Carbon-cap for ohmic contacts on n-type ion implanted 4H-SiC

In this study a pyrolyzed photoresist film that has been used for protecting the implanted surface of a 4H-SiC wafer during post implantation annealing at 1800-1950 degrees C has preserved on the wafer surface and used for the fabrication of ohmic contact pads on P(+) implanted areas. The carbon film has been patterned by using a RIE O(2)-based plasma. A specific contact resistance of 9 x 10(-5) Omega cm(2) has been obtained on P(+) 1 x 10(20) cm(-3) implanted 4H-SiC. Micro-Raman characterizations show that the carbon cap is formed of a nano-crystalline graphitic phase.