In-situ-SiN/AlN/Al_0.05Ga_0.95N High Electron-Mobility Transistors on Si-Substrate Using Al₂O₃/SiO₂ Passivation

Abstract

In this study, in-situ MOCVD-grown SiN/AlN/Al0.05Ga0.95N HEMTs were fabricated using ALD-Al2O3/PECVD-SiO2 passivation. A high on/off current ratio of 109 and a low subthreshold swing of 64 mV/dec are achieved. The interface traps in the SiN/AlN/Al0.05Ga0.95 N structure are investigated using frequency-dependent capacitance-voltage and conductance measurements. The shift in threshold voltage, under a gate-bias stress of 4 V for 1000 s, is less than 0.06 V for the devices with 3 nm in-situ SiN as gate dielectric. This indicates excellent bias-induced threshold-voltage stability. A saturated drain current of 6.4 A, a specific on-resistance of 5.37 $\text{m}\Omega \cdot $ cm2, and a high breakdown voltage of 1014 V are observed for the devices with a gate width of 20 mm. Baliga’s figure of merit for the devices reaches $1.91\times 10^{8}\,\,\text{V}^{2}\Omega ^{-1}$ cm−2, which confirms its potential for high-power-switching applications.

Keywords

• AlN/AlGaN heterostructure
• in-situSiN
• Al₂O₃/SiO₂ passivation
• high-power application