ABSTRACT
Abstract. High A1 composition AlGaN/GaN hetero-structure was grown on GaN layer on the 2-inch sapphire substrate (GaN template) by MBE. We investigated the crystalline and electrical properties while changing growth temperature from 680°C to 870°C. The A1 composition of AlGaN was found to be 0.4-0.6 from XRD measurement. We obtained the high sheet carrier density of over 1.5x l013cm'2 in all the growth temperature region, due to high A1 composition of AlGaN barrier layer. When growth temperature was 830°C, the A1 composition of the AlGaN layer was 50% and the sheet resistance was the minimum, 2 5 5 0 /□ , where the sheet carrier density and the mobility was 2.34xl013cm-2 and lOSOcmV'V1, respectively. We certified 2-DEG characteristics by Hall measurement in the temperature range from 20K to 300K.
