A novel AlGaN/GaN/AlGaN double-heterojunction high electron mobility transistor for performance improvement

In this paper, we present an enhancement of breakdown voltage in AlGaN/GaN/AlGaN double-heterojunction high-electron-mobility-transistor devices by introducing a magnesium doping layer in AlGaN buffer layer under the 2DEG channel. The optimized electron confinement and mitigated electric field peak under the drain side of the gate in DH-HEMT along with more evenly distributed electric field due to the presence of a charge balanced magnesium doping layer result in significant breakdown voltage improvement and subthreshold gate and drain leakage currents suppression. The introduced magnesium doping layer acts as a floating field plate. By optimizing the length of this float field plate, the breakdown voltage will increase by 90.5%, which is very important in higher voltage applications. This approach also allows a 33% decrease of the peak electric field under the drain side edge of the gate while the ON-state resistance is negligibly increased.