The Effect of Gan Single Crystal Substrate Characteristics On Homo-Epitaxial Gan Films

Abstract

Gallium nitride (GaN) has attracted much attention as an important wide bandgap semiconductor. In this paper, GaN films are grown directly on GaN substrates with completely different characteristics, and it is found that the quality, surface roughness, stress and other characteristics of GaN films are directly related to GaN substrates. The smaller the warpage and roughness of wafer, the smaller the warpage and surface roughness of GaN film obtained by homo-epitaxy. Various methods such as alkali etching and multiphoton photoluminescence (MPPL) have revealed that GaN screw dislocations (TSD) extend into the GaN epitaxial layer, and that edge dislocations (TED) and mixed dislocations (TMD) appear as hexagonal holes in the GaN epitaxial layer. It was also found that there is a relationship between the strain of the GaN epitaxial layer and the strain of the substrate. Finally, the basic performance of the GaN based HEMT device was demonstrated. This study can provide reference for growing higher quality and less defective GaN films, which will be beneficial for further applications of more stable and high performance GaN-based devices.

Keywords: GaN, homo-epitaxial, surface morphology, dislocation, strain