Defect distribution in a-plane GaN on Al_2O_3

摘要

The authors studied the structural and point defect distributions of hydride vapor phase epitaxial GaN film grown in the [11-20] a direction on (1-102) r-plane sapphire with metal-organic vapor phase deposited a-GaN template using transmission electron microscopy, secondary ion mass spectrometry, and positron annihilation spectroscopy. Grown-in extended and point defects show constant behavior as a function of thickness, contrary to the strong nonuniform defect distribution observed in GaN grown along the [0001] direction. The observed differences are explained by orientation-dependent and kinetics related defect incorporation.