Title of Invention	"PROCESS FOR DEPOSITING A VAPORIZED CHEMICAL MATERIAL ON A SUBSTRATE"
Abstract	The present invention relates to a process for coating a substrate heated to a temperature below the condensation temperature of a semiconductor material at atmospheric pressure, comprising the steps of mixing a controlled mass of semiconductor material and a heated inert gas stream; vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature above the condensation temperature of the semiconductor material; directing the fluid mixture at the substrate, wherein the substrate is at atmospheric pressure; and depositing a layer of the semiconductor material onto a surface of the substrate.

Title of Invention

"PROCESS FOR DEPOSITING A VAPORIZED CHEMICAL MATERIAL ON A SUBSTRATE"

Abstract

The present invention relates to a process for coating a substrate heated to a temperature below the condensation temperature of a semiconductor material at atmospheric pressure, comprising the steps of mixing a controlled mass of semiconductor material and a heated inert gas stream; vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature above the condensation temperature of the semiconductor material; directing the fluid mixture at the substrate, wherein the substrate is at atmospheric pressure; and depositing a layer of the semiconductor material onto a surface of the substrate.

Full Text	ATMOSPHERIC PRESSURE CHEMICAL VAPOR DEPOSITION CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of provisional patent application Serial No. 60/602,405, filed August 18, 2004. FIELD OF THE INVENTION [0002] The present invention relates generally to the deposition of a vaporized chemical material on a substrate, and more particularly to a process for depositing a vaporized chemical material on a substrate at atmospheric pressure. BACKGROUND OF THE INVENTION [0003] Chemical vapor deposition processes such as pyrolytic processes and hydrolytic processes are well known in art of coating substrates. The physical characteristics of the coating reactants utilized in such processes may be liquid, vapor, liquids or solids dispersed in gaseous mixtures, aerosols, or vaporized or vaporous coating reactants dispersed in gaseous mixtures. [0004] In the process of deposition of a vaporized chemical compound on a glass substrate in the production of photovoltaic devices, the vaporized chemical compound is typically deposited in a vacuum atmosphere. The systems for carrying out such process have typically included a housing having an enclosed deposition chamber formed of a lower portion and an upper portion with a horizontal junction with each other. A seal assembly is interposed at the junction between the lower and upper housings. A conveyor means is provided to transport glass sheet substrates through the chamber. A chemical vapor distributor is located within the deposition chamber to provide a coating on the glass substrate as the substrate passes through the chamber. [0005] The system includes a vacuum source for drawing a vacuum within the deposition chamber. The deposition chamber typically includes elongate heaters for heating the glass sheets as they are conveyed through the system. The glass sheets pass into the deposition chamber from a vacuum-heating furnace to the vacuum deposition chamber that is maintained at a similar vacuum and temperature setting as the heating furnace. Powdered cadmium sulfide and powdered cadmium telluride are fed into the vaporization deposition chamber. The films are then deposited onto the previously coated and heated glass substrates sequentially. The coated substrates are next transferred through a load lock and thence into a cooling chamber wherein cooling is effected by compressed nitrogen and finally conveyed to atmosphere pressure though an exit load lock to an air cooling section for reduction to ambient temperature. The cadmium telluride thinfilm material requires a follow-on processing step to re-crystallize its polycrystalline structure so that effective photovoltaic devices can be made from the film stack. Typically this step is accomplished by applying a solution of cadmium chloride to the cadmium telluride surface of the cooled coated glass and re-heating the glass to a temperature of about 390°C to 420°C for a period of about 15 to 20 minutes. Care must be taken to slowly heat and cool the glass to avoid breakage during this treatment which extends the overall process time of the required step. [0006] Since it is well recognized that renewable energy sources are becoming increasingly more important, it is deemed that commercial production of photovoltaic devices for the generation of electrical energy is important in satisfying the renewable energy needs. The utilization of thin-film coatings of semiconductor materials on glass substrates is considered to