A non-destructive low-temperature supercritical nitridation (LTSCN) is proved to boost the performance of AlGaN/GaN HEMTs. The samples were treated at 120 ℃ in a supercritical CO₂ fluid mixed with NH₃ under 20.7 MPa for one hour. After the LTSCN, the gate leakage current decreases by 69.6 % for an increase of the Schottky barrier height and the subthreshold swing is reduced by 19.9 %. Furthermore, the on-resistance is reduced by 20.4 % due to an enhancement of the mobility. The slow trap state density near AlGaN/GaN interface decreases from (5.12×10¹³ to 7.07×10¹³) cm⁻²·eV⁻¹ to (1.80×10¹³ to 2.36×10¹³) cm⁻²·eV⁻¹ with a decrease in activation energy from (0.492 to 0.500) eV to (0.467 to 0.496) eV after the LTSCN. A modified model of the LTSCN is presented to expound the change of the slow traps and the Coulomb scattering effect of electrons capture in the changed slow traps is adopted to explain the mobility improvement.

事实证明，无损低温超临界氮化（LTSCN）可提高AlGaN / GaN HEMT的性能。在20.7 MPa的超临界CO ₂和NH ₃混合液中，将样品在120℃下处理1小时。在LTSCN之后，由于肖特基势垒高度的增加，栅极漏电流减小了69.6％，亚阈值摆幅减小了19.9％。此外，由于迁移率的提高，导通电阻降低了20.4％。AlGaN / GaN界面附近的慢势阱态密度从（5.12×10 ¹³减小到7.07×10 ¹³）cm ^-2 ·eV ^-1到（1.80×10 ¹³减小到2.36×10 ¹³）cm ^-2·eV ^-1，其活化能从LTSCN之后的（0.492降至0.500）eV降至（0.467至0.496）eV。提出了改进的LTSCN模型，以解释慢陷阱的变化，并采用电子库仑散射效应来解释迁移率的提高，电子在变化的慢陷阱中被俘获。