High-Performance Normally Off p-GaN Gate HEMT With Composite AlN/Al_0.17Ga_0.83N/Al_0.3Ga_0.7N Barrier Layers Design

Abstract

In this paper, a novel normally off p-gallium nitride (GaN) gate high electron-mobility transistor (HEMT) with composite AlN/Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.17</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.83</sub> N/Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</sub> N barrier layers is proposed. Compared to the standard (STD) p-GaN/AlGaN/GaN HEMT structure, the composite barriers (CB) with AlN etchstop layer can effectively improve the uniformity of the device threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ) and reduce the leakage current. The CB p-GaN gate HEMT achieved a V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> of 1.7 ± 0.06 V; this value was 2.1 ± 0.2 V for STD HEMT. In addition, the off-state drain leakage current was suppressed one order of magnitude by adopting a composite barrier design.