The selective diffusion of B in 6H-type material was studied. Photoluminescence spectroscopy, scanning electron microscopy cathodoluminescence imaging, secondary-ion mass spectroscopy, optical microscopy and the stain-groove technique were used to characterize selectively-doped regions which were prepared by diffusion from the vapour phase and through a graphite mask. Local p-doped regions, with dimensions as small as some 20μm in diameter, were formed on n-type substrates by using a graphite mask. The maximum concentration of B atoms at the surface, as measured by secondary ion mass spectrometry, varied from 3 x 1019 to 6 x 1019/cm3; depending upon the diffusion temperature. The p-n junction depth, as measured by using the stain-groove technique, varied from 0.5 to 1.2μm.

Boron Diffusion into 6H-SiC through a Graphite Mask. S.Soloviev, Y.Gao, X.Wang, T.Sudarshan: Journal of Electronic Materials, 2001, 30[3], 224-7