. Yeah. This has been a very basic introduction to the focused ion beam instrument. If you want to know a little bit more information, please check out some of our videos on our YouTube link. Also, we offer a course introduction to focused ion beam and applications. probably about once every three to four months. And that you can see on our website. Thank you very much.

And like I said, you guys have already seen the SEM. So some of the images are going to be very similar because we're going to be collecting secondary electron ions, even when we have the, I'm sorry, secondary electrons, even when we have the ion beam on. And what the difference is between the SEM and the ion beam is that with the ion beam, when we accelerate the... ions towards the sample, it's going to have enough momentum to remove material from the surface. So we can actually remove material.

And in some cases, if we want to insert a precursor gas, we can actually deposit material. So originally the FIBs were created as a circuit edit tool. Okay. So if basically you ran a wafer and had a bunch of different, you know, it's a circuits on there and let's say you made a mistake, you connected something that you shouldn't have or you didn't connect something that you forgot to or whatever, you can take the focused ion beam and cut those connections that you don't want and then actually run a connection across the ones that you do want. So ideally the FIB is good for specific site removal of material, deposition.

We can also image with it. You'll see some images of secondary electron channeling that's going to show the grain boundaries really well. And then the other main technique or reason that the FIB is used is to make TEM samples.

And that's actually a lot of usage for the FIB right now, to make TEM samples. It's very site-specific and you can get a good sample every time. Okay, so this is the fib that we're using today. It's a Thermo Fisher Hydro Plasma Fib.

What's nice about it is that we can actually change the different gases or the different ions that we're going to use to remove material. Most of the time we use xenon. Xenon's good because it's nice and heavy.

So basically it'll remove a lot of material. Argon is nice because one, you get the, it's basically non-reactive and you get kind of like a smoother finish. And then there's different applications for nitrogen and oxygen, but it does give us that versatility.

We can also, what's in here is called a multi-chemistry system where we can deposit different materials. And in this case, we have the choice of platinum, tungsten or carbon. So this is the typical schematic that we have for the FIB. And this is specifically for making TEM samples. You have your SEM column, which is your electron source at the top here.

And the main reason you have that is that whenever you turn on the ion beam, you're removing material. So you're damaging the sample or you're changing the sample in some way. So you really want to have an SEM that's not going to damage the instrument at all to locate a feature of interest or the location where you want to take your sample from.

and then you can turn on your ion. So you have your electron source, you have your ion source, you have a lift out needle for manipulation so once you actually make your sample you can lift it out, and a gas ingestion system for depositing material on the surface, most of the time for protecting the area of interest and also for being able to glue the sample onto that lift out needle. And then you have basically what we're going to be looking at is the secondary electron images.

So this is a bird's eye view or sample's eye view of the chamber. So again we have our ion column. This one in this case is mounted at an angle at 52 degrees.

You have your electron column here. You've got your lift out needle, a couple of deposition needles, and then your secondary electron detector. So this is a comparison of the different types of signals that you're going to get within the two instruments, one the SEM and then the ion column. So with the SEM you're familiar with secondary electrons, backstair electrons, and x-rays.

Those are going to be the primary signals that you're going to look at. With the ion beam, what we're going to look at is mostly low energy electrons that are created when the ions impact the sample. We don't get high energy or backscatter electrons at all. We do get some neutrals and we do get some other secondary ions. We do have an ion collector in here to look at that signal.

However, we really don't use it very often. It's a very poor signal that we get. So most of the time we're going to be using the low energy electrons or secondary electron signals. And we do generate some x-rays, but it's not something that it's not a lot of them.

So it's not something that you're going to actually be able to do EDS with. The other difference between the second with the SEM and the ion beam is that the SEM has a very large interaction volume. OK, so it goes in fairly deep. This is a sample of iron and this is a 30 kV SEM. This is a, I'm sorry, it's made with this casino program that you can download.

And then also this is another simulation program for ions. You can see that they're very shallow. So we can take advantage of that because with the ions being very shallow, all the interaction is very close to the surface.

And you're going to see how the difference appears between the SEM image and then the ion image. So the primary, one of the primary things you use a fit for is for removing material. So basically you bring in the heavy ions, they come in and they're going to splutter material out.

