Effects of p-GaN Body Doping Concentration on the ON-State Performance of Vertical GaN Trench MOSFETs

In this letter, we report the influence of p-GaN body doping concentration on the ON-state performance of vertical GaN trench MOSFETs. Decreasing the p-GaN body doping concentration leads to an enhanced maximum drain current (ID,max), reduced specific ON-resistance (RON,sp), but also a decreased threshold voltage (Vth), suggesting that the p-GaN doping plays an important role in balancing the Vth, RON,spand ID,maxin vertical GaN trench MOSFETs. Resulting from the tuning of Mg concentration in the p-GaN, we demonstrate high ON-performance including a high ID,maxof 2.8 kA/cm2, a low RON,spof 0.87 mΩ·cm2, a large Vthof 4.8 V in a quasi-vertical GaN trench MOSFET on sapphire with a 2.5- μm-thick drift layer, while maintaining a breakdown voltage of 273 V.