1366 Technologies Inc.

General Electric Company

Motech Americas, LLC

Heritage Power LLC

Cubicpv Inc.

Ralf Jonczyk

Emanuel Michael Sachs

Richard Lee Wallace, Jr

Adam M Lorenz

G D Stephen Hudelson

James A Rand

Eerik Torm Hantsoo

Richard L Wallace

G D Hudelson

Brian Kernan

David S Harvey

Richard L Wallace, Jr

Stephen Pisklak

Scott L Kendall

Adam L Lorenz

Alysha Grenko

Gd Stephen Hudelson

Brian D Kernan

James Rand

A semiconductor wafer forms on a mold containing a dopant. The dopant dopes a melt region adjacent the mold. There, dopant concentration is higher than in the melt bulk. A wafer starts solidifying. Dopant diffuses poorly in solid semiconductor. After a wafer starts solidifying, dopant can not enter the melt. Afterwards, the concentration of dopant in the melt adjacent the wafer surface is less than what was present where the wafer began to form. New wafer regions grow from a melt region whose dopant concentration lessens over time. This establishes a dopant gradient in the wafer, with higher concentration adjacent the mold. The gradient can be tailored. A gradient gives rise to a field that can function as a drift or back surface field. Solar collectors can have open grid conductors and better optical reflectors on the back surface, made possible by the intrinsic back surface field.

Methods for creating a semiconductor wafer having profiled doping and wafers and solar cell components having a profiled field, such as drift and back surface

A main crucible of molten semiconductor is replenished from a supply crucible maintained such that there are always two phases of solid and liquid semiconductor within the supply crucible. Heat added to melt the solid material results in the solid material changing phase to liquid, but will not result in any significant elevation in temperature of the liquid within the supply crucible. The temperature excursions are advantageously small, being less than that which would cause problems with the formed product. The solid product material acts as a sort of temperature buffer, to maintain the supply liquid temperature automatically and passively at or very near to the phase transition temperature. For silicon, excursions are kept to less than 90&#xb0; C., and even as small as 50&#xb0; C. The methods also are useful with germanium. Prior art silicon methods that entirely melt the semiconductor experience excursions exceeding 100&#xb0; C.

Method for maintaining contained volume of molten material from which material is depleted and replenished

A semiconductor wafer forms on a mold containing a dopant. The dopant dopes a melt region adjacent the mold. There, dopant concentration is higher than in the melt bulk. A wafer starts solidifying. Dopant diffuses poorly in solid semiconductor. After a wafer starts solidifying, dopant cannot enter the melt. Afterwards, the concentration of dopant in the melt adjacent the wafer surface is less than what was present where the wafer began to form. New wafer regions grow from a melt region whose dopant concentration lessens over time. This establishes a dopant gradient in the wafer, with higher concentration adjacent the mold. The gradient can be tailored. A gradient gives rise to a field that can function as a drift or back surface field. Solar collectors can have open grid conductors and better optical reflectors on the back surface, made possible by the intrinsic back surface field.

Semi-conductor wafers with thin and thicker regions at controlled locations may be for Photovoltaics. The interior may be less than 180 microns or thinner, to 50 microns, with a thicker portion, at 180-250 microns. Thin wafers have higher efficiency. A thicker perimeter provides handling strength. Thicker stripes, landings and islands are for metallization coupling. Wafers may be made directly from a melt upon a template with regions of different heat extraction propensity arranged to correspond to locations of relative thicknesses. Interstitial oxygen is less than 6&#xd7;10atoms/cc, preferably less than 2&#xd7;10, total oxygen less than 8.75&#xd7;10atoms/cc, preferably less than 5.25&#xd7;10. Thicker regions form adjacent template regions having relatively higher heat extraction propensity; thinner regions adjacent regions with lesser extraction propensity. Thicker template regions have higher extraction propensity. Functional materials upon the template also have differing extraction propensities.

Methods and apparati for making thin semi-conductor wafers with locally controlled regions that are relatively thicker than other regions and such wafers

A pressure differential can be applied across a mold sheet and a semiconductor (e.g. silicon) wafer (e.g. for solar cell) is formed thereon. Relaxation of the pressure differential can allow release of the wafer. The mold sheet may be cooler than the melt. Heat is extracted through the thickness of the forming wafer. The temperature of the solidifying body is substantially uniform across its width, resulting in low stresses and dislocation density and higher crystallographic quality. The mold sheet can allow flow of gas through it. The melt can be introduced to the sheet by: full area contact with the top of a melt; traversing a partial area contact of melt with the mold sheet, whether horizontal or vertical, or in between; and by dipping the mold into a melt. The grain size can be controlled by many means.

