PV Material and Device Characterization Equipment
Laue scanner is used for measuring crystal orientation on silicon samples. It can be used for measuring on industrial bricks and standard wafer sizes (typically 156×156 mm2) without any additional surface preparation.
While EBSD measures grain orientation on small areas (5×5 cm2) and requires time consuming sample preparation, Laue can scan large size samples and may be used on as-cut surfaces. The first part of the measurement is constituted by visualizing the grains, requiring some contrast between the grains for a proper grain detection. Subsequently, the grain orientation is measured by X-ray diffraction in the middle of each detected grain.
Main technical Features
The sample surface is first illuminated by LED lamps located in a circle above the sample in two heights. Due to the different locations of the lamps, the sample is illuminated at different angles which optimizes the detection of grains. The grains are detected by a visual camera located above the sample.
The software is then calculating the middle of each grain where the grain orientiation is measured by the Laue method. A white X-ray beam creates a backscatter diffraction pattern of all possible lattice plane families, due to all wavelengths being included in the white X-ray beam. The measured Laue pattern is compared to known Laue pattern for the different grain orientations to detect the grain orientation in the measured spot.
Published by Rannveig Kvande , SINTEF