DC and RF analysis of ScAlN/GaN/β-Ga2O3 and ScAlN/InGaN/GaN/β-Ga2O3 HEMTs on SiC Substrate

Abstract

Scandium aluminum nitride (ScxAl1-xN) is a promising material among group III nitrides, offering outstanding polarization properties resulting in very large carrier densities. We report the comparative analysis of Sc0.18Al0.72N/GaN/β-Ga2O3 and Sc0.18Al0.72N/InGaN/GaN/β-Ga2O3 HEMTs on Silicon carbide substrate. LG = 55 nm, Sc0.18Al0.72N/GaN/β-Ga2O3 HEMT demonstrated maximum current density (IDS) of 4.38 A/mm, very large carrier density (ns) of 2.34×1013 cm-2, large breakdown voltage (74 V) with low on-resistance (Ron ∼ 0.2 Ω.mm), and cut-off frequency (fT) /maximum oscillation frequency (fmax) of 220/242 GHz. Introduction of a very thin 5 nm In0.1Ga0.9N layer in the channel, further improves the 2DEG (two-dimensional electron density), drain current, breakdown voltage. Furthermore, Sc0.18Al0.72N/InGaN/GaN/β-Ga2O3 heterostructure shows stable transconductance (gm) over wide gate bias. A gate voltage swing (GVS) of 7.72, IDS of 6.08 A/mm, and VBR of 105 V with Ron ∼ 0.138 recorded. These findings show the merits of scandium aluminium nitride barrier material, which enables the HEMTs for next generation radar and telecommunications.