Okay, you have this collision cascade and during that cascade, some of these ions will bounce out, but some of them will also get implanted. So that's also an issue that we have to take into account. Here's some examples.

So we have basically this very... micro porous ceramic on this metal substrate. Now we can't do this mechanically.

If we try to mechanically polish this, you can see that the features on this ceramic are almost on the nano scale. So it's one of those things where if we tried to polish this on a mechanical polishing wheel, we would probably destroy a lot of that surface. Okay. There's a lot of those features. Here's something that...

a company here smart material solution is doing they're basically making these nano patterns into this diamond and they're using the oxygen beam oxygen beam tends to work better for the diamond and what they do is once they make this pattern they can then press it into other materials like a glass or ceramic and then transfer that pattern uh here's another example of uh some nano patterning in this case is toughy the wolf uh what we did is we took basically a bitmap image, a grayscale bitmap image, and wherever the pixels are white or bright, so that's 255 value, it's going to dwell the beam for a long time and wherever it's dark or black with a zero value, it's not going to dwell the beam at all. So you get this kind of 3D kind of relief on the surface. This other pillar that you see here on the right, this is actually from a cement.

So they wanted to look at the different properties of the different phases in cement, and cement has a lot of different phases. So they wanted to identify one particular phase and actually get the physical properties from it. So what you do is basically mill away a lot of the material and you just get this pillar, and then you take an AFM and then squash it, and that's going to give you some information about the mechanical properties of that particular phase.

And here's another example of basically patterning. We've got the NC State Library logo patterned into one of the hairs from one of the librarians. So you could pretty much pattern into just about anything.

So diamond, this is a hair. This one on the right here, this is the logo for the NC State Wilson College of Textiles etched into a cross-section of a fiber that they had. So again, we've got our SEM column here, SEM image, typical SEM image, and this is a piece of silicon.

So what I'm going to do is I'm just going to tilt up, and you'll notice that in the lower right-hand corner here, I'm going to tilt up so that I'll be perpendicular to the ion. Okay, so I'm going to pause here and then I'm going to go to my ion beam. And you notice here's my currents here that I've got. We always start off with a very light current. Like I said, anytime you turn on the ion beam, you're removing material from the surface.

So you're damaging. So that's why we like to image with the SEM first, find an area of interest, and then go ahead and image with the ion. So I'm going to turn this on and it's very light. And you're going to see it's very similar.

To the SEM image, again it's low energy electrons that we're collecting. It's a little bit different, I mean we don't have the same kind of contrast that you're seeing to be in the SEM image. But basically you can use this, move around, and I'll go to the fresh area here.

And what I'm going to do is I'm going to set up a pattern. So the first thing I'm going to do is I'm just going to make a square pattern. and tell it okay i want a pattern in this area uh i've got to tell it that it's uh silicon that i'm using and let's see we're gonna make this uh 20 by 20 three microns deep and it's telling me it's gonna take 29 hours and that's because it's based off this current here okay so this is a very light current so i'm just going to increase this a little bit more to four nano amps And the first thing I want to do is I'm going to focus on something.

So I'm going to make a little spot somewhere. Okay, and I'm going to focus on that spot. I'm focusing Stigmate just like the SEM. Okay, so now I'm just going to tell it to run.

We'll just make this one micron deep and we'll let it run. Okay, so now it's rastering the ion beam over just this area here. Okay, and we'll just go ahead and take a snapshot every 15 seconds or so. So what it's going to do, it's going to take that and make that square. And I told it to go in about one micron deep.

So it's going to take about four minutes or so to go that deep and I'll probably stop it beforehand. I just want to show you what it's doing. Okay, so there's a coating on top of the silicon here and right now it's probably gone through most of the coating.

That's why you're seeing that big contrast change. Okay, and I made this little hole here just to focus on. So the other thing I can do is if I want I can stop this and we can go ahead and we can make other shapes. We can go with a circle pattern. Same thing I'll tell it to go one micron deep and then I'll make another one here but this one I'm going to change the pattern.

Let's make this. I'm going to make it a frame. Okay, so I'm going to make it just basically the outer edge.

