CUBIC DOMINANT GAN GROWTH ON (001)GAAS SUBSTRATES BY HYDRIDE VAPOR-PHASE EPITAXY

GaN layers were grown on (001) GaAs substrates by hydride vapor phase epitaxy (HVPE) with buffer layers grown by HVPE under various growth c onditions. The ratio of cubic to hexagonal components in the grown GaN layers was estimated from the ratio of the integrated X-ray diffracti on intensities of the cubic (002) and hexagonal (10 (1) over bar 1) pl anes measured by omega scan. It was found that the cubic/hexagonal rat io greatly depended on the thermal cleaning prior to the buffer layer growth and growth conditions. A thick GaN layer whose cubic component was more than 85% was obtained with thermal cleaning at 600 degrees C for 10 minutes, a similar to 30 nm buffer layer grown at 500 degrees C and a V/III ratio of 300 during growth at 800 degrees C.