E-mode p-n Junction/AlGaN/GaN (PNJ) HEMTs

in this work, we demonstrate a GaN-based p-n junction gate (PNJ) HEMT featuring an n-GaN/p-GaN/AlGaN/ GaN gate stack. Compared to the more conventional p-GaN gate HEMT with a Schottky junction between the gate metal and p-GaN layer, the p-n junction can withstand higher reverse bias at the same peak electric-field as the depletion region extends to both the n-side and p-side, while exhibiting lower leakage current. The PNJ-HEMT shows a positive threshold voltage (VTH) of 1.78 V, a small gate leakage (~10-3 mA/mm @ VGS = 10 V). In particular, a large forward gate breakdown voltage of 19.35 V at 25 ℃ and 19.70 V at 200 ℃ was achieved with the PNJ-gate HEMT.