FOURIER-TRANSFORM INFRARED-SPECTROSCOPY OF CORONA-PROCESSED SILICON DIOXIDE FILMS

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 th e films shows that these films have properties close to those of untre ated oxides. No-hydrogen related impurities are introduced into these films by the corona processing. However, subtle changes in the shape a nd intensity of the main Si-O-Si asymmetric (AS) stretch vibration at 1070 cm(-1) indicate that the films have a different structure than th at of standard thermal SiO2 films. The changes in frequency and full w idth 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 o f thermal SiO2 films. However, for negative-corona-treated films the s hifts are in the opposite (unexpected) direction. Coupled FTIR and etc h-back measurements indicate that both positive-and negative-corona-pr ocessed films are homogeneous. (C) 1998 American Vacuum Society. [S073 4-211X(98)06702-X].