Device for producing polycrystalline silicon

Claim 1

A device for producing polycrystalline silicon by purifying silicon which contains impurities and solidifying a liquid molten mass of purified silicon by subjecting the liquid mass to a vertical temperature gradient, said device comprising: a chamber, a first crucible within said chamber for containing a mixture of carbon and silica, means for heating said first crucible, and means for tilting said crucible about a horizontal axle, a second crucible positioned within said chamber below said first crucible and positioned to receive the liquid bath of molten silicon which contains impurities upon tilting of said first crucible about said horizontal axle, said second crucible having a drainage orifice within a lower part thereof, movable means for stopping said drainage orifice, a pipe passing through the wall of said chamber and leading to the inside of said second crucible, means for connecting said pipe to a source of gas for bubbling through the molten silicon, means for heating said second crucible to maintain the temperature of said bath above the melting point of silicon, a vertical receptacle disposed beneath said second crucible and positioned relative to said orifice so as to receive the purified liquid silicon flowing from said orifice when said orifice is not stopped, a heating sleeve surrounding said receptacle and means for maintaining the temperatures at the top and bottom of said sleeve respectively higher and lower than the melting point of silicon, means for vertically moving said receptacle along the axis of said sleeve, and pumping means for pumping the gases out of said chamber.

Claim 2

A device for producing polycrystalline silicon by purifying silicon which contains impurities and solidifying a liquid molten mass of purified silicon by subjecting the liquid mass to a vertical temperature gradient, said device comprising: a chamber, a first crucible within said chamber for containing a mixture of carbon and silica, means for heating said first crucible, and means for tilting said crucible about a horizontal axle, a second crucible positioned within said chamber below said first crucible and positioned to receive the liquid bath of molten silicon which contains impurities upon tilting of said first crucible about said horizontal axle, said second crucible having a drainage orifice within a lower part thereof, movable means for stopping said drainage orifice, a pipe passing through the wall of said chamber and leading to the inside of said second crucible, means for connecting said pipe to a source of gas for bubbling through the molten silicon, means for heating said second crucible to maintain the temperature of said bath above the melting point of silicon, a vertical receptacle disposed beneath said second crucible and positioned relative to said orifice so as to receive the purified liquid silicon flowing from said orifice when said orifice is not stopped, a heating sleeve surrounding said receptacle and means for maintaining the temperatures at the top and bottom of said sleeve respectively higher and lower than the melting point of silicon, means for vertically moving said receptacle along the axis of said sleeve, and pumping means for pumping the gases out of said chamber.