High-Performance Normally Off p-GaN Gate HEMT With Composite AlN/Al0.17Ga0.83N/Al0.3Ga0.7N Barrier Layers Design

In this paper, a novel normally off p-gallium nitride (GaN) gate high electron-mobility transistor (HEMT) with composite AlN/Al
_0.17
Ga
_0.83
N/Al
_0.3
Ga
_0.7
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
_TH
) and reduce the leakage current. The CB p-GaN gate HEMT achieved a V
_TH
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.