The influence mechanism of Al2O3 layer and etching depth on 2DEG sheet density in gate-recessed Al2O3/AlGaN/GaN MOS-HEMTs

Capacitance-voltage (C-V) characteristics have been measured in this paper to calculate the depth profiles of GaN carrier concentration in four different structure GaN-based HEMTs, revealing the consequences of Al₂O₃ oxide layer and etching depth on two-dimensional electron gas (2DEG) sheet density. Combining the energy band diagrams with the theoretical calculation formula of 2DEG, we analyzed corresponding influence mechanism systematically.