Evidence of space charge limited flow in the gate current of AlGaN/GaN high electron mobility transistors

Abstract

Room temperature gate leakage current measurements as a function of gate bias voltage are reported for different AlGaN/GaN high electron mobility transistors and interpreted in terms of space charge limited flow in the presence of shallow traps through very small area conductive leakage paths already present or formed under electrical stress in the gate stack device area. Transport parameters for electrons following these paths are extracted, and the observation of gate electron velocity saturation in stressed devices indicates that newly created leakage paths form predominantly in high electric field gate edge regions. © 2012 American Institute of Physics.