Ohmic characteristics of Pt and Ni/Au on Mg-doped AlxGa1-xN

Mg-doped AlxGa1-xN is grown by metal-organic chemical vapor deposition to investigate the Ohmic characteristics of Pt and Ni/Au. The Al solid composition measured by x-ray varies from 0.04 to 0.19, while the atomic concentration of Mg confirmed by secondary ion mass spectroscopy spans from 3x1019 to 1x1020 cm-3. The Ohmic characteristics are measured by current-voltage by varying the Mg activation temperature, Ohmic metal annealing temperature, and annealing time. The specific contact resistance is 3.5 and 7.5x10-5 Ω cm2.with Pt and Ni/Au in p-Al0.085Ga0.915N and p-Al0.14Ga0.86N measured by circular transmission line model, respectively. These are the lowest ever reported in p-AlGaN.