Quantitative analysis of Si/SiGeC superlattices using atom probe tomography

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Silicon-Germanium (SiGe) alloys are critical for advanced electronic devices.
• Understanding dopant and impurity localization at the nanoscale is vital for electronic properties.
• SiGeC superlattices present unique challenges for precise material characterization.

Purpose of the Study:

• To quantify carbon and germanium concentrations in as-grown Si/SiGeC superlattices.
• To investigate the influence of analysis conditions and annealing temperature on quantification.
• To understand the spatial distribution and clustering of carbon in annealed SiGeC.

Main Methods:

• Atom Probe Tomography (APT) was employed for high-resolution elemental analysis.
• Systematic variation of APT analysis parameters to optimize data acquisition.
• Analysis of samples subjected to different annealing temperatures to study carbon behavior.

Main Results:

• Quantitative analysis of carbon and germanium is achievable with optimized APT conditions, specifically using an intermediate electric field.
• Carbon ion evaporation exhibits significant spatial and temporal correlations during APT.
• Annealed SiGeC samples show inhomogeneous carbon distribution, forming small clusters.

Conclusions:

• Atom Probe Tomography is a powerful technique for nanoscale chemical analysis of SiGeC materials.
• Optimized analysis conditions are crucial for accurate quantification of elements like carbon and germanium.
• The observed carbon clustering in annealed samples provides insights into material processing and properties.