Key Laboratory of Microelectronic Devices&Integrated Technology,Institute of Microelectronics,Chinese Academy of Sciences,Beijing 100029,China;
Institute of Microelectronics,University of Chinese Academy of Sciences,Beijing 100049,China;
ultrathin-barrier AlGaN/GaN heterostructure; low thermal budget; Au-free ohmic contact; micro-patterned ohmic recess; MIS-HEMTs; transfer length;