Model development of GaN MOVPE growth chemistry for reactor design

Abstract

The metalorganic vapor phase epitaxy of GaN is complicated by the extensive and pervasive complex gas phase chemistry within the growth system. This gas phase chemistry leads to the high sensitivity of the material properties on the detailed fluid dynamics within the system. Computational fluid dynamics (CFD) based reactor modeling combined with gas phase kinetics studies was used to determine the transport and reaction behavior within a high performance vertical MOVPE reactor. The complexity of the growth chemistry model was increased in a step-wise fashion. At each step, the concentration profiles were determined using available recent kinetic data. The high gas flow rate typically employed in GaN MOVPE results in a very thin high-temperature flow sheet above the growth front, leading to an extremely high thermal gradient. Within this thin high-temperature flow sheet, a stratified chemical structure is formed as a result of the unique thermal fluid environment. This stratified structure is closely related to the transport and reaction behavior within GaN MOVPE processes and forms part of the engineering guidelines for GaN MOVPE reactor design.