Measurement of strain distribution in multi-crystalline silicon substrates for solar cells using synchrotron radiation

In order to measure strain distribution in multi-crystalline silicon substrates, we have developed a synchrotron radiation white x-ray based Laue pattern mapping (LPM) method. The samples were a single-crystalline and a multi-crystalline silicon substrates. The experiments were carried out at the beamline BL28B2 at the SPring-8 third-generation synchrotron facility. In order to obtain local characteristics, the incident beam size was set to be 0.05mm square. The position of sample can be controlled by stepping motors and the sample was scanned two-dimensionally perpendicular to the direction of x-ray. The transparent Laue pattern was obtained by a x-ray imaging sensor at each measurement point. For comparison, x-ray topography (XRT) images were also measured. The results of LPM agreed with those of XRT images. It is indicated that the LPM is useful to measure strain distribution, especially for multi-crystalline silicon substrates.