be a viable mechanism in the field of photovoltaic-based electrical energy generation systems. [0007] It has been found that thin-film coating systems, based upon the above referred to technology, are capable of depositing thin film of cadmium sulfide/cadmium telluride photovoltaic material onto commercially available sodalime glass substrates in a vacuum. The photovoltaic materials are subsequently treated to re-crystallize the cadmium telluride surface making the film stack ready for further processing into photovoltaic devices. While the above-described system is capable of producing photovoltaic panels suitable for the production of electrical energy, it would be desirable to reduce the cost for such production to render the system commercially viable. SUMMARY OF THE INVENTION [0008] It is an object of the present invention to produce a photovoltaic panel by depositing thin-films of semiconductor materials from chemical vapors on a substrate at atmospheric pressure. [0009] Another object of the present invention is to produce a photovoltaic panel by vaporizing cadmium sulfide and cadmium telluride and depositing the same on the surface of a heated substrate to form a first thin film of cadmium sulfide and a second thin film of cadmium telluride at atmospheric pressure. [0010] Another object of the present invention is to produce a photovoltaic panel by rapid high temperature re-crystallization of the thin-film cadmium telluride polycrystalline material to yield high efficiency photovoltaic devices. [0011] It has surprisingly been found that the above objects may be achieved by a process for coating a substrate at atmospheric pressure, comprising the steps of: (1) providing sources of semiconductor materials such as cadmium sulfide or cadmium telluride; (2) heating and vaporizing the semiconductor materials at substantially atmospheric pressure, and maintaining the vaporized materials at temperatures above their temperatures of condensation; and (3) sequentially depositing the vaporized materials on a heated surface of a substrate such as glass at substantially atmospheric pressure, to form a laminar structure, Optionally, while the laminar structure is still substantially at the temperature of deposition and at substantially atmospheric pressure, a cadmium telluride layer may be treated with a reactive gas to effect a re-crystallization of the cadmium telluride. Subsequent processing of the laminar film stack may be accomplished to produce active thin-film photovoltaic devices. BRIEF DESCRIPTION OF THE DRAWING [0012] The above as well as other objects and advantages of the invention will become readily apparent to those skilled in the art from reading the following - 3 - detailed description of a preferred embodiment of the invention in the light of the accompanying drawing, in which: [0013] The drawing shows in schematic form the inventive steps of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0014] Referring to the drawing, there is schematically illustrated the steps of the process for coating a surface of a substrate with a film of cadmium telluride at atmospheric pressure. [0015] Individually metered masses of semiconductor material, preferably cadmium sulfide (CdS) or cadmium telluride (CdTe) in powdered form, are introduced into a zone which is continuously purged by a stream of inert gas, preferably nitrogen, flowing between an inlet and an outlet at approximately atmospheric pressure. The powder is carried from the inlet, by the inert gas flowing at a controlled rate, into a vaporizer consisting of a heated packed bed in which the powder is vaporized as it passes through the interstitial voids of the packed bed's media. The outlet of the heated packed bed is caused to communicate with the interior of a heated zone to distribute the vaporized material to the substrate. Alternative powder vaporization methods through which the metered powder mass and carrier inert gas are heated may be employed for generating the vaporized material fluid stream. The alternative methods may include, but are not necessarily limited to, heated fluidized beds in which the carrier inert gas is heated and the powder is vaporized, thermal "flash" vaporizers that heat the carrier inert gas and vaporize the powder, and atmospheric pressure thermal spray units that heat the carrier inert gas and vaporize the powder. [0016] The fluid, preferably including cadmium sulfide or cadmium telluride powder and the carrier inert gas, is a high temperature flowing mixture comprising the carrier inert gas and vaporized material at a temperature above its condensation temperature. The temperature of the fluid mixture is typically in a range of from about 800°C to about 1,100°C. The heated fluid mixture is then directed into an apparatus for producing a laminar flow of constant velocity toward