Transport effects in the sublimation growth of aluminum nitride

In this paper, a detailed two-dimensional model accommodating the thermal convection and Stefan flow is formulated for AlN sublimation growth. Some assumptions are applied in the model and inspected by the experimental data. A detailed numerical investigation is carried out for the transport effect on the sublimation growth. Theoretical predictions agree with the experimental data at pressure above 100Torr and current operating temperature (seed temperature) ranging from 1700 to 1900 degreesC. The activation energy of the growth rate is 681KJ/mol close to the sublimation heat of aluminum nitride. Nevertheless, at low pressure less than 100Torr, a combination of surface crystallization model is necessary to describe the process kinetics correctly. Meanwhile, a detailed heat transfer model for furnace temperature gradient is required for more accurate prediction of growth rate. (C) 2000 Elsevier Science B.V. All rights reserved.