Room-Temperature Organic Passivation for GaN-on-Si HEMTs With Improved Device Stability

In this work, we report an effective room-temperature passivation strategy for GaN-on-Si high-electron-mobility transistors (HEMTs) to improve device stability by introducing a spin-coated CYTOP organic passivation layer. This CYTOP coating can suppress the interface states of the devices to a low level of
$\sim 10^{{12}}$
cm
$^{-{2}}\cdot $
eV
$^{-{1}}$
at a shallow energy trap of
$\sim $
0.30 eV. As a result, improved device stability is realized, featuring reduced leakage current, smaller voltage hysteresis, reduced current collapse, and mitigated device degradation after long-term electrical stress. Besides, it is found that the CYTOP-passivated HEMT can operate with stable rectification behavior under an elevated temperature of 250 °C, confirming the high-temperature robustness of this organic passivation. These results highlight the potential of such room-temperature passivation strategy for further applications in electronic systems under complex conditions and harsh environments.