Schottky-MIS Cascode Drain Reverse-Blocking p-GaN Gate Transistor With Significantly Reduced Forward Drop and Ultralow Leakage Current

Abstract

In this article, we experimentally propose a reverse-blocking (RB) p-GaN gate transistor with the Schottky-MIS cascode drain (CDT) for the significantly reduced forward voltage drop ${\textit {V}}_{\mathbf {F}}$ and ultralow reverse leakage current ${I}_{\mathbf {\textit {LEAK}}}$ . At forward bias, electron concentration at the Schottky-MIS cascode drain is higher than that at conventional p-GaN/Ohmic drain. When experiencing reverse bias, the Schottky-MIS cascode drain effectively protects the Schottky contact from the high reverse potential compared to Schottky drain. The fabricated Schottky-MIS CDT presents a superior ${V}_{\mathbf {F}}$ - ${I}_{\mathbf {\textit {LEAK}}}$ relationship including a greatly reduced ${V}_{\mathbf {F}}$ of 3.1V as well as an ultralow ${I}_{\mathbf {\textit {LEAK}}}$ of ${1}\times {10} ^{-{8}}$ A/mm, together with a competitive reverse power figure-of-merit (FOM) of 120MW/cm2. These performances suggest that the proposed Schottky-MIS CDT can be a promising candidate for low-loss RB GaN power transistors and applications requiring a better ${V}_{\mathbf {F}}$ - ${I} _{\mathbf {\textit {LEAK}}}$ trade-off.