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Advanced Crystal Products Corporation

David N Jewett

Joseph B Milstein

Herbert E Bates

Brian H Mackintosh

A method and system for growing elongated crystalline materials. Crystalline melt rises through a capillary. At the upper end of the capillary is a die having a die tip. A seed crystal engages and draws the melt through the die tip. The die tip is characterized by a top surface and an aperture therein. The top surface is non-wetting with reference to the crystalline melt. The geometry of the aperture or inner edge defines the geometry of the crystalline filament formed.

Inside edge defined, self-filling (IESF) die for crystal growth

A system and process for growing extremely high quality single crystal materials, particularly silicon and other semiconductor materials, containing a generally uniform distribution of dopants, impurities, and oxygen, both axially and radially, wherein the concentration of impurities and oxygen and the number of defects are minimized. A significant feature is the use of a shallow tray-like crucible consisting of a replenishment zone and at least one crystal growth zone independently heated by one or more heating elements through the bottom of the crucible. In the preferred embodiment, an oval shaped crucible is used which consists of one replenishment zone and one growth zone. In one embodiment, a spiral shaped heater is centered underneath the feed rod and growing crystal and a 'picture frame' shaped heater is located underneath the outer edges of the replenishment and growth zones to provide a more controlled thermal gradient. Mechanical pumping produces a controlled, directed, three-dimensional flow within the melt from the replenishment zone to the growth zone. The pumping is achieved either by rotation of a solid feed rod in the replenishment zone or by a strong directed flow of an inert gas onto the surface of the melt. Guide elements positioned within the crucible assist in directing the pumped flow from the replenishment zone to the growth zone so that the flow sweeps through the growth zone under the crystal to produce a thin boundary layer at the growing crystal surface, uniformly mixes in the dopant, and removes any impurity build up in the growth zone. Optionally, magnets to increase apparent melt viscosity and improve flow control and separate dopant addition mechanisms may be utilized.

System for growth of single crystal materials with extreme uniformity in

In a low angle silicon sheet growth process, a puller mechanism advances a seed crystal and solidified ribbon from a cooled growth zone in a melt at a low angle with respect to the horizontal. The ribbon is supported on a ramp adjacent the puller mechanism. Variations in the vertical position of the ribbon with respect to the ramp are isolated from the growth end of the ribbon by (1) growing the ribbon so that it is extremely thin, preferably less than 0.7 mm, (2) maintaining a large growth zone, preferably one whose length is at least 5.0 cm, and (3) spacing the ramp from the growth zone by at least 15 cm.

Guidance system for low angle silicon ribbon growth

A method and associated apparatus are disclosed for use in forming crystalline ribbons by pulling a ribbon in a generally horizontal direction from a pool of molten crystal-forming materials, such as silicon or the like. A heat sink is located above the surface of the molten material proximate to the crystal forming area to remove heat therefrom. The heat sink is cooled continuously and heat is transferred from the molten material to the heat sink by a gaseous thermally conductive medium maintained between the heat sink and the surface of the melt.

Controlled heat sink for crystal ribbon growth

A method and associated apparatus are disclosed for the continuous formation of single crystal silicon ribbons. A seed crystal is placed on the surface of a pool of molten silicon and pulled at a slight angle above the horizontal over the edge of a meniscus attachment member at a rate commensurate with the rate of growth of the ribbon. The formation of the ribbon is controlled in part by a submerged stabilizer disposed under the molten silicon below the advancing edge of the ribbon at the surface of the silicon. A thermal impedance is provided below the surface of the molten silicon to provide stability in the formation of the ribbon and to provide the proper temperature gradients conducive to the efficient formation of the ribbon from the molten material.

Method and apparatus for producing crystalline ribbons

A method and related apparatus are provided for producing on a semi-continuous basis polycrystalline silicon and melt replenishment for a crystal growth crucible. The silicon is deposited in low density form on the inner walls of a multi-walled reaction chamber by delivering gaseous HSiCL.sub.3, SiH.sub.4, or the like, and reducing gas if needed, through the chamber which is heated to the reaction temperature of the feed gas. After a certain amount of silicon has been produced, the chamber temperature is raised sufficiently to melt down the silicon which is then used to replenish a crystal growth crucible. The operations are then cyclically repeated. The apparatus includes a reaction chamber having a multi-walled configuration to maximize the interior surface area on which the silicon is deposited. A drain trap such as a U-shaped tube, or the like, is connected to the bottom of the reaction chamber and provided with heating elements. Silicon collected on the walls of the reaction chamber, when periodically melted, flows through the drain trap and a delivery tube to a crystal growth system. By selectively adjusting the temperature in the trap, either above or below the melting point of the silicon, the silicon is alternately liquified or solidified so that the liquid/solid transition of the silicon in the trap acts as a valve between the reaction chamber and the crystal growth system.

Apparatus for producing semiconductor grade silicon and replenishing the

A temperature profile controller is provided for cooling a crystal as it is pulled from a melt so that a substantially linear temperature gradient is established and maintained along the length of the crystal as it is cooled, whereby to prevent or reduce the occurrence of residual stresses in the crystal.

Method for reducing residual stresses in crystals

Method and apparatus for reducing residual stresses in crystals

A new method and apparatus for producing silicon are disclosed which are characterized by using a silicon tube as the reaction chamber and disproportionating a gaseous silicon compound so as to produce silicon and deposit the same on the inner surface of the reaction chamber.

Manufacture of silicon on the inside of a tube

A novel cartridge containing selected crystal growth components is provided for use in a crystal growing system. The cartridge is adapted to be mounted directly to a crystal pulling mechanism and is arranged so that it can be inserted into a furnace containing a supply of molten feed material. The cartridge includes a crystal growing die, a die holder, and associated crystal growth components arranged to permit rapid growth of selected shape. The cartridge is assembled outside of the furnace at room temperature and can be inserted into and removed from the furnace without having to cool the latter.

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Harvard, MA, United States of America

David N Jewett