Analysis of the Photochemical Reaction on the Surface for Room Temperature Deposition of SiO2 Thin Films by Photo-CVD using Vacuum Ultraviolet Light

Abstract

We have analyzed the photochemical reaction for the deposition of SiO2 thin films at room temperature in photo-CVD using a vacuum ultraviolet (VUV) excimer lamp with reflection-absorption spectroscopy using a Fourier transform infrared spectrometer (RAS-FTIR). Tetraethoxyorthosilicate (TEOS) was used as a precursor and two types of excimer lamps were used as light sources. The reaction in VUV-CVD is divided into two stages: the reaction in the vapor phase, and the reaction on the surface of the substrate. In this work, we analyzed the latter stage. As a result of analyzing the spectra obtained, it was found that the main reaction for the formation of the SiO2 film was in the latter stage, in which the dissociation of Si–O bonds in Si–O–CH2 in the adsorbed fragments was preceded by the photo-dissociation of C2H5.