Evaluation of ohmic contacts to p-type 6H-SiC created by C and Al coimplantation

A comparative study of specific contact resistance and sheet resistivity of p-type 6H-SiC created by Al implantation only and by C and Al coimplantation into n(-)-6H-SiC epilayer grown on n(+)-6H-SiC has been performed to address the challenging issue of ohmic contacts to the anode of SIC thyristors and other thyristor-based advanced devices. Direct experimental evidence has been obtained which shows the obvious advantage of C and Al coimplantation in terms of contact resistance and sheet resistivity, Under our experimental conditions, it is found that the specific contact resistance can be reduced by three orders of magnitude and the sheet resistivity can be improved by a factor of 6 when C and Al are coimplanted into 6H-SiC.