Electronic Structure of Thin Gold Film Deposited on Silicon Substrate Studied by Auger Electron and X-ray Photoelectron Spectroscopies

Abstract

Auger Electron Spectroscopy (AES) measurements of very thin ( \\lesssim150 Å) gold (Au) films deposited on clean surfaces of silicon (Si) substrates are made in order to study Si/Au interface. The AES spectra taken from the surfaces of these Au films are composed of both Si and Au spectra suggesting that the interfaces are diffuse instead of sharp. The Si spectra show splitting and are different from those of pure Si. Since the same splitting can be observed in the specimen obtained by quenching from Si–Au eutectic liquid, X-ray Photoelectron Spectroscopy (XPS) is applied to the same kind of quenched specimen to investigate the origin of the splitting, through the changes in the XPS spectrum of Au d-band compared with that of pure Au. Itis proposed that Si in the diffuse interface region is metallic with 4 valence electrons (3s and 3p) to interact with 6s and 5d-electrons of Au.