Thermodynamic Study, Composition, and Microstructure of Low‐Pressure Chemical Vapor Deposited Silicon Dioxide Films Grown from TEOS / N 2 O Mixtures

Abstract

A calculational thermodynamic investigation of the chemical vapor deposition of , films from mixtures has been performed based on the minimization of the Gibbs energy of the Si‐O‐C‐H‐N system. The results illustrate the influence of temperature, pressure, and initial gas composition on the formation of stable phases. films have been grown in a conventional horizontal low‐pressure chemical vapor deposition reactor at 983 and 1093 K and pressure 0.3 Torr. X‐ray photoelectron spectroscopy measurements have shown that the deposited films contained carbon impurities with concentration decreasing with the increase of the flow ratio, in qualitative agreement with the thermodynamic calculations. X‐ray photoelectron spectroscopy and Rutherford backscattering spectroscopy measurements have shown that the O/Si ratio in the films was less than 2 and that it was approaching this value for high flows. Atomic force microscopy measurements have shown that the films exhibited a granular morphology with grain size increasing with the deposition temperature and the flow ratio. The analysis of Fourier transform infrared spectra taken on the films has shown that the absorption near 1080 cm −1 was due to the presence of more than one oscillator, the positioning of which was related to variations in the O/Si ratio, the interatomic distances, and the bond angles in the films.