HETEROEPITAXIAL GROWTH OF GAN ON GAAS BY ECR PLASMA-ASSISTED MBE

Heteroepitaxial GaN was grown on (100) GaAs by plasma assisted molecular beam epitaxy. The effect bf GaAs surface treatment and low temperature grown buffer layers are investigated. Optimized growth conditions are obtained using X-ray rocking curve and Raman Spectroscopy. High resolution cross-sectional TEM photographs show the GaN films are defective near the interface and have columnar domains. Only the (0002) peaks of wurtzite GaN are observed in X-ray Diffraction patterns and the FWHM of(0002) GaN peak is about 720 seconds. We investigate the effect of heat treatment of GaN films at trmperatures between 600 degrees C to 1000 degrees C for 30 minutes. It is observed that the crystalline quality of the GaN films is relatively little changed by post-growth heat treatment.