Optimization of enhancement mode P-type Mg-doped In0.2Ga0.8N cap gate DH-HEMT for low-loss high power efficient boost converter circuits

In this paper, Al0.23Ga0.77N/GaN/Al0.05Ga0.95N Double Heterostructure-High Electron Mobility Transistor targeting a low loss and high power efficient boost converter circuit was simulated using a thin P+In0.2Ga0.8N cap under the gate. The charge balancing concept of the polarization induced field of the device was due to the Mg-doped P+In0.2Ga0.8N which shows normally-off characteristics. The high positive threshold voltage VT shift achieved with the device was correlated with the obtained dynamic RON of the device. This dynamic RON was characterized 19μs immediately after the device was turned-on and goes up to a maximum of 550 V. Furthermore, this Al0.23Ga0.77N/GaN/Al0.05Ga0.95N demonstrates low dynamic RON of ~6% with increment of efficiency of up to 40% when measured in the booster converter circuit. For power switching applications, the result of this P+In0.2Ga0.8N cap having a back-barrier/buffer of AlGaN achieved a dynamic RON performance with excellent breakdown Voltage VBR.OFF and much lower OFF-state gate/drain leakage as compared to the conventional GaN buffer structures.