Computational fluid dynamics on gaseous and surface chemistry of GaN-MOVPE system for various pressures

Pressure effects on gaseous and surface chemistry of GaN grown by metalorganic vapor phase epitaxy (MOVPE) were studied. In order to obtain a chemical state of molecular species in an MOVPE reactor, computational fluid dynamics simulation was performed for 10 to 300 kPa, in which parasitic reactions among trimethylgallium and ammonia were considered. It was found that adducts of the dimethylgallium-NH₂ family related to Ga-N molecule formation dominated reaction pathways. It was also revealed that a V/III ratio of physisorbed species was increased 2 orders of magnitude and close to a unity with the reactor pressure. These results suggested that MOVPE growth under atmospheric or higher pressures resulted in favourable growth conditions for high quality GaN.