SiO2/Si interfacial structure on vicinal Si(100) studied with second-harmonic generation

Abstract

Surface second-harmonic generation (SHG) has been used to reveal the symmetry characteristics of buried interfaces on oxidized vicinal Si(100). For native oxides, onefold and threefold symmetries are prominent, arising from the presence of steps and ordered Si-O bonds in the vicinity of the steps, respectively. For thermal oxides grown at 900 °C, twofold symmetry is most prominent, consistent with the presence of highly oriented microcrystallites at the buried interface. SHG measurements of postoxidation annealing of oxides grown in steam are consistent with the amount of stress reduction occurring as a result of annealing being too small to be observed by SHG, and with hydrogen leaving the buried interface below 600 °C.