Comparison of ohmic contact properties on n-GaN/p-SiC and n-AlGaN/p-SiC heterojunctions

Luo B; Kim J; Mehandru R; Ren F; Lee KP; Pearton SJ; Polyakov AY; Smirnov NB; Govorkov AV; Kozhukhova EA; Osinsky AV; Norris PE

Solid-State Electronics, Vol.46, No.9, 1345-1349, 2002

DOI10.1016/S0038-1101(02)00066-7 Export Citation

Comparison of ohmic contact properties on n-GaN/p-SiC and n-AlGaN/p-SiC heterojunctions

Luo B, Kim J, Mehandru R, Ren F, Lee KP, Pearton SJ, Polyakov AY, Smirnov NB, Govorkov AV, Kozhukhova EA, Osinsky AV, Norris PE

GaN/SiC and Al0.5Ga0.75 N/SiC heterojunction diodes were fabricated using Al/Ti for p-ohmic contact to the SiC and Ti/Al/Pt/Au for n-ohmic contact to the GaN and AlGaN. Annealing at 850 degreesC for 20 s (GaN) or 120 s (AlGaN) was required for achieving specific contact resistances in the 10(-6) Omega cm(2) range. The reverse breakdown voltage showed a negative temperature coefficient in both types of sample. with value similar to5.5 +/- 2.5 x 10(-3) V/K. The I-V characteristics of both heterojunctions show evidence of tunneling via defect states. (C) 2002 Published by Elsevier Science Ltd.