ELASTIC STRAIN RELAXATION IN GAN-ALN-GAN SEMICONDUCTOR-INSULATOR-SEMICONDUCTOR STRUCTURES

We calculated the elastic strain relaxation in wurtzite GaN-AIN-GaN semiconductor-insulator-semiconductor (SIS) structures. Elastic strain tenser components, elastic energy, the density of the misfit dislocations, and the other parameters of the system were obtained as functions of the AIN layer thickness. Theoretical values of the elastic strain relaxation are in satisfactory agreement with experimental data extracted from the capacitance-voltage (C-V) characteristics of GaN-AIN-GaN SIS structures. Our results confirm that the gradual relaxation process starts from 30 Angstrom AIN film thickness. The uniform contributions to the elastic strain tenser components decrease by approximately an order of magnitude when the film thickness increases from 30 to 100 Angstrom. Commensurate with this decrease is an increase in a nonuniform contribution of the misfit dislocations. The dislocation interactions lead to redistribution of dislocations within the 30-60 Angstrom range of AIN film thicknesses. (C) 1995 American Institute of Physics.