A 2-DIMENSIONAL DIFFUSION-MODEL FOR LIQUID-PHASE ELECTROEPITAXIAL GROWTH OF GAAS

This paper presents two-dimensional computer simulations of liquid pha se electroepitaxial (LPEE) growth of GaAs based on a rational mathemat ical model. This model includes heat transfer, diffusive mass transpor t, electromigration, and Peltier and Joule effects. The governing equa tions are solved numerically using a finite volume method. Simulations are presented for three different growth cell configurations to inves tigate: (i) temperature and concentration distribution in the growth c ell, (ii) the effect of applied electric current density and substrate thickness, and (iii) the contribution of electromigration and Peltier cooling to the overall growth rate. The results show that the magnitu de of the relative temperature at the growing interface is controlled mainly by Peltier cooling for thin substrates (< 0.2 cm) and small ele ctric current densities (< 20 A/cm(2)). Joule heating becomes signific ant only for thick substrates and high electric current densities. For all configurations investigated, electromigration is found to be the dominant growth mechanism. In critical regions of the growth cell, rel atively small changes in the configuration are found to have a signifi cant impact on the process and on the degree of non-uniformity of the grown crystal.