Nanoscale Schottky barrier visualization utilizing computational modeling and ballistic electron emission microscopy

Abstract

The electrostatic barrier at a metal semiconductor interface is visualized using nanoscale spatial and meV energetic resolution. A combination of Schottky barrier mapping with ballistic electron emission microscopy and computational modeling enables extraction of the barrier heights, the hot electron scattering, and the presence of localized charges at the interface from the histograms of the spectra thresholds. Several metal semiconductor interfaces are investigated including W/Si(001) using two different deposition techniques, Cr/Si(001), and mixed Au-Ag/Si(001). The findings demonstrate the ability to detect the effects of partial silicide formation in the W and Cr samples and the presence of two barrier heights in intermixed Au/Ag films upon the electrostatic barrier of a buried interface with nanoscale resolution. This has potential to transform the fundamental understanding of the relationship between electrostatic uniformity and interface structure for technologically important metal semiconductor interfaces.