Analysis of sublimation growth of bulk SiC crystals in tantalum container
Sublimation growth of SiC bulk crystals in tantalum container is studied both experimentally and theoretically. The model of heterogeneous processes occurred on the side wall of the tantalum container proposed recently in Ramm et al. (Mat. Sci. Eng. B 61–62 (1999) 107) is extended to take into account the process of carbon gettering by the container side wall. We formulate a quasi-steady approach for modeling of the bulk crystal growth. Using this concept we predict evolution of the crystal shape and study processes which govern SiC bulk crystal growth. We apply anisotropic thermal elastic analysis to predict stress distribution in the growing crystal. For the first time a model of dislocation formation is applied for SiC bulk growth to compute dislocation density field in highly stressed areas of the growing crystal.
Fig. 1. Scheme of the growth system: (1) graphite foam, (2) tantalum container, (3) SiC powder charge. The upper inset shows the part of the container near the seed. One-dimensional temperature distribution over the seed surface at the initial stage of the growth is shown in the lower inset.
Source: Journal of Crystal Growth