Liquid-phase epitaxy of silicon carbide was shown to be an effective technique to overgrow micropipe defects in SiC wafers prepared by the physical vapour transport technique. Growth close to thermodynamic equilibrium, e.g. low supersaturation, provides a favourable condition for effective micropipe healing. Therefore, the aim of this work was to grow epitaxial layers from strongly diluted Si-based solutions. Using the method of horizontal dipping, the dependence of micropipe elimination efficiency on Si–Ge flux composition and on the crystallographic orientation (on- and off-axis) of the SiC wafer was investigated. High-quality single crystalline SiC layers of a thickness up to 10μm were grown with the growth rate of 0.5μm/h. On off-oriented wafers, stepped growth morphology was observed independent of the melt composition. Micropipes with the diameter below 5μm were closed with an efficiency of about 80%. Scanning electron microscopic investigations as well as inspection under reflected/transmitted light did not show any specific distortion of the growth morphology at the micropipe healing place.

Micropipe Healing in SiC Wafers by Liquid-Phase Epitaxy in Si–Ge Melts. O.Filip, B.Epelbaum, M.Bickermann, A.Winnacker: Journal of Crystal Growth, 2004, 271[1-2], 142-50