"CRYSTAL-DIRECT" A Norway-Japan Bilateral Research Collaboration Project

CRYSTAL-DIRECT will establish a formal collaboration between SINTEF, NTNU, Hydro Solar and The Institute for Materials Research of Tohoku University in Japan. The goal of the experimental work is to investigate if it is possible to obtain laterally dendri tic growth in an early stage of directional solidification of multicrystalline silicon in a Bridgman furnace. Recent work at The Institute for Materials Research of Tohoku University has shown that silicon crystals nucleated at high undercooling will grow laterally in a dendritic way to single crystals, each covering large sections of the bottom of the solidification crucible. During subsequent slow directional solidification, these crystals will grow vertically with a planar front. This type of dendritic grain structure Si materials has been correlated to high conversion efficiency. The experiments at Tohoku University have all been done on a laboratory scale. In this project several growth conditions will be tested in order to reproduce the results obta ined in Japan in SINTEF/NTNU's pilot scale facilities. Results from the experiments will be shared by the project partners. By succeeding to control the grain size and orientation in multicrystalline silicon solidified in SINTEF/NTNU's pilot scale furnace , the project partners will write a joint proposal for developing this method further in the main project.