Okay, so we'll go ahead and run that. So again, same thing. It's just running on this little circular area here. and wherever that beam is hitting wherever that pattern says to hit it's going to remove material Okay, let's go to the next.

Let's go to the next pattern. And now it's just going on the outer edge. Okay, so it's going to basically make a little hoop.

Okay, so those are the different patterns we can make there. The other thing we can do is if we want is we can go and let's move over we'll go to a little bit lighter current let's do 0.3 we can go ahead and load up uh like I said before a bitmap pattern okay so in this case I'm just going to load up an image file Okay, so it's gonna be a 20 by 20. And you guys all know who that is, right? Okay, we're gonna put them right over here. Zoom up a little bit. And now wherever the pixels are bright, the beam is going to dwell for a long time.

Wherever it's dark, it's not going to dwell very long. So if I go ahead and start this up, you can kind of see how the image is progressing. And we'll take a snapshot every 15 seconds.

And I told it to go about one micron deep. So if I let this, it's going to take a while. So if I let it go, it would go ahead and actually make this kind of relief kind of structure right on the surface of the silicon following that pattern. OK, so those are the different ways we can use removal with the Ion-V.

So we'll go ahead and stop here. So the other thing we can do is we can do depositions. Okay, so essentially we take this needle, a hypodermic needle kind of thing that goes in.

It's going to be about 100 microns above the surface of the sample. And we can go in and put in a precursor gas. And the gases are typically, if you're going to deposit anything, it's a metal. It's an organometallic precursor. So it's basically a metal with a bunch of organic components.

components to it and what happens is when the ion beam hits it, it's going to cleave off all that organic part and deposit that metal. And we use this particularly when we're making TEM samples because we want to protect a certain area. So we have a particular feature or an area of interest. interest that we want to protect or even just the surface and we lay down something heavy like platinum or tungsten just to make sure that we don't damage what is ever underneath that area. Okay so some of the things that you can do with this like I said a lot of this is made for circuit editing so you can make conductive paths or and here's a conductive path and underneath there's actually an insulator that they use as a precursor.

This toilet bowl here, it's kind of a tiny toilet bowl. This was just an example of the kind of unique features and tiny features that we can make using deposition and also removal. This is Matsui, he's a very famous guy.

He's done a lot with deposition and removal. And here we've got something a little bit more functional. He's created a bridge and in the bottom half here, he's got some springs.

All right, so now what we're going to do is we're going to go ahead and deposit. So what I have to do is I have to bring that needle in. So.

I'm going to go ahead and insert it and I'm set at a certain point where I know that the needle's not going to hit. You can see it coming in down here and now you're seeing it up here. So you can see it's fairly close. It's about 100 microns above the surface.

So now what I want to do is I'm going to tell it what I want is to deposit on the surface. One nanoamp. So I'm going to come over here, I'm going to take a rectangle, I'm going to say okay I want to make that it's yellow now because it's a removal. What I'm going to do is I'm going to say instead of that I want deposition. So we'll do some platinum deposition.

Okay so I'll make this 20. Okay so this is about a two minute deposition. So what I'm going to do first is I'm going to start the flow of the platinum and you'll probably hear the pumps and background start to go. And what I'm waiting for is to jump in the vacuum level because I want to make sure that I've got gas flowing in there before I start it up.

And we'll go ahead and start. So now again, I've got gas coming in. and the ion beam going over this entire area here. So what will happen is I should start to get this deposition. So it'll build up quite a ways.

So a lot of times when we're doing TEM sample preparation we put down about two microns of material of platinum or tungsten just to make sure that we don't damage the area of interest as we thin it down to make TEM samples. So you can see it kind of build up. And again, we don't do anything like making those little toilet seats or any of the other structures.

That requires a lot of time. Most of the time, this fib is used for making TPM samples and some patterning by that one company. So you can see this platinum starting to deposit across here.

Okay, and it'll go up to about one micron each, one micron deep. So stop that. Okay, I'm gonna retract my needle. Okay, so another neat thing about the ion beam is that you get what's called this secondary electron channeling contrast. Okay.

