[摘要]：In this work, we include the polarization effect within the AlGaN barrier into calculation of the near-surface electrical field E-S underneath the Schottky contact metal which determines the field-dependent characteristics of reverse gate leakage current of AlGaN/GaN high electron mobility transistors. High-frequency capacitance-voltage measurement combined with electrostatic analysis is used to estimate E-S as a function of reverse bias voltage. The resultant log(I/E-S) versus root E-S curves over a temperature range from 293 to 453 K agree well with the predicted model of Frenkel-Poole (FP) emission of electrons up to the conductive states of threading dislocations. Around zero bias, the reverse polarization-field-induced FP emission current is balanced by a forward defect-assisted tunneling current, both of which follow the same temperature dependent characteristics. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3499364]
