High-power-density InAlGaN/GaN HEMT using InGaN back barrier for W-band amplifiers

Abstract

This paper investigated the back-barrier (BB) effect for gallium nitride (GaN)-based high-electron-mobility transistors with an Fe-doped buffer and Fe-buffer + Indium gallium nitride (InGaN)-BB structure. The authors found that the Fe-doped buffer + InGaN-BB structure was effective in reducing the off-state leakage current compared to the Fe-doped buffer. Secondary-ion-mass spectrometry measurements revealed that the segregated Fe existed with peaks at ∼2 × 1017 cm−3 around the InGaN-BB layer. The authors believe that the negative charges which are generated by Fe effectively increased the BB effect as they exist just underneath the 2-dimensional-electron-gas channel and successfully achieved a high output power operation of 4.6 W/mm at 94 GHz.