Direct measurement of donor-like interface state density and energy distribution at insulator/AlGaN interface in metal/Al_2O_3/AlGaN/GaN by photocapacitance method

摘要

We determined the energy distribution of donor-like interface state density D_(itD)(E) at the Al_2O_3/ AlGaN interface in a metal/Al_2O_3/AlGaN/GaN heterostructure (MISH) capacitor. In this order, we developed a point-by-point graphical method based on the measurement and simulations of the MISH photocapacitance versus ultraviolet light intensity. We found a tail-like shaped D_(itD)(E) strongly decreasing from the value of 5 × 10~(13) to 4 × 10~(12) eV~(-1) cm~(-2) in the energv range between 0.12 eV and 0.45 eV from the AlGaN valence band edge.