Apparati for fabricating thin semiconductor bodies from molten material

An interposer sheet can be used for making semiconductor bodies, such as of silicon, such as for solar cell use. It is free-standing, very thin, flexible, porous and able to withstand the chemical and thermal environment of molten semiconductor without degradation. It is typically of a ceramic material, such as silica, silicon nitride, silicon oxynitride, silicon oxycarbide, silicon carbide, silicon carbonitride, silicon oxycarbonitride and others. It is provided between a forming surface of a mold sheet, and the molten material from which a semiconductor body will be formed. It may be secured to the forming surface or deposited upon the melt. The interposer sheet suppresses grain nucleation, and limits heat flow from the melt. It promotes separation of the semiconductor body from the forming surface. It can be fabricated before its use. Because free-standing and not adhered to the forming surface, problems of mismatch of CTE are minimized. The interposer sheet and semiconductor body are free to expand and contract relatively independently of the forming surface.

Making semiconductor bodies from molten material using a free-standing interposer sheet

A pressure differential is applied across a mold sheet and a semiconductor (e.g. silicon) wafer (e.g. for solar cell) is formed thereon. Relaxation of the pressure differential allows release of the wafer. The mold sheet may be cooler than the melt. Heat is extracted almost exclusively through the thickness of the forming wafer. The liquid and solid interface is substantially parallel to the mold sheet. The temperature of the solidifying body is substantially uniform across its width, resulting in low stresses and dislocation density and higher crystallographic quality. The mold sheet must allow flow of gas through it. The melt can be introduced to the sheet by: full area contact with the top of a melt; traversing a partial area contact of melt with the mold sheet, whether horizontal or vertical, or in between; and by dipping the mold into a melt. The grain size can be controlled by many means.

Selected methods for efficiently making thin semiconductor bodies from molten material for solar cells and the like

Methods and apparatus for fabricating a semiconductor sheet are provided. In one aspect, a method for fabricating a semiconductor wafer includes applying a layer of semiconductor material across a portion of a setter material, introducing the setter material and the semiconductor material to a predetermined thermal gradient to form a melt, wherein the thermal gradient includes a predetermined nucleation and growth region, and forming at least one local cold spot in the nucleation and growth region to facilitate inducing crystal nucleation at the at least one desired location.

Methods and apparatus for manufacturing semiconductor wafers

Methods for efficiently making thin semiconductor bodies from molten material for solar cells and the like

A method of making a release coating includes the following steps: forming a mixture that includes (a) solid components comprising (i) 20-99% silicon by weight and (ii) 1-80% silicon nitride by weight and (b) a solvent; applying the mixture to an inner portion of a crucible or graphite board adapted to form an ingot or wafer comprising silicon; and annealing the mixture in a nitrogen atmosphere at a temperature ranging from 1000 to 2000&#xb0; C. The invention may also relate to release coatings and methods of making a silicon ingot or wafer including the use of a release coating.

Silicon release coating, method of making same, and method of using same

Methods and systems for photovoltaic roofing systems are provided. The system includes a back sheet including a length, L, a width, W, and a thickness, T, the back sheet including an overlap portion extending along length L having a width, WO and an active portion extending along length L having a width, WA. The system also includes a photovoltaic cell formed on a surface of the active portion, the photovoltaic cell including a photovoltaic member electrically responsive to an absorption of photons, a negative electrode coupled to a surface of the photovoltaic member, and a positive electrode coupled to the surface of the photovoltaic member, wherein the thickness T is selected such that thickness T plus a thickness of the photoelectric cell substantially match a thickness of a proximate non-photovoltaic roofing member when the photovoltaic roofing system is installed.

Methods and systems for asphalt roof integrated photovoltaic modules

A material handling system for moving material from a storage device to a receiver comprises a counter rotating double screw feeder extending from the storage device to the receiver. The counter rotating double screw feeder comprises an outer screw feed member; an inner screw feed member; where the outer screw feed member being positioned in an outer screw feed member tube; and the inner screw feed member being positioned in an inner screw feed member tube. The material is feed from the storage device to the process tube via the outer screw feed member; the inner screw feed member removes gas and byproducts from the receiver.

Material handling system and method

There is provided a method of fabricating a wafer, comprising depositing semiconductor material into a recess in a setter, moving the setter through a heating/cooling region to subject the semiconductor material to a temperature profile, and removing a wafer from the recess. The size and shape of the wafer are substantially equal to the size of the wafer when it is used. As a result, the wafer can be fabricated in any desired shape and with any of a variety of surface structural features and/or internal structural features. The temperature profile can be closely controlled, enabling production of wafers having structural features not previously obtainable. There are also provided wafers formed by such methods and setters for use in such methods.

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Concord, MA, United States of America

Ralf Jonczyk