Monolithic integration of GaN LEDs with vertical driving MOSFETs by selective area growth and band engineering of the p-AlGaN electron blocking layer though TCAD simulation

Based on an InGaN/GaN light emitting diode (LED) structure, monolithically integrated vertical driving metal-oxide-semiconductor field-effect transistors (MOSFETs) were designed and experimentally implemented using a selective area growth (SAG) method. A simple p-GaN/n-GaN stack was selectively regrown on top of the LED wafer to realize an n/p/n structure for the vertical MOSFET fabrication. The integrated vertical MOSFET, which can effectively modulate the injection current through the serially connected LED, exhibited high performance such as an enhancement-mode (E-mode) operation with a relatively high output current density. However, on-resistance (R-ON) degradation was observed in the fabricated vertical MOSFET at a low drain bias level (V-DS < 2 V). Through a 2D TCAD simulation, the origin of the high R-ON was revealed to be an electron barrier induced by the LED's p-AlGaN electron blocking layer (EBL). The simulation results also demonstrated that it can be improved by band engineering of the EBL.