A Study on the Behavior of SiO2 Film Precursors with Trench Deposition Method for SiH4/O2 Low Pressure Chemical Vapor Deposition

Silicon dioxide thin films have been deposited from silane and oxygen at 540 K and 3.5 Torr in a cold-wall reactor. The trench deposition method is applied to clarify the behavior of film precursors for the SiO2 deposition. It has been found that surface reactions scarcely contribute to the deposition in the present conditions, and that the overall sticking probability of the film precursor changes significantly with the substrate temperature. This phenomenon is shown to be satisfactorily explained by the model that the precursors formed by gaseous reactions consist of several kind of radicals with different sticking probabilities. It is also shown that the decrease in the deposition rate for O2-excess region corresponds to the radical concentration in the gasphase.