Samples of p-type material were implanted with 20keV 2H+ or 30keV 7Li+ ions, in order to form a diffusion source, and were then annealed (vacuum, 400 to 700C, 0.25 to 16h). Secondary ion mass spectrometry was used to measure the D and Li distributions after heat treatment. Both D and Li decorated bombardment-produced defects in the vicinity of the ion implantation profile. They were also trapped, usually by residual B impurities, during diffusion into the bulk. An effective diffusion coefficient, with an activation energy of 2.1eV, was deduced for Li diffusion in p-type 6H-SiC. This reflected the dissociation of trapped Li. The capture radius for D trapping, probably by B, was estimated to be 1nm.

Diffusion of Light Elements in 4H- and 6H-SiC. M.K.Linnarsson, M.S.Karlsson, A.Schoner, N.Nordell, B.G.Svensson: Materials Science and Engineering B, 1999, 61-62, 275-80