Abstract: An apparatus for purifying metallurgical grade silicon to produce solar grade silicon has a container for holding molten silicon and one or more torches for providing oxygen and hydrogen gas to heat the molten silicon so that the reaction time is prolonged, to create turbulence, and to introduce silica powder and water vapor for reactions with molten silicon. The molten silicon is then directionally solidified.

Abstract: An apparatus for purifying metallurgical grade silicon to produce solar grade silicon has a container for holding molten silicon and one or more submergible torches for providing a flame surrounded by inert gas to heat the molten silicon so that the reaction time is prolonged, to create turbulence, and to introduce silica powder and water vapor for reactions with molten silicon. The molten silicon is then directionally solidified by providing the container in a coolant tank and controlling the coolant level with controllable valves so that further purification is achieved by segregating impurities.

Abstract: A cutting blade the core of which is generally tear-drop shaped in cross-section. The sides of the tear-drop shaped core form an included angle of not less than about 5 degrees (and typically not less than about 9 degrees), and abrasive is provided essentially on only the wide bottom surface of the core.

Abstract: A high temperature heat exchanger is used with the Czochralski crystal growing method to control the heat extraction from crystal silicon ingots as they are grown. The high temperature heat exchanger also acts as a shaping die so that silicon bars, or ingots, of various shapes, including square, circular, rectangular or ribbon, can be produced by shaping during the growth stage.

Abstract: A process that, without doping of PBN crucibles, produces semi-insulating GaAs having low, or essentially no, dislocation density; and in which the crystal may be in situ annealed after growth. The process is a variant of the Heat Exchanger Method (HEM) disclosed in U.S. Pat. No. 3,898,051. Crack-free, semi-insulating GaAs crystals having low dislocation density are grown from presynthesized undoped GaAs meltstock in sealed quartz (vitreous silica) crucibles, without the need for an encapsulant. One aspect of the invention features seeded growth of <100> orientation crystals having a dislocation density 1-2 orders of magnitude less than that of the seed; in another aspect, crystals having fewer than 500 dislocations/cam.sup.2 in their center column are grown without a seed.

Abstract: A wafering machine having a multiplicity of wire cutting blades supported by a bladehead reciprocally moving past a workpiece supported by a holder that rocks about an axis perpendicular to the wires at a frequency less than the reciprocation of the bladehead.

Abstract: A wafering machine having a multiplicity of wire cutting blades supported by a bladehead reciprocally moving past a workpiece supported by a holder that rocks about an axis perpendicular to the wires at a frequency less than the reciprocation of the bladehead.

Abstract: A narrow wire blade with abrasive particles plated within a longitudinally-extending, plated cutting portion that extends from only one side of a wire core and has parallel side walls spaced by a controlled width.

Abstract: In the growing of crystals, the formation of carbide contaminants is prevented by eliminating direct silica-graphite contact.

Abstract: Ingots are cast in silica containers in which the interior surface of the container is defined by a thin skin of high density glass behind which the silica wall varies in density and cristobalite phase content.