C3H8-SiCl4-H2시스템에서 FactSage를 이용한 압력-조성-온도 3차원 상평형도의 응용

Abstract

In order to deposit a homogeneous and uniform β-SiC films by chemical vapor deposition, we constructed the phase-diagram of β-SiC over graphite and silicon via computational thermodynamic calculation considering pressure(P), temperature(T) and gas composition(C) as variables in C 3 H 8 -SiCl 4 -H 2 system. During the calculation, the ratio of Cl/Si and C/Si is maintained to be 4 and 1, respectively, and H/Si ratio is varied from 2.67 to 15,000. The P-T-C diagram showed very steep phase boundary between SiC+C and SiC region perpendicular to H/Si axis and also showed SiC+Si region with very large H/Si value of ~6700. The diagram can be applied not only to the prediction of the deposited phase composition but to compositional variation due to the temperature distribution in the reactor. The P-T-C diagram could provide the better understanding of chemical vapor deposition of silicon carbide.