Formation of the porous structure of silicon dioxide thin layers during silane oxidation

摘要

Modeling of silicon dioxide deposition is carried out at the level of elementary chemical gas-phase stages for low pressure and plasma enhanced CVD processes. It is shown on the basis of modeling results compared with the previously reported experimental data that the formation of porous structure of silicon dioxide films deposited by means of silane oxidation is governed by gas-phase intermediates and products (especially water) formed during oxidation. Modeling results allowed us to explain the role of different additives (e.g. ammonia, propylene) that were observed to affect the porous structure of films: ammonia causes a decrease in total film porosity, while propylene allows one to obtain the films with high porosity and uniform pore size. Thus the chemical nature of the effect of gas-phase elementary stages of the process on the characteristics of the resulting solid silicon dioxide film is revealed.