Comprehensive study on chemical structures of compositional transition layer at SiO₂/Si(100) interface

The angle-resolved Si 2p photoelectron spectra arising from the transition layers formed on both sides of the SiO₂/Si(100) interface covered with more than one SiO₂ monolayer, which is device grade, were measured with the probing depth of nearly 2 nm. The novel analytical procedure of these spectra is developed by considering that one SiO₂ monolayer, two compositional transition layers (CTLs), and one Si monolayer on Si substrate surface are continuously connected with each other. It was found for the interface formed in dry O₂ at 900 °C that two CTLs constitute the first and second CTLs. The first CTL formed at the interface consists mainly of Si1+, Si2+, and Si0 and the second CTL formed on the first CTL consists mainly of Si3+ and Si4+. Influences of oxidation temperature, annealing in forming gas on the chemical structures of transition layers formed on both sides of the interface are also discussed.