Defect Characterization of Sputter Deposited Au Contacts on N-Type Si1-xGex

Abstract

Sputter deposition of metal Schottky contacts on semiconductors creates damage at and below the surface, often resulting in inferior rectification properties. We have used deep-level transient spectroscopy (DLTS) in an investigation of the electronic properties of defects introduced in n-Si1-x Gex (x=0.0 to 0.25) during RF sputter deposition of 500 nm thick Au Schottky barrier diodes (SBDs). Seven discrete electron defects (ES1–ES7) and a band of defects with a continuous distribution were detected after this processing stage. The defects are compared to those detected in the same material after high and low energy alpha-particle irradiation. It was seen that ES5 detected after sputter deposition is actually two peaks superimposed on each other. Contributions from the E-centre and the divacancy make up this DLTS peak. ES5 has a similar DLTS signature to EA2 introduced during high energy (5.4 MeV) alpha-particle irradiation.