High-Quality GaN Heteroepitaxial Films Grown by Metalorganic Chemical VaporDeposition

摘要

In this paper, we describe the growth and characterization of high-quality GaNheteroepitaxial films grown on basal-plane sapphire substrates using metalorganic chemical vapor deposition. The quality of these films is analyzed by a variety of methods, including high-resolution x-ray diffraction, optical transmission spectroscopy, transmission electron microscopy (TEM), room temperature photoluminescence, and room-temperature Hall measurements. The x-ray diffraction full width at half maximum value of delta theta approx. 37 arc s is the narrowest reported to date for any III-V nitride film on any substrate. The x-ray rocking curves for approx. 0.48 micrometers thick GaN/Al2O3 heteroepitaxial layers exhibit Pendellosung fringes, indicating that even relatively thin films can be of high quality. High-resolution TEM lattice images further attest to the excellent structural quality, showing the films to be completely free of stacking faults. Furthermore, no evidence of columnar growth is observed. jg p2.