Extraction of net acceptor type trap density in semi-insulating GaN layers grown on Si substrate by DC I-V measurement

A simple quantitative method is proposed to estimate net acceptor-type trap density (N-T-N-D, where N-T denotes a gross acceptor-type trap density, and N-D denotes a donor density) in semi-insulating GaN layers, widely used as the electron channel layer in AlGaN/GaN heterojunction field-effect-transistors. The DC current-voltage characteristics of a semi-insulating GaN layer on a Si wafer have a threshold voltage (V-TH). Band diagram simulation reveals that N-T-N-D determines V-TH,V- and hence, the N-T-N-D in semi-insulating GaN films can be experimentally estimated by measuring V-TH.