Particle generation and film formation in an atmospheric-pressure chemical vapour deposition process using tetraethylorthosilicate

Abstract

Effects of an oxygen flow rate on film formation and nanometre-sized particle generation in the gas phase were examined simultaneously in an atmospheric-pressure chemical vapour deposition reactor using tetraethylorthosilicate (TEOS). The critical temperature for particle generation decreased rapidly to 340‡C from 740‡C with increasing oxygen flow rate, but it decreased slightly to 600‡C from 700‡C for film formation. There were no conditions where film was deposited without particle generation in a TEOS/O2 system. The nanometre-sized particles generated in the systems were amorphous and non-spherical, and their size distributions were polydisperse. The Fourier transform infrared (FT-IR) and thermal desorption (TDS) spectra of the particles were not affected by oxygen flow rate, and showed that the particles contained a small amount of an ethoxy group and a relatively large amount of a hydroxyl group. It was found from comparisons between FT-IR and TDS spectra of particles and films that the SiO2 films were formed by Β-elimination reactions, where C2H4 and H2O are released from the ethoxy group.