Regulation of oxygen defects in AlGaN-based epilayers grown on high temperature annealed AlN template

The regulation of oxygen (O) point defects in AlGaN-based epilayers grown on high-temperature annealed AlN (HTA-AlN) template by metal–organic chemical vapor deposition (MOCVD) is systematically investigated in this work. The concentration of O impurity in AlN epilayers is restricted to 1 × 1017 cm−3, but decreases by 59 % and 27 % when the AlN layer is replaced by the Al0.5Ga0.5N interlayer (IL) and AlN/Al0.5Ga0.5N superlattice (SL), respectively. By analyzing the growth conditions, the O impurity can be inhibited by raising V/III ratio or decreasing Al component, which increases the formation energy of O point defects according to first-principles calculation. This work provides accurate guidance for regulating O point defects in AlGaN-based materials.