Grain control using spot cooling in multi-crystalline silicon crystal growth

High-quality multi-crystalline silicon (mc-Si) grown by directional solidification using notched crucibles

“…diameter by changing the crucible lowering speed. Using a similar concept, Wang et al [10] and Yeh et al [11] have applied spot cooling to control the supercooling locally, and with a good interface control [11], high-quality mc-Si crystals having high percentage of twins were grown. The area with twins showed a much lower dislocation density and higher minority carrier lifetime, and the solar cells fabricated from the material also show higher quantum efficiency [11].…”

Nucleation and bulk growth control for high efficiency silicon ingot casting

“…Nucleation may start from the edge of the crucible and grow inwards, or from the cooling spots and grow outwards. Fujiwara et al [3,4], Yeh et al [5], and Wang et al [6] performed extensive studies to improve the grain size, orientation, and stress during the initial stages of nucleation control. Unfortunately, most experiments were performed in small crystal growth systems.…”

An enhanced cooling design in directional solidification for high quality multi-crystalline solar silicon

“…Fujiwara et al [8] further adopted the idea for the growth of mc-Si ingots of 5-inch in diameter by changing the initial lowering speed of crucible. By using the similar concept, Wang et al [9] and Yeh et al [10] applied spot cooling to control the local nucleation, and indeed high-quality mc-Si crystals having high percentage of twins could be grown. The area with twins also showed much lower dislocation density and higher minority carrier lifetime.…”