The sub-surface damage generated by mechanical polishing of SiC wafers was investigated and quantified by plan-view transmission electron microscopy and atomic force microscopy. Damage generated during polishing using diamond abrasives with 0.5µm particle size consists of dislocation loops with length up to 400nm from the scratches. The total dislocation density was estimated at 5 x 1010/cm2. Transmission electron microscopic analysis of the Burgers vectors indicated that the initial perfect dislocations had a Burgers vector of b = a/3<1–20>type with many dislocation dissociated into two partials with b = a/3<¯100> The depth of damage was estimated to be up to 50nm. 4H–SiC homoepitaxial layers grown on mechanically polished substrates without further surface treatment exhibited threading dislocation density along scratches in the order of 105/m.

Transmission Electron Microscopy Analysis of Mechanical Polishing-Related Damage in Silicon Carbide Wafers. J.R.Grim, M.Benamara, M.Skowronski, W.J.Everson, V.D.Heydemann: Semiconductor Science and Technology, 2006, 21, 1709-13