In-situ-SiN/AlN/Al0.05Ga0.95N High Electron-Mobility Transistors on Si-Substrate Using Al2O3/SiO2 Passivation

In this study,
in-situ
MOCVD-grown SiN/AlN/Al
_0.05
Ga
_0.95
N HEMTs were fabricated using ALD-Al
₂
O
₃
/PECVD-SiO
₂
passivation. A high on/off current ratio of 10
⁹
and a low subthreshold swing of 64 mV/dec are achieved. The interface traps in the SiN/AlN/Al
_0.05
Ga
_0.95
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 $
cm
²
, 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.