BORON IMPLANTATION AND EPITAXIAL REGROWTH STUDIES OF 6H SIC

Implantation of B has been performed into an epitaxially grown layer o f 6H SiC, at two different B concentrations, 2 x 10(16) cm(-3) and 2 x 10(18) cm(-3). Subsequently, an epitaxial layer was regrown on the B implanted layer. The samples were investigated by transmission electro n microscopy (TEM) and secondary ion mass spectrometry (SIMS). In the highly B-doped layers plate-like defects were found, associated with l arge strain fields, and an increased B concentration. These defects we re stable at the originally implanted region during regrowth and at an neal temperatures up to 1700 degrees C. In the samples implanted with the lower B concentration, no crystal defects could be detected by TEM . No threading dislocations or other defects were observed in the regr own epitaxial layer, which shows the possibility to grow a layer with high crystalline quality on B implanted 6H SiC. By SIMS, it was found that B piles up at the interface to the regrown layer, which could be explained by enhanced diffusion from an increased concentration of poi nt defects created by implantation damage in the region. B is also spr ead out into the original crystal and in the regrown layer at a concen tration of below 2 x 10(16) cm(-3), with a diffusion constant estimate d to 1.3 x 10(-12) cm(2)s(-1). This diffusion is most probably not dri ven by implantation damage, but by intrinsic defects in the grown crys tal. Our investigation shows that the combination of implantation and subsequent regrowth techniques could be used in SiC for building advan ced device structures, with the crystal quality in the regrown layer n ot being deteriorated by crystal defects in the implanted region. A de vice process using B implantation and subsequent regrowth could on the other hand be limited by the diffusion of B.