Computational Design of Silicon Suboxides: Chemical and Mechanical Forces on the Atomic Scale

Abstract

Silicon suboxides play an important role in different industrial applications, particularly in the form of the Si-SiO 2 interface, which is one of the key elements in present day microelectronics and potentially in future nano-electronics as well. This paper focuses on the chemical and mechanical effects related to the existence of different oxidation states of Si atoms in SiO x systems with various Si:O composition and topology, such as O atoms in Si, the Si-SiO 2 interface, and O vacancies in SiO 2 . We compare the stress-strain relation in SiO 2 interfaces with (100), (111) and (110) surfaces, the relative stability of oxygen vacancies at different locations in Si-SiO 2 layers and defects in Si and SiO 2 crystals related to O migration. Our study is based on ab initio computations of molecular and periodic systems with both localized and plane wave basis sets.

On the c-Si|a-SiO2 Interface in Hyperthermal Si Oxidation at Room Temperature

“…Interfacial Stresses during Oxidation. The interfacial stress, which can be thought as a combination of chemical and mechanical (physical) stresses, 65 plays an important role in the reliability of gate oxides with its ultrathin interface. 63 The chemical stress at the interface is associated with Si atoms that have an intermediate oxidation state between 0 (in Si) and 4+ (in SiO 2 ).…”

“…Mechanical stress causes the deformation of bonds and bond angles at the interface. Korkin et al 65 suggested that the chemical and the mechanical stress make comparable contributions to the total Si|SiO 2 interface stress.…”