Rapid thermal annealing (RTA) of 4H-silicon carbide (SiC) is investigated for the activation of Al implanted layers. The lowest sheet resistances achieved for an Al doping of 1(.)10(15)cm(-2) were about 60kOmega/rectangle for an annealing time of 300s at a temperature of 1700degreesC. Additionally, atomic force measurements (AFM) show smooth surfaces. The root mean square (rms) roughness remains below 1 nm for doping concentrations up to 1(.)10(14)cm(-2). pn-diode test structures were fabricated with different edge terminations and were electrically characterized. With an implant dose of 2(.)10(13)cm(-2) for edge termination, breakdown voltages higher than 1500V were achieved.