Reduction of Ohmic Contact Resistance on n-Type 6H-SiC by Heavy Doping

Ohmic contacts with low contact resistances were fabricated on n+ 6H-SiC layers grown by liquid phase epitaxy. Ni was deposited on the layers for the contact metal Ohmic characteristics were obtained on as-deposited n+ samples with carrier concentrations higher than about 5×1019 cm-3. The contact resistance was lowered by thermal annealing at 1000° C for 5 minutes. A specific contact resistance as low as 1×10-6 Ω· cm2 was fabricated on an n+ layer with a carrier concentration of 4.5×1020 cm-3. It was found that Ti/Al, which is widely used as a p-type ohmic contact metal, also made a good ohmic contact on the n+ layer.