Patent ID: 7906358
Filing Date: 2011-03-15
Classification: G01N

Abstract:
1. A method of forming a hetero-epitaxial crystal structure of a group IV, group III-V or group II-VI alloy on the basal (0001) plane of a trigonal crystal or hexagonal crystal substrate so as to minimize crystalline dislocation defects between the hetero-epitaxial crystal structure of the group IV, group III-V or group II-VI alloy and the trigonal crystal or hexagonal crystal substrate, said method comprising: (a) if said alloy is a type in which the trigonal arrangement of atomic sites of the {111} plane of said alloy crystal directly meets the hexagonal or trigonal coincidence lattice of atomic sites in the basal plane of said substrate without any rotation, calculating a target lattice constant (L (b) if said alloy is of a type in which the trigonal arrangement of atomics sites of the {111} plane of said alloy crystal meets the hexagonal or trigonal coincidence lattice of atomic sites in the basal plane of said substrate with a 30° rotation, calculating L (c) if said alloy is of a type in which the trigonal arrangement of atomic sites of the {111} plane of said alloy crystal directly meets the inner vertices of the hexagonal or trigonal coincidence lattice of atomic sites in the basal plane of said substrate without any rotation, calculating a target lattice constant (L (d) if said alloy to be of a type in which the trigonal arrangement of atomic sites of the {111} plane of said alloy crystal meets the inner vertices of the hexagonal or trigonal coincidence lattice of atomic sites in the basal plane of said substrate with a 30° rotation, calculating L (e) determining the respective proportions of the group IV, group III-V or group II-VI elements in said alloy by approximating L (f) growing the group IV, group III-V or group II-VI alloy on the basal (0001) plane of the trigonal crystal or hexagonal crystal substrate in the determined respective proportions to thereby form the hetero-epitaxial crystal structure on the trigonal crystal or hexagonal crystal substrate so as to minimize crystalline dislocation defects between the hetero-epitaxial crystal structure of the group IV, group III-V or group II-VI alloy and the trigonal crystal or hexagonal crystal substrate.