Modification of local structures in multicrystals revealed by spatially resolved x-ray rocking curve analysis

We show that spatially resolved x-ray rocking curve analysis can be a useful technique to investigate local structures in bulk multicrystals and their modification during crystal growth when combined with appropriate samples. For this purpose, a model crystal growth experiment was carried out using a Si seed crystal with artificially controlled 〈 110 〉 tilted grain boundaries. The growth orientation was chosen as the scan axis for rocking curve measurements in different crystal grains. Thanks to the superior angle resolution, the gradual structural changes can be monitored by the changes in the rocking curve profile such as the peak shift and the peak splitting. The amount as well as the sign of the peak shift was found to be strongly dependent on the initial grain boundary structure. Furthermore, the technique was applied to investigate local structures of Si multicrystals with controlled grain orientation grown without any seeds.