Thermodynamical and kinetic study of the GaN growth by HVPE under nitrogen

The growth of GaN by HVPE was analysed by means of a thermodynamical and ki netic study. The thermodynamical constants of the reactions involved in the GaN growth and the partition functions of the molecules used in the kineti c study were calculated. The kinetic coefficients and the activation energi es of the reactions were tabulated. Good agreement was obtained between the model and the experimental results. The influence of the reactor geometry and of the parasitic nucleation on the glass walls of the reactor was demon strated. After analysing the physical phenomena which might take place in t he vapour phase, we concluded that the vapour phase was not homogeneous. Th e reaction of formation of GaCl3 from HCl and GaCl appears to be incomplete at the GaCl inlet, and almost complete over the substrate. Both effects ex plain the difficulty of growing GaN layers without extraneous deposit. (C) 2001 Elsevier Science B.V. All rights reserved.