Modeling of aluminum nitride growth by halide vapor transport epitaxy method

A halide vapor transport epitaxy (HVTE) system was designed and built at USAF Research Laboratory to grow high-quality aluminum nitride film at growth rates up to 40 μm/h with the deposition temperature of 1100-1300 °C and the pressure ranging from 3.5-760 Torr (J. Crystal Growth 250 (2003) 1). In order to optimize the growth process, a numerical model, which is capable of describing multi-component fluid flow, gas/surface chemistry, conjugate heat transfer, and species transport, has been developed to help in design and optimization of the HVTE growth system. The partial pressures of aluminum chloride amine adduct, used as the aluminum source, and anhydrous ammonia for the nitrogen, have been measured and used as the inlet boundary conditions in the computational model. By matching predicted and experimental deposition rates, the heterogeneous reaction boundary condition is determined and applied to the substrate. To optimize operating parameters, the comprehensive three-dimensional computational simulations have been performed to study the temperature distribution, species mixing process and AlN deposition rate distribution on the substrate under different geometrical configurations and operating conditions.