The Effects of Ionized Impurities on the Nanoscale Spatial Distribution of the Schottky Barrier

The influence of ionized impurities in the semiconductor upon the local Schottky barrier height of a metal-semiconductor interface is important for contacts in nanoscale devices. A computational model simulates spatially-resolved measurements of the electrostatic potential of various metal-semiconductor interfaces acquired using ballistic electron emission microscopy (BEEM), an STM-based technique. The model assumes a uniform charge density with a set of point charges close to the interface, and generates simulated datasets in the form of Schottky barrier height maps and histograms. The introduction of localized charges causes skewing of the distributions, which are compared to BEEM measurements of Au/Si and Cu/Si Schottky barrier height maps.