Influence of Upper Channel Thickness on InAlN/GaN/InAlN/GaN Double Channel HEMT

HEMTs featuring a double heterostructure (DC-HEMTs) hold considerable promise for diverse applications, owing to their exceptional output characteristics. In this work, the influence of upper channel thickness on carrier distribution and the DC and RF characteristics of the DC-HEMTs was investigated. As the upper channel thickness decreases gradually, the 2-DEG density in the upper channel decreases, while it increases in the lower channel. These result in corresponding variations in transconductance peaks, f
T
, and f
max
. Furthermore, the varying effects of drain voltage on carrier concentration in both the upper and lower channels, introduce a novel dimension to the understanding of DC-HEMT characteristics. The observed trends offer crucial considerations for optimizing the design and performance of DC-HEMTs across various applications.