Effect of Pressure on Plasma‐Assisted Chemical Vapor. Deposition of Silicon Oxide(s)

In most chemical vapor deposition processes, the film growth rate increases with the concentrations of the reactant gases. However, in the plasma‐assisted chemical vapor deposition of silicon oxide films, the deposition rate decreases when the concentrations of silane and nitrous oxide are increased by enhancing the reactor pressure from 0.5 to 2 torr (66 to 270 Pa). The deposition rate and the plasma properties have been examined for various reactor pressures to seek an improved understanding of the deposition process. Photo emissions from the plasma were monitored to determine the species present in the plasma and to calculate electron energy and density. With the increase in pressure, both the electron temperature and density decreased, and, consequently, the concentration of active species decreased. Although the concentrations of both silane and nitrous oxide increased with total pressure, the deposition rate decreased. The results emphasize the crucial importance of electron energy and density to generate sufficient concentration of active species responsible for film growth.