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 19 μ s 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.