Study of High-Performance GaN-Based Trench CAVET with Stepped Doping Microstructure

In this article, an innovative GaN-based trench current-aperture vertical electron transistor (CAVET) with a stepped doping microstructure is proposed and studied using Silvaco-ATLAS. According to the simulation and analyzed characteristics, the best performance renders a remarkable Baliga’s figure of merit (FOM) of 4.767 GW·cm(2) owing to the modulation of the electric-field distribution. By adjusting the size of the stepped doping microstructure and doping concentration in the GaN drift, the maximum optimized result can achieve a relatively high breakdown voltage (BV) of 2523 V with a very low specific on-resistance (R(on,sp)) of 1.34 mΩ·cm(2), or the BV can be improved to 3024 V with a specific on-resistance (R(on,sp)) of 2.08 mΩ·cm(2). Compared with the conventional superjunction GaN-based trench CAVET, the newly demonstrated structure can achieve a 43% reduction in R(on,sp) and increase by almost 20% the original BV. These results indicate the superiority of using the stepped doping microstructure in a trench CAVET to improve the BV and decrease R(on,sp), providing a reference for further development of GaN-based CAVETs.