Simulation and experimental investigation of recessed-gate AlGaN/GaN HEMT

The effect of recessed-gate depth on device characteristics was analyzed. The device characteristics with different recessed-gate depth were simulated by using SILVACO and the variation of saturation current, maximum conductance and threshold with different recessed-gate depth were obtained. With increasing recessed-gate depth, the saturation current reduces and maximum conductance increases and the threshold shifts to positive direction of X-axis. High electron mobility transistors of AlGaN/GaN heterostructure grown on sapphire substrates with different recessed-gate depth were fabricated. The simulation of different recessed-gate depth device characteristics were validated by comparing experiments with the simulation results. The discrepancies between simulation and experiment were analyzed in the aspects of etching damage and interface states.