Full simulation of silicon chemical vapor deposition process

Abstract

Abstract. Chemical vapor deposition (CVD) process composes a complex system, where chemical reaction and heat and mass transfer interact with each other. And these macro-scale phenomena are deeply related to micro-scale mechanics. Hence multi-scale analysis is required to understand these complicated phenomena and to develop full-scale simulator of the CVD reactor. In this paper, we present the macro-scale simulation by the DSMC method. In those reactors, sometime the important species such as the reactive intermediates have extremely low density ratio. This causes the large statistical fluctuation in the DSMC method, where the number of particles and the calculation time are limited. We propose a new numerical method for this kind of problem and the whole process of silicon CVD is simulated by the new method. We simulate the following CVD process: the gas mixture of silane and hydrogen forms a free expansion jet through a nozzle orifice at the top of the reactor and interact with the heated substrate that is set vertical to flow, where silane decomposes into silylene and silane and silylene deposit onto the surface. It is confirmed that the new method is very effective and make it possible to analyze the CVD process more precisely.

Assessment of conservative weighting scheme in simulating chemical vapour deposition with trace species

“…Thus, a particle representing a trace species would be given a lower weight than particles representing more abundant species. The scheme can also be extended to treat the chemical reaction for the steric factor in gas-phase and the reactive probability of the surface reaction, which we call extended conservative weighting scheme (ECWS) [21].…”