the surface of a substrate at substantially atmospheric pressure. The substrate is typically a soda- lime glass, preferably having a low-E coating that is transparent and electrically conductive. An example of such glass is produced by Pilkington Glass Co. and is designated as TEC-15. The surface of the substrate is maintained at a temperature of from about 585°C to about 650°C. [0017] The apparatus for producing the desired laminar flow of fluid mixture comprises of a series of individual passageways adapted to cause a series of velocity changes in the transient fluid as the fluid flows through the passageways. The apparatus is maintained above the vaporization temperature of the cadmium sulfide or cadmium telluride, to prevent condensation of the material within the passageways. Such fluid flow evenly distributes the fluid mixture to an elongate outlet nozzle, and enables uniform laminar flow at constant mass flow distribution to flow tangentially of and supplied to the surface of the substrate. The above action causes the molecules of the fluid mixture to be evenly distributed throughout the length of the elongate outlet nozzle, and causes the molecules to travel from the outlet nozzle in a generally parallel path and at a constant velocity, producing a laminar flow of constant velocity and mass distribution directed toward the substrate. [0018] The velocity of the fluid mixture exiting the outlet nozzle may be regulated by controlling the mass flow rate at which the fluid mixture is introduced at the inlet. [0019] In order to control the thin-film deposition rate of the vaporized material within the fluid emitted from the apparatus being applied to the substrate, the mass flow rate of the fluid mixture and the velocity of the substrate are controlled while controlling the temperature of the substrate below the vaporized material's condensation point. As the heated fluid mixture impinges onto the cooler substrate, it cools to a temperature below the condensation temperature of the vaporized material. The material condenses from the fluid mixture, in a polycrystalline form, onto the moving substrate as a continuous thin-film layer. A fluid extraction device is disposed upstream and downstream of the outlet nozzle, to enable the controlled withdrawal of the non-film generating constituents of the fluid mixture directed to the surfaces of the substrate. [0020] While there may be a number of different systems for evenly distributing the vaporized cadmium sulfide or cadmium telluride on the surface of the transient glass substrate, it is contemplated that the apparatus illustrated and described in U.S. Patent 4,509,526 to Hofer et al. may provide satisfactory results. [0021 ] The deposition of any number of consecutive layers of cadmium sulfide and/or cadmium telluride by the apparatus described above, to prepare a laminar structure, is contemplated by the present invention. [0022] Subsequent to the deposition of a cadmium telluride polycrystalline thin-film, a re-crystallization step would be required to allow the production of photovoltaic devices from the laminar thin-film stack. It has been found that this step can be achieved in less than one minute by subjecting the hot cadmium telluride film to a hot gaseous atmosphere of dilute hydrogen chloride in nitrogen at substantially one atmosphere of pressure. The ability to control the recrystallization of the cadmium telluride while maintaining the temperature of the substrate eliminates cool-down and re-heating of the substrate/fihn-stack assembly during the re-crystallization step. The use of a "dry" re-crystallization step eliminates the use of a toxic cadmium chloride solution and its application apparatus. Typically, a glass substrate exiting the in-line re-crystallization process would have a temperature from about 620°C to about 630°C. This temperature range allows the glass to be thermally tempered by cool quenching gas flows as the substrate/film-stack exits the processing line. [0023] The above-described process relates to a method for producing a thinfilm cadmium sulfide/cadmium telluride photovoltaic material on the surface of a soda-lime glass substrate, to provide large area photovoltaic panels. However, it must be understood that the concept of atmospheric vapor deposition can be extended to include other thin-film materials that are normally deposited in a vacuum. [0024] Thin-film photovoltaic materials that could be considered are CIGS (copper-indium-gallium-diselenide), CdS/CIS-alloy (cadmium sulfide/copperindium- selenium alloy), amorphous silicon or thin-film polycrystalline silicon, and Zn (O, S, OH)X/CIGS (zinc oxide sulfide hydroxide/copper-indium-galliumdiselenide). [0025] Other thin-film materials that can be considered for application to glass substrates are optical coatings such as multi-layer