Simulation design of high Baliga's figure of merit normally-off P-GaN gate AlGaN/GaN heterostructure field effect transistors with junction field plates

摘要

In this paper, we conducted a numerical analysis on novel Normally-off P-GaN gate AlGaN/GaN heterostructure field effect transistors with junction field plates (JFP-HFET). The breakdown voltage (BV) was significantly improved with the introduction of the junction field plate (JFP), which can make a rectangular distribution of the electric field in the GaN channel between the gate and the drain. The highest BV of 1340 V of JFP-HFET could be achieved with the gate to the drain distance L-gd = 6 mu m, the length of the P-type region of the JFP L-p = 5.8 mu m, the thickness of the JFP T-j = 500 nm, the doping concentration of P-type region of the JFP N-p = 1 x 10(1)(7 )cm(-3), and the Al fraction of the AlGaN JFP x(Al )= 0.25. The optimum parameters of the JFP-HFET were achieved by considering both the principle of charge balance and the practical fabrication of the III-V devices. The highest Baliga's figure of merit (BFOM) 1.2 GW/cm(2) was obtained under the conditions of L-gd = 6 mu m, L-p = 5.8 mu m, T-j = 100 nm, N-p = 6 x 10(17) cm(-3), and x(Al) = 0.3. C-V, turn-on and turn-off processes revealed that the JFP-HFET showed better switching characteristics than that of the HFET with metal field plate.