Au and Al interface reactions with SiO2

Abstract

The chemical bonding, extent, and evolution of metal-oxide semiconductor interface regions have been probed with soft-x-ray photoemission spectroscopy following room-temperature, in situ metallization. We identify strong atomic rearrangement and charge transfer at metal-SiO2 interfaces. The quantitatively different processes found for Au and Al suggest new structural models. For Al-SiO2, Al first clusters about each surface O and then grows Al2O3 by reducing SiOx (X < 2) and leaving excess Si at the interface. In contrast, Au forms islands on SiO2 with evidence of Au–Si bonding, causing an SiOx layer beneath the contact.