Accurate Method to Measure SiGe/Si/SiGe Interfacial Widths via Atom Probe Tomography

Accurate Method to Measure SiGe/Si/SiGe Interfacial Widths via Atom Probe Tomography

Scientific Achievement
(a) APT reconstruction and (b) STEM image of 8nm Si well in SiGe/Si/SiGe heterostructure. (c) HAADF-STEM atomic column intensities vs. APT Ge concentrations for bottom (SiGe/Si) and top (Si/SiGe) interfaces. Sigmoidal fits for acquired data show excellent correlation between APT and STEM. (hi-res image)

A step-by-step method was developed to accurately measure Si/SiGe interfacial widths via atom probe tomography (APT) with 1Å precision after application of a new APT data processing method.

Significance and Impact

There is a significant need for advanced characterization techniques that can accurately quantify Si/SiGe interfacial composition and sharpness as devices become more advanced.

Research Details

- SiGe/Si/SiGe heterostructures fabricated by HRL
- Interfacial widths measured by APT and STEM
- Comparison of APT and STEM data showed discrepancies in interfacial widths for reconstructed APT data
- A post-reconstruction data process mitigates errors by correcting artificial density differences in the APT data 
 
O. Dyck, D.N. Leonard, L.F. Edge, C.A. Jackson, E.J. Pritchett, P.W. Deelman, and J.D. Poplawsky, Adv. Mater. Interfaces, accepted for publication and available as “early view” paper (2017).  DOI: 10.1002/admi.201700622

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