Electrical characterization of p-type 6H-SiC layers created by C and Al co-implantation

Advantages of C plus Al co-implantation for p-type doping have been studied comparatively to Al single implantation in 6H-SiC with Al concentrations ranging from 8 x 10(19) to 2 x10(21)cm(-3). Dramatic reductions are observed in specific contact resistance of Al ohmic contacts made to the C-Al co-implanted layers with the lowest resistance in the range of low 10(-5) Omega cm(2). The advantage over Al single implantation depends on Al concentration and reaches three orders cif magnitude at an Al concentration of 6 x 10(20) cm(-3). Associated reductions in sheet resistivity are also, observed. Hall-effect measurement shows that room-temperature conductivity is dominated by impurity-band conduction, indicating enhancement of acceptor activation efficiency by C and AL co implantation.