Chemical and electronic structure of the SiO2/Si interface

Abstract

The motivation for understanding the physics and chemistry of the SiO₂/Si interface lies in the pivotal role it plays in current metal-oxide-semiconductor (MOS) technology. In this paper, we are concerned with the chemical structure of this interface and its relationship to both MOS device processing chemistry and, ultimately, the resultant electrical device properties. Emphasis is placed on the use of X-ray photoemission to probe the structure of the SiO₂ near the SiO₂/Si interface as well as the composition of the SiO₂/Si chemical transition boundary itself. Complementary data from a wide range of other techniques such as ²⁹Si NMR, ellipsometry, SEXAFS, and a variety of electrical probes are also considered. The topics discussed include the presence of a structurally-distinct region of SiO₂ near the interface and its effect on the SiO₂ band gap, the distribution and crystallographic dependence of suboxide states at the monolayer SiO₂/Si transition boundary, the effect of electron irradiation on the SiO₂ network structure, the influence of hydrogen on the SiO₂ valence band discontinuity between SiO₂ and Si, and the influence of processing chemistry on the chemical and electronic structure of the interface.