Growth of multicrystalline silicon ingot from the top of the melt: Control of microstructures and reduction of stress

We attempted to grow high-quality multicrystalline Si ingot based on solidification of Si melt from the top to the bottom in a crucible. Growth from the top of the melt permits to directly observe the initial stage of the crystal growth and control microstructures by utilizing dendrite crystals. Specially designed double crucibles were utilized to reduce introduction of the stress to the ingot especially at the final stage of the solidification so that generation of dislocations can be suppressed. The growth method was successfully implemented to fabricate multicrystalline Si ingot for practical size wafers.