2 in. Free-standing GaN grown by HVPE with sputtered AlN buffer on GaAs substrate

Abstract

A magnetron sputtered AlN buffer layer is applied for preparing 2 in. free-standing (FS) GaN on the GaAs substrate by hydride vapor phase epitaxy (HVPE). The AlN buffer layer with excellent compactness can prevent As atoms from diffusing to the GaN growth surface. Thus it serves as an effective protective layer for GaAs substrate and also a seed layer for the deposition of GaN in the early stage of the high-temperature GaN growth. Benefiting from the decomposition property of GaAs at temperature higher than 900 °C, thick GaN film self-separated completely from GaAs substrate during growth. By this way, a 2 in. FS-GaN layer with the thickness of 1.3 mm is finally obtained after the long growth time about 20 h.