High-performance Ku-band thin-barrier AlGaN/GaN MIS-HEMTs on Si using high-stress LPCVD-SiN passivation for low-voltage applications

Abstract

This paper reports on high-performance Ku-band AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs) on a Si substrate for low-voltage applications. Benefiting from the 7 nm thin-barrier AlGaN and the high-stress low pressure chemical vapor deposition (LPCVD) SiN passivation, a high saturation current of 1.56 A/mm, a low on-resistance of 0.87 Ω mm, and a small current collapse at 20 V drain quiescent condition of 2.1% were achieved. Enabled by the ability of LPCVD-SiN to allow the devices to withstand high-temperature conditions during gate dielectric deposition and post-deposition annealing, a 7 nm plasma-enhanced atomic layer deposition SiN was employed as the gate dielectric. The MIS-HEMTs show low leakage current and a large on/off current ratio. At 18 GHz, the devices achieve a peak power-added efficiency (PAE) exceeding 60% at a low drain voltage (Vds) range of 5–12 V. A peak PAE of 65.1% (Vds = 8 V) and a maximum output power density (Pout,max) of 3.46 W/mm (Vds = 12 V) were demonstrated, which are the highest PAE and Pout,max at the same operating voltage reported by GaN HEMTs in Ku-band. These excellent results show that the MIS-HEMTs have great potential in Ku-band low-voltage applications.