Demonstration of Normally-OFF recessed MIS-Gate technique on AlGaN/GaN HEMT for improved power dissipation

Abstract

AlGaN/GaN heterostructures based High Electron Mobility Transistors (HEMT’s) are normally-on devices. However, normally-off operation is desirable in many applications ofpower electronics. The recessed gate technique for GaN based HEMT with stacked passivation pattern has been designed for normally-off operation. The high threshold voltage is achieved by using a GaN based metal insulator semiconductor recessed gate structure with highly polarised charges under the gate. Stacked passivation is effective in spreading electric field and enhancement in breakdown voltage. The physical simulator Technology Computer Aided Design (TCAD) is used to analyse and simulate the HEMT. Numerous physics-based models are used to calibrate the simulation. The simulation results show the IDS-VGS characteristics, ION/IOFF, and threshold voltage (VTH) of MIS recessed gate AlGaN/GaN HEMT. To further solidify the analysis, gate length has been increased from 500 nm to 900 nm. In future device can be used for various sensor applications.