Abstract
Silicon oxide (SiO2) layers were fabricated at a low temperature of 400 °C by the oxidation of single-crystal Si substrates and hydrogenated amorphous Si (a-Si:H) films using stable plasma excited at atmospheric pressure with a 150 MHz very high frequency (VHF) power. The utilization of Ar/O2 plasma led to an oxidation rate higher than that using He/O2 plasma while maintaining both SiO2/Si interface and SiO2 bulk qualities. The oxidation of a-Si:H was also effective in increasing the oxidation rate than the oxidation of single-crystal Si. Although the a-Si:H film contained a large amount of H atoms bound to Si atoms, the atmospheric-pressure VHF plasma significantly induced the hydrogen evolution from the film and the transformation of the film into a SiO2 layer. As a result, this study showed that the utilization of atmospheric-pressure VHF plasma was beneficial to the realization of a highly efficient formation process of stoichiometric and pure SiO2 layers at low temperatures.