A FAST X-RAY-DIFFRACTION METHOD FOR THE SURFACE ORIENTATION ANALYSIS OF LARGE POLYCRYSTALLINE SAMPLES

A crystallographic orientation analysis to study heterogeneous polycrystalline samples is reported. A specific arrangement was realized to explore the total surface of large wafers or ribbons without destructive sampling. The surface texture is determined by X-ray diffraction using reflection geometry. Approximate size and orientation of crystallites at the sample surface are evaluated from a method taking iterative comparisons of intensities as a basis. For each explored (hkl) pole, two intensities are measured by reflection on the surface element studied: the first when the reflective surface is fixed at the (hkl) Bragg angle; the second when the surface is rocked around this position. The same measurements, obtained from an even surface of (hkl) monocrystals, provide calibration curves. Generally the exploration of five or six different (hkl) poles is enough to obtain a valid description of polycrystalline silicon materials elaborated for photovoltaic conversion.