InAlN/AlN/GaN HEMTs on sapphire substrate

High quality InAlN/AlN/GaN heterostructure is grown by metal organic chemical deposition (MOCVD) on sapphire substrate. A high two-dimensional electron gas (2DEG) density of 2.5×10¹³ cm^-2 was measured in this structure. To character the electric property of this heterostructure, a 1-μm-long gate InAlN/AlN/GaN high-electron mobility transistors (HEMTs) were fabricated. A maximum output current density of 1.19 A/mm and a peak extrinsic transconductance of 240 mS/mm were measured with the InAlN/AlN/GaN HEMTs. Compare to the normal AlGaN/AlN/GaN HEMTs, the maximum current density and transconductance is greatly improved due to the high 2DEG density and thin barrier layer.