Effects of C or Si co-implantation on the electrical activation of B atoms implanted in 4H-SiC

The influence of co-implantation of C or Si ions on the electrical activation of B accepters in 4H-SiC was studied by using Hall effect and photoluminescence (PL) investigations. The free hole concentration in B-implanted layers is found to increase due to co-implantation of C and to decrease owing to Si co-implantation, Hot co-implantation of C at 800 degrees C gives rise to a further increase of the free hole concentration. It is found that the intensity of the PL peak at a wavelength 383.9 nm, which arises from shallow B accepters [Sridhara et al., Mater. Sci. Forum 264-268, 461 (1998)], is enhanced by the coimplantation of C. These results demonstrate that the electrical properties of B-implanted p-type layers are improved by C co-implantation. The mechanisms, which alter the electrical activation of implanted B atoms due to co-implantation of C or Si, are discussed. (C) 1998 American Institute of Physics. [S0003-6951(98)02036-1].