Effects of notch structures on DC and RF performances of AlGaN/GaN high electron mobility transistors* *Project supported by the National Natural Science Foundation of China (Grant Nos. 61674117 and 61974108) and the State Key Discipline Laboratory ofWide Bandgap Semiconductor Technology of Xidian University, China.

Abstract

The effects of various notch structures on direct current (DC) and radio frequency (RF) performances of AlGaN/GaN high electron mobility transistors (HEMTs) are analyzed. The AlGaN/GaN HEMTs, each with a 0.8-μm gate length, 50-μm gate width, and 3-μm source–drain distance in various notch structures at the AlGaN/GaN barrier layer, are manufactured to achieve the desired DC and RF characteristics. The maximum drain current (I ds,max), pinch-off voltage (V th), maximum transconductance (g m), gate voltage swing (GVS), subthreshold current, gate leakage current, pulsed I–V characteristics, breakdown voltage, cut-off frequency (f T), and maximum oscillation frequency (f max) are investigated. The results show that the double-notch structure HEMT has a 30% improvement of gate voltage swing, a 42.2% improvement of breakdown voltage, and a 9% improvement of cut-off frequency compared with the conventional HEMT. The notch structure also has a good suppression of the current collapse.