Improved performance of AlGaN/GaN HEMT by N₂O plasma pre-treatment

The influence of an N₂O plasma pre-treatment technique on characteristics of AlGaN/GaN high electron mobility transistor (HEMT) prepared by using a plasma-enhanced chemical vapor deposition (PECVD) system is presented. After the plasma treatment, the peak transconductance (g_m) increases from 209 mS/mm to 293 mS/mm. Moreover, it is observed that the reverse gate leakage current is lowered by one order of magnitude and the drain current dispersion is improved in the plasma-treated device. From the analysis of frequency-dependent conductance, it can be seen that the trap state density (D_T) and time constant (τ_T) of the N₂O-treated device are smaller than those of a non-treated device. The results indicate that the N₂O plasma pre-pretreatment before the gate metal deposition could be a promising approach to enhancing the performance of the device.