Modeling the Growth of Aluminum Gallium Nitride ((Al)GaN) Films Grown on Aluminum Nitride (AlN) Substrates

Report No. ARL-MR-0770
Authors: Dr. Kenneth A. Jones, Dr. Anthony J. Ciani, Dr. Iskander Batyrev, and Dr. Peter W. Chung
Date/Pages: March 2011; 26 pages
Abstract: The goal of this research was to determine if the evolution of dislocations in aluminum gallium nitride (AlGaN) films grown on aluminum nitride (AlN) substrates could be modeled with the goal of determining if there are conditions under which the films are grown so that most of the dislocations created by the mismatch are confined to regions away from the film surface where devices are fabricated. Through crystallographic modeling, we determined that the most probable slip system is the (1122)13<1123> secondary slip system. We also calculated that the energy states associated with the dislocations lie in or near the energy bands, but that the stacking faults create deep donors that can compensate p-type dopants. Modifications to the Parallel Dislocation Simulator (ParaDIS) code used to calculate dislocation creation in face centered cubic (FCC) metals under stress were begun to adapt it for wurtzite hexagonal close packed (HCP) semiconductors such as AlGaN. This includes changing from the 3-Miller indices system used for FCC structures to the 4-Miller indices systems used for HCP structures. The next step is to apply our modified model to the selected slip system.
Distribution: Approved for public release
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Last Update / Reviewed: March 1, 2011