The dopant distribution computed in the modified Chang–Brown model using quasi-steady state approximation

Abstract

In this paper we present computed flow, temperature and concentration fields in the case of Bridgman–Stockbarger semiconductor crystal growth system, using the modified Chang–Brown model. This model is an extension of the initial Chang–Brown model in the framework of the continuum mechanics. The effect of the precrystallization-zone is included by mean of a thin porous layer (of width 10−9 m; size of solid inclusions 10−10 m; porosity 0.9) which reduces the dopant diffusivity from D to Deff=0.917D, increases the heat conductivity from K to Keff=1.1K and does not influence the flow in the zone. In computing, the true unsteady process is replaced with a quasi-steady state process. The obtained results are compared to those obtained using the initial Chang–Brown model. Comparisons prove, that the influence of the precrystallization-zone is relevant.