So what tends to happen is if the crystals in a grain are oriented kind of in a loosely or not as dense direction, let's say like a whole wand or something like that, the ion beam is actually going to travel fairly deep into that crystal structure. And then any electrons that are generated might get absorbed in the material, whereas you'll get some from the surface, but very few. And if you have something, a grain that's aligned where you have a more closely packed direction, you're going to have that ion beam interacting a lot more with the atoms in there closer to the surface, and you're going to have more electrons released.

So what that does is gives you this contrast that you don't normally see in an SEM, right, with the electrons. You don't get that mechanism. Again, the ions are very surface sensitive.

They're just... uh not going in as deep as the secondary electrons as the electrons are so here's an example of a powder metal that we cut and you can see this nice contrast here that you wouldn't normally see with a regular sem so this is a ion image and we're collecting the electrons the low energy electrons that come off of it and we're using by the way we're using the same detector that we would use for the secondary electrons On the right hand side, this is actually an additive manufactured sample. It was probably made from the same powder here.

And of course, during the additive manufacturing process, they're heating the material and growing it in a certain direction. And you get this very, you know, mosaic type of grain structure that's very easy to see with the ion channel. Okay, so if you want to get a really good idea of what your grains look like, like or grain size. I mean an ion image will give it to you very quickly.

The other thing with channeling is it's going to depend on the orientation of the grain obviously or the crystal in the ground. So this is the same area you can see I've highlighted a feature that's changing contrast as we tilt it from negative 10 degrees to positive 10 degrees. So you see a huge contrast change.

Not only in that area, but in everything around it. We're going to go to another area. So what I have in here is a copper grid.

that we use for TEM and I just want to show you the way that we can get that image, that channeling. Okay so here's an example of it and we'll see. So with the secondary electrons here, you're really not seeing anything. It's all kind of just dark. It's all an even gray kind of contrast.

And I'm going to come over here and we'll start off with our imaging current. And again, you're not seeing much here, right? Because there's probably some contamination, hydrocarbons on the surface.

So what I'm going to do is I'm going to quickly change over to a little bit higher current, and that's going to clean off some of those hydrocarbons, and it's also going to give us that channeling contrast. Okay, so now we're cleaning this off a little bit, and if I let it dwell here for long enough, let's go a little bit higher. Okay, now we're starting to see this grain structure start to come in, right?

So I'm cleaning off the higher carbons, and I'm also starting to get that ion image. And this is a very high beam current, so now I'm just going to go a little bit lower to get a little bit better resolution. Okay, now you're seeing all the grains, right? I can get a quick idea of what my grain size is, what the grains look like. Okay, so that's something that you don't see.

If I stop it here, you'll see a little bit better now because I cleaned it off. But again, it's not really jumping out at you. the secondary electron, right? It's not very clear. So that's a contrast mesmerism that we have with the ions that we don't get with the secondary electrons.

So that's another plus for the ion. So like I said, the main reason for this fib is for making TEM samples. So the first thing you got to do is deposit platinum on a region of interest.

Then you're going to remove material from either side to create this very thin window. You're going to bring in a needle to attach to that window, and then you're going to cut it away both on the bottom and on the side, okay? Then you're going to lift that off, attach it to a grid, and then you're going to thin it to transparency so that the electron beam from the TEM can go through. So this is basically the simple... process that we go through.

We call the first one a hog out where basically we've laid down some platinum and we just use very high current current beams to remove material. So we're all just interested in just making a very thin window. Then once that window is made we come in and attach the manipulator, the needle, and we glue that in place with the deposition needle.

Then we're going to pull it out, put it onto a grid, and again we're depositing. on these little green circle and square here to attach that to the grid. Then we'll cut away the needle. So now while it's on there, we can start to thin it down. So we initially start with a little bit heavier beam, higher current, and then as we get closer and closer to making that window thinner, we go smaller and smaller currents.

You can see here that this is very transparent and this is at 30 kV. So if it's transparent at 30 kV, it should be okay at 200 kV with the TEMs. So this is an example of a sample that was made for the TEM.

You're seeing here the PADF image, which is basically kind of like a high contrast backscatter image. And with the EDS, we can go across here and we can see where all the elements are on each of these lines. Okay, so this is basically a stacking fault in a crystal. So you can see very clearly the atoms here.

