摘要:

A novel early gate dielectric AlGaN/GaNmetal–insulator–semiconductorhigh-electron-mobilitytransistors (MIS-HEMTs) process is reported. With the highqualitySi3N4 dielectric by low-pressure chemical vapordeposition and damage free, self-terminating passivationlayer etching at the gate area, the MIS-HEMTs on 150-mmSi substrate demonstrate excellent output performanceand good uniformity. The interface trap density betweenthe gate insulator and the barrier layer is as low as2 × 1012 cm−2 · eV−1 extracted by the conductancemethod. The MIS-HEMT fabricated on the wafer delivers anextremely small gate leakage current of 10−9 mA/mm anda high Ion/Ioff ratio of 1011. The subthreshold swing (SS) isaround 80mV/dec, and the saturated output current densityis 750 mA/mm. The dynamic on-resistance increases about42% at a quiescent drain bias of 600 V. The Vth shift is−0.63 and −0.89 V at a high temperature of 200 °C andnegative gate-bias stress of −25 V, respectively, indicatinga comparable stability with the state-of-the-art MIS-HEMTs.An excellent threshold voltage and SS uniformity (1 − σ/μ)with the value of 94.5% and 95.2% are achieved on the150-mm wafer.

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