Normally-Off p-GaN Gate AlGaN/GaN Transistor with a New Schottky Second Gate

This study presents a normally-off dual-gate AlGaN/GaN high-electron-mobility transistor. The second gate is located between the p-GaN gate and the drain and is connected to the source. The optimized thickness and length of the AlGaN layer under the second gate next to the p-GaN significantly impact the maximum drain current and the off-state breakdown conditions. The reverse conduction characteristic is also improved because the freewheeling path of the reverse current is established between the second gate and the drain to prevent excessive voltage drop and conduction losses when the device is negatively biased. Compared with conventional HEMT, the proposed method shows a promising way to achieve normally-off GaN-based HEMTs with excellent forward ad reverse conduction performance.