Design of E-mode GaN HEMTs by the Polarization Super Junction (PSJ) technology

摘要

In this paper, a normally-OFF high voltage GaN HFETs based on the Polarization Super Junction (PSJ) concept has been presented. In this new device, threshold voltage (VTH) can be controlled by adjusting the etching depth of the recessed region without modifying on-resistance (RON) characteristics. The threshold voltage of E-mode device increased to 2 V while the threshold voltage for experimental D-mode structure was about -4 V. The challenge of achieving high breakdown voltage (BV) with minimum on-resistance has been addressed by the lateral scaling of recessed region to achieve an improved figure of merit (FOM). The specific on resistance of the proposed E-mode PSJ HFET is maintained low while the BV of the device increases from 560 V to 800 V of the D-mode PSJ HFET with the same dimensional parameters.