Atomic Layer Epitaxy of GaN in a Multi-Wafer Rotating Disc Reactor

GaN and other III-V nitrides can be used for fabricating visible/UV optoelectronic devices. Sequential exposure of reactants using a commercial microwave Plasma Enhanced Atomic Layer Epitaxy reactor is proposed to grow high quality GaN films. The technique allows two dimensional layer-by-layer growth which reduces nitrogen vacancies commonly observed in the GaN films. PE-ALE also allows deposition at reduced growth temperatures, which can reduce the loss of nitrogen from the solid phase during growth. A movable mechanical barrier is used to divide the chamber into multiple zones. Each zone can supply source gas, purging hydrogen or excited nitrogen. The substrate, which continuously rotates beneath the barrier, is alternately exposed to the individual gases. Each revolution will result in one monolayer of GaN deposition. Since the growth rate of one monolayer per cycle is insensitive to growth parameters, uniform films over a large area can be obtained.