Al⁺ ion implanted on-axis <0001>semi-insulating 4H-SiC

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 4.7×10, 9.3×10, and 4.7×10 cm, 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.