AlGaN/GaN MOS-HEMTs-on-Si employing sputtered TaN-based electrodes and HfO2 gate insulator

We report on a low specific on-resistance (R-on,R-sp) of 3.58 m Omega-cm(2) and a high breakdown voltage of 1.4 kV in a CMOS-compatible AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT). The MOS-HEMT is on a Si substrate and uses TaN electrodes and a HfO2-gate insulator. The sputtered TaN - a substitute for Au that has low resistivity, high work function, and thermal stability - was applied at room temperature to the gate, source, and drain. In order to obtain a low R-on,R-sp and high breakdown voltage, sputtering power and post-annealing temperature were optimized by measuring the characteristics of TaN. Using optimized conditions, a sputtering power of 50 W, and an annealing temperature of 880 degrees C, we successfully achieved a high on/off current ratio of 6 x 10(9) for the proposed AlGaN/GaN MOS-HEMT at a gate-drain distance of 10 mu m. These results indicate that the TaN process is a promising technique for power-switching GaN devices with CMOS compatibility. (C) 2014 Elsevier Ltd. All rights reserved.