Structure and Defects in Amorphous Si–O Films

Abstract

Amorphous Si–O films prepared by magnetron sputtering and glow discharge decomposition were investigated by infrared (IR) absorption, electron spin resonance and photoconductivity measurements. Amorphous Si–O films prepared by a glow discharge decomposition of SiH₄+O₂ gas mixture has a high photoconductivity with a wide optical gap, suggesting that hydrogenated amorphous Si–O films are not inferior to hydrogenated amorphous Si–C and Si–N as widegap materials. The compositional dependence of the peak position of the Si–O–Si stretching mode in the IR absorption spectrum for films prepared with various deposition conditions reveals that under a low substrate temperature Si and O atoms tend to be randomly mixed without O–O bonds while under a high substrate temperature they tend to be phaseseparated into Si and SiO₂.