Fourier transform infrared spectroscopy of corona-processed silicon dioxide films

Abstract

The application of corona discharge during the thermal oxidation of Si substrates has been shown to dramatically enhance the growth rate at low temperatures. Fourier transform infrared spectroscopy (FTIR) of the films shows that these films have properties close to those of untreated oxides. No-hydrogen related impurities are introduced into these films by the corona processing. However, subtle changes in the shape and intensity of the main Si–O–Si asymmetric (AS) stretch vibration at 1070 cm−1 indicate that the films have a different structure than that of standard thermal SiO2 films. The changes in frequency and full width half maximum (FWHM) of the AS peak are described as a function of corona-treatment parameters. The peak frequency and FWHM of positive-corona-treated films shift in a direction consistent with relaxation of thermal SiO2 films. However, for negative-corona-treated films the shifts are in the opposite (unexpected) direction. Coupled FTIR and etch-back measurements indicate that both positive- and negative-coronaprocessed films are homogeneous.