Low-Temperature ICP-CVD SiN<italic>x</italic>as Gate Dielectric for GaN-Based MIS-HEMTs

Abstract

SiN x deposited by inductively coupled plasma chemical vapor deposition (ICP-CVD) technique at low temperature (70 °C) was investigated as gate dielectric for AlGaN/GaN metal–insulator–semiconductor high electron mobility transistors (MIS-HEMTs). Besides significant reduction in gate leakage current, the MIS-HEMTs showed improvement in drain current characteristics, 2DEG channel mobility, $I_{\mathrm{\scriptscriptstyle ON}}/I_{\mathrm{\scriptscriptstyle OFF}}$ ratio, ON-resistance, and three terminal breakdown voltage as compared with reference HEMTs. Very small capacitance–voltage hysteresis (~68 mV) was observed for a gate swing of −10 to +5 V. The effect of SiN x thickness ( $t_{\mathrm {SiN}x}$ ) on the characteristics of MIS-HEMTs was studied. The performance of fabricated MIS-HEMTs was found to be stable for a wide range of temperature.