Abstract
An x-ray stress measuring method for a single crystal is proposed. This method can be applied to a orthorhombic single crystal having x, y and z crystal symmetry planes, the x-y plane being the specimen surface. In the plane stress state, residual stresses σ0x and σ0y can be determined using slopes M and M' of sin2ψ diagrams for the x and y measurement directions. Various stresses σa were applied to a silicon single crystal wafer specimen in longitudinal (x) direction using a four points bending loading device, and the peak positions of different diffraction planes were measured in the x and y directions by x-ray diffraction method. The measured peak positions of diffraction planes were plotted in the sin2ψ diagram for various applied stresses σa. Although the peak positions of different planes in the sin2ψ diagram deviated from the straight lines determined by the least squares method, the straight lines crossed at a point, and the slopes and intercepts of the straight lines varied linearly with the applied stress σa. The peak positions for a fixed ψ angle varied proportionally to the applied stress σa, and the measured proportionality constants ki and k'i in the x and y directions, respectively, almost agreed with the theoretical values.