Okay, so this is something that is very easy to do with the fib. So you get these really nice images, very site specific. Before you had to do this by hand, and it used to take some time, on average.

If we have a silicon sample, you can usually get that done. in about two hours okay and like i said it's very site specific so if you had a defect or some type of area that you want to look at you can go right to that area same thing here we're seeing a layered structure you've got the silicon you've got some type of buffer layer and then you've got some crystals growing on top so typically what i would do for uh sdn for a tem image We'll go back to the silicon sample. Silicon is so much easier just because it removed, it wanted single crystal.

It removes in a very predictable manner. Since you, with the copper, you've got all these different orientations. Sometimes you get like one grain that's just going to be very difficult to remove while other ones remove very easily.

So, here. So if this were my site of interest, I would have deposited a platinum capping layer on there, and then what I would do is I would call up a routine to remove material from either side. Okay, and then this is the pattern that would happen.

And what's going to happen is it's basically a clean cross-section. So you're going to see the pattern start here. and as it inches forward so it's going to slowly inch forward so there's a big difference in how you remove material change this so uh what happens is before when we had our patterns we were putting the ion beam all over the place well in this case what's happening is i'm Starting at one end and slowly inching the beam forward.

What that's going to do, it's going to create an edge. And what happens is that edge is going to have enhanced removal because we now have a way for the atoms to escape from the more surface, right? It can escape from the edge and also the surface on top.

So that enhanced removal lets me remove material a lot faster. So basically we're just going to go through step through. Let's pretend that there's a, we'll pretend that there's kind of like a platinum strip, platinum layer right here.

Let's see. So what I'm going to do is I'm going to, this is a very high beam. I don't want to. uh damage the platinum at all so i'm actually off of it a little bit and we're just gonna go ahead and go up to a certain point it'll do this a couple of times and then uh go to the back and then um basically it's gonna just have this little window remaining there okay is there any questions so far Roberto, I was just wondering if you've had any experience with the perovskites in special care in terms of preparation for these more difficult compounds, you know, when they're organic and inorganic.

Yeah, they are more difficult because they charge more and that's an issue with, because obviously we're hitting this with the ion beam and we're generating electrons. So there's an issue with that. with a lot of drift. The other thing is I know that with ceramics, particularly oxides, they tend to recommend the oxygen beam, which is okay as long as that oxygen, because remember, we're going to implant material once we, the oxygen is going to implant in the material. So as long as that oxygen implanting is not going to change anything, it's okay to use that.

Otherwise, xenon. Xenon will implant a little bit, but of all the different gases we have, that one tends to be the least. But typically oxides, again, remove very slowly too, so it's one of those things where it just takes a little bit longer.

If you're doing some type of oxide ceramic, it's probably going to take you anywhere from three to four hours to create a sample for TEM. So in this case, these are halide perovskites and they also have an organic component. And so I'm wondering, is it possible or is there the capability of doing this fibbing at cryogenic temperatures to try and avoid damage?

Yeah, we don't have the cryofib here, but there are some cryofibs for that reason. We have done some polymers and some organic materials here. But again, like you said, you have to worry about the heat because there is a significant amount of heat generated. So there's always that issue. Did I change something in the structure?

So typically, if we have an organic, we're doing microtome. But sometimes you can't. A lot of times you have an organic structure put on basically spread on top of silicon. In fact, I've got a sample coming in next week.

That's the same thing. I've got some type of organic on top of silicon. So we'll do the same thing and hope that we're not.

We'll use very light currents, let's put it that way. The light current is the approach that you'd use without the crowdfib, that would be the approach you'd try. Right.

Yep, thanks. Hey Roberto, we've been, they've been asking some questions, I've been able to answer a few in the background, but we had a question about substrates and like, does, do substrates affect the use of the fib? I know that, you know, you know, They've brought up sapphire and glass, and obviously those would be really hard to fit themselves, and they would probably charge a lot. But substrate effect from the patterning perspective, other than maybe not seeing what you're doing. Yeah, so if you have any type of charging, what you get is a little bit of drift in the sample.

