Physical Insights Into the Impact of Surface Traps on Breakdown Characteristics of AlGaN/GaN HEMTs—Part I

Impact of surface traps on the breakdown characteristics of AlGaN/GaN HEMT devices is revealed using detailed TCAD computations and supporting experiments. Detailed mechanism explaining the role of surface traps in modulating channel electric field under various surface trap, device design, gate-stack, and applied voltage conditions is discussed. Experimental analysis with different surface conditions shows the measured electric field profile, using electro-luminescence experiments, to be in complete agreement with the computational findings. Device design guidelines with respect to design parameters affecting drift region's electric field and gate-stack in presence of surface traps or varying surface trap concentration is presented.