Focused Ion Beam Instrument (FIB) Lecture Notes

Introduction

• Presenter: Roberto Garcia, FIB Lab Manager at Analytical Instrumentation Facility.
• Overview of FIB and its functionalities.

What is FIB?

• Focused Ion Beam (FIB) is an instrument that uses an ion beam to manipulate materials on a micro and nano scale.
• Initially developed for circuit editing:
  • Used to cut connections in circuit designs on wafers.
  • Allows specific site removal of material and material deposition.

Differences Between SEM and FIB

• Scanning Electron Microscope (SEM):
  • Collects secondary electrons, backscattered electrons, and X-rays.
  • Has a large interaction volume, penetrating deeper into samples.
• FIB:
  • Primarily collects low energy electrons generated when ions impact the sample.
  • Produces shallow interaction volumes, allowing for surface-specific imaging and material removal.

FIB Instrument Details

• Model: Thermo Fisher Hydro Plasma FIB.
• Ion sources used:
  • Xenon: Heavy, effective for material removal.
  • Argon: Non-reactive, provides smoother finishes.
  • Nitrogen and Oxygen: Used for specific applications.
• Multi-chemistry system: allows for deposition of materials such as platinum, tungsten, or carbon.

FIB Components:

• SEM Column: Electron source to locate areas of interest without damaging samples.
• Ion Source: For material removal or deposition.
• Lift-out Needle: For manipulating and lifting samples post-preparation.
• Gas Ingestion System: For depositing protective materials.

Imaging Techniques

• Secondary electron images are used to visualize grain boundaries.
• FIB can create high-quality Transmission Electron Microscopy (TEM) samples, offering site-specific preparation.

Applications of FIB

• Creating TEM samples:
  • Thick samples thinned down to transparency for TEM imaging.
  • Process includes depositing layers of metal to protect areas during milling.
• Nano-patterning:
  • Create features on materials (e.g., diamond) using bitmap images.
• Removing materials from microstructures while preserving smaller features not possible with mechanical polishing.

Demonstration

• Live demonstration of FIB operation:
  • Started with imaging using SEM to identify areas of interest.
  • Transitioned to FIB for material removal and pattern creation.
  • Showed various patterns and deposition processes.

Secondary Electron Channeling Contrast

• Ion beam can reveal crystal orientations based on how ions interact with materials.
• Provides distinct image contrast not available using SEM techniques.

Challenges and Considerations

• Contamination:
  • Concerns with organic materials and how they interact with vacuum systems.
• Drift Control:
  • Non-conductive materials might drift, affecting imaging precision.
• Material Removal:
  • Different materials (e.g., ceramics, oxides) remove at different rates.

Conclusion

• FIB is a versatile and powerful tool for material manipulation, imaging, and analysis.
• Additional resources available:
  • YouTube videos
  • Introductory courses on FIB applications offered quarterly.