Patent ID: 8721789
Filing Date: 2014-05-13
Classification: B22D,C03B,C30B,F27B,F27D,Y10T

Abstract:
1. An apparatus for crystallization of silicon comprising: a crucible for containing silicon; a heating and heat dissipating arrangement provided for melting the silicon contained in the crucible and for subsequently solidifying the molten silicon; an electromagnetic stirring device provided for stirring the molten silicon in the crucible and causing the molten silicon to circulate within the crucible during the solidification of the molten silicon, a control arrangement comprising one or more microcomputers, said control arrangement operatively connected to the heat and heat dissipating arrangement and to the electromagnetic stirring device, and software executing on the one or more microcomputers, said one or more microcomputers being configured to receive input data, said software being configured to control the electromagnetic stirring device to stir the molten silicon in two stages such that a first speed of the molten silicon circulating within the crucible is obtained in a first stage of the two stages and a second speed of the molten silicon circulating within the crucible is obtained in a second stage of the two stages, the first speed of the molten silicon circulating within the crucible being higher than the second speed of the molten silicon circulating within the crucible, said software being configured to control the heating and heat dissipating arrangement to solidify the molten silicon at a specified solidification rate, said software being further configured to control the electromagnetic stirring device to stir the molten silicon at a speed in response to the specified solidification rate of the molten silicon such that the ratio of the speed of the molten silicon circulating within the crucible and the specified solidification rate is above a first threshold value, wherein the first threshold value is at least 10.