Patent ID: 7558371

Claim:
A method of generating X-ray diffraction data suitable for twin defect detection in a lattice-matched or strained epitaxial material, said epitaxial material comprising a first component having a first crystal structure, said first component being lattice matched or strained to a second component having a second crystal structure, wherein said first crystal structure has either (i) a <111> orientation relative to said second crystal structure and a {111} crystal plane normal thereto, or (ii) a {111} crystal plane at an interface of said first crystal structure with said second crystal structure and a <111> vector normal thereto, said method comprising the steps of: a) designating a crystal plane of said first component that is non-perpendicular to said {111} crystal plane and that produces diffraction when impinged by an X-ray beam; b) calculating a Bragg angle θ B for said designated crystal plane; c) mounting said epitaxial material in an X-ray diffraction (XRD) system having an X-ray source for generating an X-ray beam that can impinge on said epitaxial material at a goniometer angle Ω and thereby generate X-ray diffraction, a detector having a focused direction for detecting X-ray diffraction therealong at a detector angle measured with respect to the X-ray beam, and a sample holder with a reference orientation defined thereby, wherein, when said epitaxial material is positioned in said sample holder, said [111] vector makes an angle χ relative to said reference orientation and lying in the common plane defined by said X-ray beam and said direction of focus of said detector, said angle χ being equal to β, where β is the inter-planar angle between said {111} crystal plane said designated crystal plane; d) setting said goniometer angle Ω equal to θ B ; e) setting said detector angle equal to 2*θ B ; and f) measuring the X-ray diffraction at at least one azimuthal angle φ of rotation about an axis aligned with said [111] vector, while the XRD system and said epitaxial material are in the position recited in steps c, d and e, said at least one azimuthal angle φ of rotation including at least one azimuthal angle φ of rotation at which X-ray diffraction of a twin defect occurs.