Improvement in surface morphology and 2DEG properties of AlGaN/GaN HEMT

Abstract AlGaN/GaN high electron mobility transistor (HEMT) epistructures were grown on SiC substrate using MOVPE. In this paper, the growth of high-quality AlGaN epi-layer in AlGaN/GaN HEMT is reported. The optimization was carried out to improve surface morphology and quality of the AlGaN epi-layer to get high 2DEG (two-dimensional electron gas) properties of the HEMT structure. For this optimization, AlGaN epi-layers were grown with different V/III molar ratio. It was found that both lower and higher V/III molar ratios result in the step flow surface morphology of AlGaN. However, a higher V/III molar ratio results in reduced surface roughness, improved quality of AlGaN, and excellent 2DEG properties of HEMT epi-structure.