In 4H-SiC electronic devices, Al+ ion implantation is often used to obtain selected regions of desired p-type conductivity in n-type epitaxial layers. A mandatory high temperature annealing is necessary after the implantation process for the electrical activation of the implanted Al. The temperature of the former and the density of the latter vary in the range 1600-1950°C and 1017-1020 cm-3, respectively. The switching properties of the so obtained bipolar junctions depend on carrier life-time in the n-type 4H-SiC epitaxial layers after processing. In the literature, it has been shown that carbon vacancy VC in n-type 4H-SiC epi-layers is a carrier life-time killer defect and that its concentration, after high temperature treatments in the range 1500-1950°C, saturates on values that are higher the higher are the applied temperature and cooling rate [1]. It has been also shown that, in the case the thermally treated 4H …