Relating Spatially Resolved Maps of the Schottky Barrier Height to Metal/Semiconductor Interface Composition

TL;DR

This study uses nanoscale mapping techniques to relate the local Schottky barrier height variations at metal/semiconductor interfaces to their composition, combining BEEM measurements with spectroscopic analysis.

Contribution

It introduces a method to correlate nanoscale SBH maps with interface composition using spectral fitting and spectroscopic validation.

Findings

SBH distributions show multiple maxima indicating mixed metal species.

Spectral fitting estimates interface composition with good agreement to RBS and XPS.

Nanoscale SBH mapping reveals local compositional variations at the interface.

Abstract

The Schottky barrier height (SBH) is mapped with nanoscale resolution at pure Au/Si(001) and mixed Au/Ag/Si(001) interfaces utilizing ballistic electron emission microscopy (BEEM) by acquiring and fitting spectra every 11.7 nm over a 1 micron by 1 micron area. The energetic distribution of the SBH for the mixed interfaces contain several local maximums indicative of a mixture of metal species at the interface. To estimate the composition at the interface, the distributions are fit to multiple Gaussians that account for the species, "pinch-off" effects, and defects. This electrostatic composition is compared to Rutherford backscattering spectrometry (RBS) and x-ray photo-emission spectroscopy (XPS) measurements to relate it to the physical composition at the interface.