Atlantic Richfield Company

Solaicx, Inc.

David L Bender

G Felix Wakefield

Samuel N Rea

David E A Smith

Gary Janik

Kim W Mitchell

Roy P Crawford

A method is disclosed for continuous CZ crystal growing wherein one or more crystal ingots are pulled into a growth chamber from a crystal/melt interface defined in a crucible containing molten crystalline material that is continuously replenished by crystalline feedstock. The method includes separating the molten crystalline material, controlling the flow of the molten crystalline material and defining an annular space with respect to sidewalls of a heat shield in the chamber.

Weir method for improved single crystal growth in a continuous Czochralski process

An improved system based on the Czochralski process for continuous growth of a single crystal ingot comprises a low aspect ratio, large diameter, and substantially flat crucible, including an optional weir surrounding the crystal. The low aspect ratio crucible substantially eliminates convection currents and reduces oxygen content in a finished single crystal silicon ingot. A separate level controlled silicon pre-melting chamber provides a continuous source of molten silicon to the growth crucible advantageously eliminating the need for vertical travel and a crucible raising system during the crystal pulling process. A plurality of heaters beneath the crucible establish corresponding thermal zones across the melt. Thermal output of the heaters is individually controlled for providing an optimal thermal distribution across the melt and at the crystal/melt interface for improved crystal growth. Multiple crystal pulling chambers are provided for continuous processing and high throughput.

System for continuous growing of monocrystalline silicon

A weir is extended vertically to define an optimal annular gap between the top of the weir and the underside of a super-adjacent heat shield. The annular gap provides a high velocity stream of argon gas to be directed from the growth region to the melt region to substantially eliminate the transport of airborne particles from the melt region to the growth region. The tall weir may be configured as a modular, reusable weir extension supportably engaged with an outer (and/or inner) weir.

Weir design providing optimal purge gas flow, melt control, and temperature stabilization for improved single crystal growth in a continuous Czochralski process

A weighing system is provided for a continuous Czochralski process that accurately measures the weight of the crucible and melt during crystal growth to control the introduction of feedstock in order to keep the weight approximately constant. The system can measure the weight of the crucible while the crucible is rotating, and is insensitive to vibrations of the melt surface as well as variable torques on the crucible shaft induced by the rotation. The system also measures the weight of the crucible and its contents in order to control the amount of feedstock recharged after an ingot is withdrawn.

Crucible weight measurement system for controlling feedstock introduction in Czochralski crystal growth

A wire saw and wafer stabilizing system are provided for holding wafer sections invariantly against vibration and unwanted movement during the sawing process. A stabilizing means is applied to the ends of partially defined wafer sections at an early stage when the wafer sections are partially cut through a silicon ingot or block of silicon material. The stabilizing means serves to stabilize the wafer sections immovably against vibration, oscillation, or unwanted contact during the subsequent sawing process. The stabilizing system also accelerates handling of the wafers after slicing is completed, facilitates the cleaning process, and allows for more rapid or automated placement of the wafers in cassettes. Wafers produced by the stabilizing system are characterized by a minimized total thickness variation, substantially uniform planarity, and substantially without bow or warp.

Method and apparatus for cutting ultra thin silicon wafers

Apparatus for production of semiconductor ribbon materials of the type in which molten material is brought into contact with the surface of a rotating cool wheel or drum wherein the cooling surface of the drum is textured to form a plurality of discrete contacting points to enhance growth of large crystal grains.

Textured silicon ribbon growth wheel

An electrically enhanced liquid jet process particularly adapted for forming scribe lines on thin film material deposited during fabrication of thin film solar cell devices. A narrow jet of liquid solution is directed onto a thin film along a desired line while an electrical current is passed through the liquid jet and the film being processed. The liquid solution is selected to remove material along the desired line only at its point of contact with the film but to be substantially nonreactive with the film in all other areas where there is an absence of electrical enhancement.

Electrically enhanced liquid jet processing

A tundish for use in casting a ribbon of crystalline or coarse grain polycrystalline material, having a support for a hopper containing molten material, the hopper having a bottom plate and three side wall plates and a top plate, each made of a material which will not interact with the molten material contained within the space defined by the bottom plate, side wall plates and top plate, to impart any significant impurity into the molten material, and wherein the top plate slants downwardly towards the bottom plate to form an elongated orifice through which molten material is extruded onto a cool surface where crystallization of a ribbon of material occurs. As disclosed, the top plate is movable with respect to the bottom plate to change the thickness of the orifice. Also as disclosed, the top plate slides in a slot in each of two opposed side walls and is of a length such that it forms with the third side wall an opening into which molten material is added to the tundish.

Tundish for ribbon casting of semiconductor ribbon

Apparatus and method for producing semiconductor ribbon directly from the molten state by contact with a moving chill surface wherein water vapor is introduced to improve ribbon top surface smoothness.

Surface improvement of semiconductors in high speed casting

Apparatus and method for producing semiconductor ribbon directly from the molten state by contact with a moving chill surface wherein the chill surface has longitudinal grooves near its outer edges to define ribbon width and improve smoothness of ribbon edges.

Silicon ribbon growth wheel with edge defining grooves

A silicon ribbon growth wheel having a thermal resistance zone between an outer silicon contacting surface and an inner cooling fluid contacting surface to control rate of heat flow from the outer to inner surfaces. In a preferred form the thermal resistance zone is defined by a row of holes through the wheel near the outer surface with said holes isolated from the cooling fluid. A method for controlling the heat flow is also diclosed.

Silicon ribbon growth wheel and method for heat flow control therein

A silicon ribbon growth wheel having an internal cooling fluid contacting surface modified to provide a lateral temperature profile on the wheel surface of lower temperature near the wheel edges. In a preferred form the inner surface is provided with grooves near the wheel edges to increase heat conduction to the cooling fluid at the wheel edges. A method for surface temperature profiling the growth wheel is also disclosed. A method for surface temperature profiling the growth wheel is also disclosed.

Silicon ribbon growth wheel and method for surface temperature profiling

A take-up reel and take-up reel starting feed for use in high speed ribbon crystallization of molten material e.g., a metal or a semiconductor material, in which a starting strip is pre-wound onto the take-up reel sufficiently to frictionally engage the take-up reel and be thereby drawn onto the take-up reel from a supply reel for the starting strip, and wherein the linear velocity of the starting strip in a contact zone is synchronized with the linear velocity of a cast ribbon of the material leaving a rotating drum on which the casting initiated, so that the ribbon of cast material, after it passes over the starting strip in the contact zone, will contact the starting strip and pass onto the take-up reel in contact with the starting strip and without bunching or significant stretching of the ribbon of cast material. After a sufficient number of revolutions of the take-up reel to ensure that the ribbon of cast material is frictionally engaged by the wrapping of a sufficient amount of the ribbon and starting strip, in contact with each other, about the take-up reel, the starting strip may be severed, leaving only the ribbon of cast material in the remaining wraps on the take-up reel.

Growing community of inventors

Thousand Oaks, CA, United States of America

David L Bender