So most of these instruments have drift control, and we have an older fib that has really good drift control. You basically set up a little pattern and say, OK, check for drift every 60 seconds or however long, and it checks that pattern, and if it has moved, it kind of corrects itself. For some reason on the newer instrument, the drift correction does not work.

So it's one of those things I just talked to the service engineer and I said, well, we got to get this straightened out because I can't do any type of sapphire or any type of material in here that drifts. But yeah, sapphire takes a long time. Anything on glass, I've just had something on glass recently that also is awful because you've got a lot of drift.

We can't do magnetic materials in this fib. And the reason is... The way this is designed is that we're four millimeters, you can see in that image down there, we're four millimeters away from the bottom of the pole piece. Well, that pole piece is essentially a magnetic field. So if we remove magnetic material, it's going to get sucked up into the pole piece.

And we've already had issues with that on the Varios, which is not a fib, but people have looked at magnetic particles and those particles tend to get sucked right up that pole. electron column which causes Chuck a lot of headaches. So magnetic material we don't do in here and like I said you can do sapphire you can do stuff that drifts in here but you're probably going to be doing a lot of adjustments yourself because we don't have the software capability right now.

We have another question on this one. So when it comes to like drifting, I was wondering like for SEM patterns you have to do like gold coating on the sample. Is that something that you can do here? Yeah you can do that but I know that with sapphire even once you punch with the ion beam you're basically just going to punch through that conductive layer and once you punch through it starts to drift a little bit so it'll look Really nice when you first put it in and maybe start to do a little bit of work, but then as you dwell down deeper, then you start to have issues again.

So there's always going to be a little bit of drift with something that's non-conductive. I had a quick question. Sorry, I was dealing with a...

laptop that was dying and maybe someone already asked this but for the for the comparing the tm samples i get the hybrid prostate samples are really unstable beam currents you might tend to use other techniques might be better for imaging the grain structure as you showed do you is that i mean i'm sure you still have to go to low beam currents do you think that's more viable or have you ever seen imaging of the Attempts at imaging the grain structure because that was a big topic. That's what we're thinking about with the EBSD to image the grain structure. Yeah, as long as you realize that once you're, when you're imaging it, you're still removing it.

You're removing material. So we have some people that, and people do this routinely, where sometimes they even have nanostructures, nanograins, that they can't really get to. polishing, they can't really reveal them very well, the etchings don't work out very well.

They'll come into the fib and they'll get some nice images, but they'll kind of polish off one edge and then look at it with the ion beam, but you've got a limited time before you actually start to etch away things preferentially, right? Because some of the grains are going to mill away faster than others. uh but yeah that's a that's a very common thing to do particularly even for uh nanograin material do you do you happen to know has anyone done that on the hybrid crosskites specifically so the high product that's the topic of this whole ru program yeah everyone here is working with that more or less i don't know if anyone's done that lately uh most of us what i've seen mostly has been metals that have been done but obviously if there's uh crystalline orientation differences, obviously, if they're laying in different orientations, I would think that the ion beam would be able to pick that up.

Yeah, that's interesting. I mean, maybe that's something someone in the program could be able to try at some point to see how well that works. What would be the required thickness?

Because oftentimes, the perovskites are made as a thin film, and by sort of removing that... That, um, those, those, those layers, oftentimes they're in the order of like nanometers and thicknesses. So what, what's the limit of your instrument in terms of seeing those grain structures?

Yeah, that's, that's interesting because they, uh, um, if it's a very thin structure, then you probably might mill through it. What you would have to do is go with a very, very light current. And the lightest and also you can change the voltage if you wanted to to to go even slower. The other thing too is to experiment with some of the other gases that we have here. The xenon is going to probably be very destructive but something a little bit lighter like nitrogen or oxygen as long as it's not going to disrupt the crystal structure it may work a little bit better.

In fact I know that um We have nitrogen on here, but I was told by Thermo Fisher if we came up with a reason for using nitrogen to let them know because no one uses it. So that might be a good thing to check to see if nitrogen will help out with that. Thank you. Roberto, I had another quick question.

