High Temperature Ramping Rate for GaAs (111)A Substrate Covered with a Thin GaN Buffer Layer for Thick GaN Growth at 1000°C

Abstract

The effects of temperature ramping rate on GaAs (111)A substrate covered with a thin GaN buffer layer grown at 550°C are investigated in order to determine the ideal parameters for protecting the substrate from thermal decomposition during the growth of a thick GaN layer at 1000°C by metalorganic hydrogen chloride vapor-phase epitaxy (MOHVPE). Crystallization and agglomeration of the GaN buffer layer during heating is found to increase markedly as the temperature ramping rate is decreased, and thus high ramping rates are found to be applicable to the high temperature growth of GaN on GaAs substrate. When a temperature ramping rate of 20.9°C/min is used, a thick GaN layer exhibiting no voids or cracks is obtained due to the protection of the GaAs substrate.