Raman scattering as a probing method of subsurface damage in SiC

The subsurface damage extension has been investigated in 4H- and 6H-SiC as a function of the size of the polishing abrasive powder. Raman scattering s pectra have been collected in the transverse ki//ks perpendicular toc confi guration and, from an analysis of the high-frequency longitudinal phonon-pl asmon coupled mode, the free carrier density has been evaluated at differen t distances beneath the sample surface. II was found that the variation of the carrier density depends strongly on the size of the polishing slurry, M oreover, comparing 6H- and 4H-SiC it was found that, for a given slurry 4H- SiC damaged is deeper than 6H-SiC. (C) 2001 Elsevier Science B.V. All right s reserved.