Fabrication of High-Uniformity and High-Reliability Si3N4/AlGaN/GaN MIS-HEMTs With Self-Terminating Dielectric Etching Process in a 150-mm Si Foundry

Abstract

A novel early gate dielectric AlGaN/GaN metal–insulator–semiconductor high-electron-mobility transistors (MIS-HEMTs) process is reported. With the high-quality Si3N4 dielectric by low-pressure chemical vapor deposition and damage free, self-terminating passivation layer etching at the gate area, the MIS-HEMTs on 150-mm Si substrate demonstrate excellent output performance and good uniformity. The interface trap density between the gate insulator and the barrier layer is as low as $2 \times 10^{{12}}{\mathrm {cm}}^{- {2}}\,\,\cdot \,\,{\mathrm {eV}}^{- {1}}$ extracted by the conductance method. The MIS-HEMT fabricated on the wafer delivers an extremely small gate leakage current of 10−9 mA/mm and a high ${I}_{\mathrm{\scriptscriptstyle {ON}}}/{I}_{{\mathrm{\scriptscriptstyle {OFF}}}}$ ratio of 1011. The subthreshold swing (SS) is around 80 mV/dec, and the saturated output current density is 750 mA/mm. The dynamic on-resistance increases about 42% at a quiescent drain bias of 600 V. The ${V}_{ {th}}$ shift is −0.63 and −0.89 V at a high temperature of 200 °C and negative gate-bias stress of −25 V, respectively, indicating a comparable stability with the state-of-the-art MIS-HEMTs. An excellent threshold voltage and SS uniformity ( $ {1} - \sigma /\mu)$ with the value of 94.5% and 95.2% are achieved on the 150-mm wafer.