Analytical model of source injection for N-type enhancement mode GaN-based Schottky source/drain MOSFET

GaN MOSFET source/drain fabrication techniques have been under extensive research, and Ion Implantation (II) and selective area regrowth (SAG) methods have shown the best performance. As an alternative for S/D of GaN MOSFETs beyond II or SAG, the use of metal for S/D of GaN MOSFETs (or Schottky barrier GaN MOSFET) has been proposed. While a Schottky metal source/drain presents several potential technological advantages, one of the greatest issues of GaN Schottky Barrier MOSFETs is that the on-state current is low compared to other GaN MOSFETs that use II or SAG for source and drain. To overcome this issue, a new device structure with gate-to-source/drain overlap was proposed. Synopsis TCAD simulation was performed on the proposed device, which indicated that the on-state current of gate-to-source overlapped device can be increased by 2 orders of magnitude compared to the one without overlap structure. This work is devoted to (1) identification of the mechanism that increases the on-state current, (2) development of an analytical model from the mechanism, and (3) physical demonstration of the simulated device.