Al0.25Ga0.75N/GaN HFETs grown on a sapphire substrate were fabricated using an RuO2 based Schottky contact. The Schottky contact characteristics for various gate metals, such as RuO2/Au, Pt/Au, Ni/Au, and Ni/Pt/Au, were compared, and showed that the RuO2/Au metal scheme was superior to the others. RuO2-gated AlGaN/GaN HFETs with a 220 Å and 270 Å-thick Al0.25Ga0.75N layer exhibited a maximum drain current of 689 and 808 mA/mm at VGS = +1 V, respectively. An HFET with a 220 Å-thick Al0.25Ga0.75N layer exhibited a current gain cut-off frequency of 27 GHz and maximum oscillation frequency of 46 GHz for a gate length of 0.8 μm. The RF output power density for the device was 1.12 W/mm at 1.8 GHz.
|Journal||Journal of the Korean Physical Society|
|Issue number||SUPPL. Part 1|
|Publication status||Published - 2001 Dec|
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)