Failure mechanisms of silicon-based atom-probe tips

Area of Science:

• Materials Science
• Surface Science
• Analytical Chemistry

Background:

• Atom-probe (AP) analysis is a powerful technique for materials characterization.
• Tip rupture during AP analysis of silicon-based samples is a common and significant problem.
• Focused Ion Beam (FIB) milling is widely used for preparing samples for AP analysis.

Purpose of the Study:

• To investigate the stability and failure mechanisms of silicon tips prepared via FIB milling for AP analysis.
• To identify the root causes of tip failure during sample preparation and analysis.
• To propose strategies for avoiding tip failure and improving AP analysis success rates.

Main Methods:

• Focused Ion Beam (FIB) milling for silicon tip preparation.
• In-situ observation and analysis of tip failure mechanisms.
• Correlation of failure modes with sample preparation and analysis conditions.

Main Results:

• Four primary failure mechanisms were identified: apex deformation, oxide layer detachment, cap layer delamination, and in-situ voltage-induced failure.
• Evidence linking specific preparation steps and analysis parameters to each failure mode was gathered.
• Understanding these mechanisms is crucial for optimizing silicon tip stability.

Conclusions:

• Tip failure in AP analysis of silicon is multi-factorial, involving material properties, preparation techniques, and analysis parameters.
• Addressing apex deformation, oxide/cap layer adhesion, and voltage management can mitigate failure.
• Implementing preventative measures will enhance the reliability and success of AP analysis for silicon-based materials.