I think, you know, if you put in organics or some of these other materials, is there concern about contamination when you're removing this stuff going into the vacuum system? I realize you're removing very small amounts. Yeah. But just wondering if people are concerned about that. No, I mean, we've removed, I mean, with the other quanta, we've removed a lot.

I mean, we've been having... We've had that one for years and it's just one of those things the material a lot of times gets removed by the vacuum system or sometimes it will re-deposit onto your sample. The only thing that we really are concerned with is magnetic material because that one can get attracted and go up the electron column and that's going to degrade our signal. Thanks. Roberto, is there any limitations to the metal, the gas injection?

Like, is it really just limited to whatever you have? Are there other options? For the gases right now here, yes, we're limited to those four gases.

The other thing is that this particular system, one of the reasons that they kind of made this system is when you start removing material, people always want to remove more. So the other fib that we have maxes out at, I believe, 50 nanoamps. You can see this one goes up to 2.5 microamps.

Okay, so that's to remove a lot of material at one time. And that's the thing. People want to remove more and more material each time. In fact, right now, they're kind of at a limit with the fib. So what they're doing is they're adding a laser system to the fib.

So if you want to remove even more material. you would remove it first with the laser and then you would come in with the fib and remove some of the damage layer from the laser, right? Because the laser is going to heat up a little bit of the surface. So that tends to be kind of like the trend now for people that want to remove a lot of volume.

All right. I have a question. Sure. You can hear me.

Thank you for your talk. No, no problem. Good.

So my question is after you and maybe maybe you said this and I missed it but after you remove the material is the TEM integrated with the system or do you have to physically take it out of this chamber walk it over the to the TEM and and do your imaging over there how does that how does that part work? That's why we have to lift it out and put it onto a grid so once it's on that grid we then take we fin it down onto that grid and once it's on that thinned down, we take it out of the system here, we put it in a sample box, and then they can image it in the TEM whenever they want. Now some systems are designed so that you actually have the sample in a TEM holder and you can put the TEM holder in and mill it while it's on the TEM holder and then just take that straight out and take it over to the TEM. We don't have that system though. And then do you ever, I guess what's the biggest, do you ever...

come upon the problem when you get to the TM and realize that the sample is even either missing or it reoriented itself the way it needs to be. I guess you'd see that after the milling part, but I guess what's the biggest challenge that you have? So I've never had that issue.

Whenever I made a sample, it's always stuck. Now, realize that the sample is really tiny. At the most, it's about maybe 10 microns wide by about five to six microns tall. So it has very little mass, so you can take that sample and just shake it all around and it's not gonna move, right?

But if your tweezer skills are not, you know, optimum, I had some people say that, you know, they've poked the sample or they've crushed the grid up and they can't really get to it. The biggest issue I have sometimes, we tend to leave, I tend to leave the TEM samples on a little bit on the thick side. Because if they're too thick, we can always bring it back here and polish it off within minutes and then take it back.

But if it's too thin, you can't add material, right? So I always tell people, if you want to err on the side of caution, make it a little bit thicker if you have to. I do have them checked with the 30 kV beam.

As long as it's transparent, that 30 kV, you shouldn't have any issues at 200. But if they do want to thin it down, they can put it back in 15 minutes and it'll be fine. polish it up a little bit more and thin it down and it should be good to go. That makes sense, thanks.

No problem. And Roberto, just for fun, do you have the world's tallest or world's smallest house video? Oh, I don't have that. You know, I meant to look it up.

If you look up, if you search for nano fib house, that should come up. with basically a tiny little house that people made by fib. It was a combination of doing fib work and also some little micro manipulators to basically build a 3D structure of a house.

Okay, so that's kind of like the way things are going, right? You can now make these tiny 3D structures with the fib, with the aid of the fib and some micro manipulators. It's expensive though. I mean, it's really expensive to do that and it's time consuming. Especially if it's in Raleigh.

Yeah. This has been a very basic introduction to the focused ion beam instrument. If you want to know a little bit more information, please check out some of our videos on our YouTube link. Also, we offer a course introduction to focused ion beam and applications. probably about once every three to four months.

And that you can see on our website. Thank you very much.

Transcript for:Overview of Focused Ion Beam Technology

Transcript for:
Overview of Focused Ion Beam Technology