Abstract
We have demonstrated significant improvements of AlGaN/GaN High Electron Mobility Transistors (HEMTs) dc performance by employing Pt/Ti/Au instead of the conventional Ni/Au gate metallization. During off-state bias stressing, the typical critical voltage for HEMTs with Ni/Au gate metallization was ~ -45 to -65V. By sharp contrast, no critical voltage was observed for HEMTs with Pt/Ti/Au gate metallization, even up to -100V, which was the instrumental limitation in this experiment. After the off-state stressing, the drain current of Ni/Au gated-HEMTs decreased by~ 15%. For the Pt-gate HEMTs, no degradation of the drain current occurred and there were minimal changes in the Schottky gate characteristics for both forward and reverse bias conditions. The HEMTs with Pt/Ti/Au metallization showed an excellent drain on/off current ratio of 1.5×108. The on/off drain current ratio of Ni-gated HEMTs was dependent on the drain bias voltage and ranged from 1.2×107 at Vds=5V and 6×105
