Structural defects in sublimation-grown layers were investigated by using transmission electron microscopy, atomic force microscopy, X-ray topography and KOH etching. The nucleation of 2-dimensional islands on damage-free surfaces of high-quality Lely seeds led to the formation of stacking faults in the initial stages of growth. The location and number of stacking faults was related to the threading dislocation density. The growth rate was shown to have a marked effect upon the threading dislocation densities. The elementary screw dislocation density was observed to increase from 20 to 4000/cm2 when the growth rate was increased from 0.02 to 1.5mm/h. Growth on seeds that were mis-cut 5° off the c-axis resulted in screw dislocation densities that were almost 2 orders of magnitude lower than those for on-axis growth. The results were explained in terms of stacking disorder in the initial stages of growth.

Nucleation of Threading Dislocations in Sublimation Grown Silicon Carbide. E.K.Sanchez, J.Q.Liu, M.De Graef, M.Skowronski, W.M.Vetter, M.Dudley: Journal of Applied Physics, 2002, 91[3], 1143-8