SYMMETRY CONSTRAINTS AND EPITAXIAL-GROWTH ON NON-ISOMORPHIC SUBSTRATE

Symmetry considerations discussed in the paper enable one to determine the constraints on single crystal growth in deposition on non-isomorphic substrates. Curie's law of symmetry is applied to the two-dimensional point symmetries of interfaces. The procedure described in the paper allows one to draw strict conclusions about the possibility of single-crystal growth and the crystallographic orientation of the epilayer. An analysis of three heteroepitaxial systems - A(3)B(5) nitride on sapphire, silicon on sapphire and A(3)B(5) on spinel - serves to illustrate the theoretical approach. The results of this analysis generally agree with data published earlier. Possible causes of the discrepancies are discussed. It is shown that geometrical match is not the governing factor as far as epitaxy on non-isomorphic substrates is concerned.