Patent ID: 7769135

Claim:
A method for X-ray diffraction XY mapping of the distribution crystal forms and defects across a semiconductor wafer comprised of rhombohedrally aligned group IV, group III-V, or group II-VI materials, or alloys thereof, on the (0001) c-plane of trigonal or hexagonal crystal substrate, said method comprising: a) providing a point or line X-ray source; b) setting the detector angle (2θ) to the angle of a (440) peak of said rhombohedrally aligned material; c) setting a sample tilt angle, ψ(or χ) of approximately 0; d) calculating the inter-planar angle (τ) between the (111) plane of said rhombohedrally aligned material and said (440) plane; e) setting the goniometer angle Ω approximately equal to θ+τ, where θ is the half of detector angle (2θ); f) performing a Phi(φ)-scan to find (440) peaks of single crystal and 60° rotated twin defects; g) setting the Phi(φ) angle to a desired peak; and h) moving the sample wafer in X and Y directions and recording the intensity of diffracted X-rays at the various positions of said movement.