Influence of strain on solid-liquid phase equilibrium in heteroepitaxy of SiGe/Si(0Â 0Â 1)

A heteroepitaxially grown layer with a lattice constant different from that of substrate is subject to strain. If this strain cannot be released by misfit dislocations or surface undulation a pseudomorphic strained layer with lattice relaxation in growth direction will be formed. A simple model has been outlined to involve this strain energy into liquid-solid phase equilibrium calculations. The calculations have been applied to a SiGe layer on a Si(0 0 1) substrate grown from a ternary metallic solution with bismuth as solvent. The Ge amount has been varied. An increasing germanium content in the liquid phase leads to an additional supercooling necessary to balance out the rising strain in the solid layer. Moreover, the germanium content in the solid will shift to lower values in response to strain.