P-type 4H-SiC layers have been obtained by different 400 C Al+ ion implantation processes of semi insulating 4H-SiC wafers and identical 1950 C/5 min post implantation annealing. Implanted Al+ concentration have been 4.7× 1018, 9.3× 1018, and 4.7× 1019 cm-3, thickness of the implanted layer about 630 nm. Electrical characterizations have been performed in the temperature range 100–580 K. With decreasing temperature, the onset of a hole conduction through an impurity band has been seen for all the specimens.