stacks used for very low emissivity films and anti-reflection films. Other value added features such as improved durability films, self-cleaning films, photo-optic, and electro-optic films could be developed using the inventive atmospheric pressure deposition concept. [0026] The process of atmospheric pressure deposition of thin-film materials could be applied to a variety of substrate materials for enhancement of their surface properties. Substrates that could be considered include polymeric materials, ceramics, metals, wood, and others. We Claim: 1. A process for coating a substrate heated to a temperature below the condensation temperature of a semiconductor material at atmospheric pressure, comprising the steps of: mixing a controlled mass of semiconductor material and a heated inert gas stream; vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature above the condensation temperature of the semiconductor material; directing the fluid mixture at the substrate, wherein the substrate is at atmospheric pressure; and depositing a layer of the semiconductor material onto a surface of the substrate. 2. The process as claimed in claim 1, wherein the semiconductor material is one of cadmium sulfide and cadmium telluride. 3. The process as claimed in claim 1, wherein the inert gas is nitrogen. 4. The process as claimed in claim 1, wherein the temperature of the fluid mixture ranges from 800 degrees C to 1,100 degrees C. 5. The process as claimed in claim 1, wherein the substrate comprises glass. 6. The process as claimed in claim 5, wherein the glass includes a transparent, electrically conductive coating. 7. The process as claimed in claim 1, wherein the substrate has a temperature ranging from 585 degrees C to 650 degrees C. 8. The process as claimed in claim 1, wherein the steps of vaporizing, directing, and depositing are repeated at least once, to deposit at least one additional layer of semiconductor material on the substrate. 9. A process for coating a substrate heated to a temperature below the condensation temperature of a semiconductor material at atmospheric pressure, comprising the steps of: mixing a controlled mass of semiconductor material and a heated inert gas stream; vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature ranging from 800 degrees C to 1,100 degrees C; directing the fluid mixture at the substrate having a transparent, electrically conductive coating and having a temperature range from 585 degrees C to 650 degrees C and at atmospheric pressure; and depositing a layer of the semiconductor material onto a surface of the substrate. 10. The process as claimed in claim 9, wherein the steps of vaporizing, directing, and depositing are repeated at least once, to deposit at least one additional layer of semiconductor material on the substrate. 11. A process for coating a substrate heated to a temperature below the condensation temperature of a semiconductor material at atmospheric pressure, comprising the steps of: mixing a controlled mass of semiconductor material and a heated inert gas stream; vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature ranging from 800 degrees C to 1,100 degrees C; directing the fluid mixture at the substrate having a transparent, electrically conductive coating and having a temperature range from 585 degrees C to 650 degrees C and at atmospheric pressure; depositing a layer of the semiconductor material onto a surface of the substrate; and repeating the steps of vaporizing, directing, and depositing at least once, to deposit at least one additional layer of semiconductor material onto the substrate.

Full Text

ATMOSPHERIC PRESSURE CHEMICAL VAPOR DEPOSITION
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of provisional patent application
Serial No. 60/602,405, filed August 18, 2004.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the deposition of a vaporized
chemical material on a substrate, and more particularly to a process for depositing
a vaporized chemical material on a substrate at atmospheric pressure.
BACKGROUND OF THE INVENTION
[0003] Chemical vapor deposition processes such as pyrolytic processes and
hydrolytic processes are well known in art of coating substrates. The physical
characteristics of the coating reactants utilized in such processes may be liquid,
vapor, liquids or solids dispersed in gaseous mixtures, aerosols, or vaporized or
vaporous coating reactants dispersed in gaseous mixtures.
[0004] In the process of deposition of a vaporized chemical compound on a
glass substrate in the production of photovoltaic devices, the vaporized chemical
compound is typically deposited in a vacuum atmosphere. The systems for
carrying out such process have typically included a housing having an enclosed
deposition chamber formed of a lower portion and an upper portion with a
horizontal junction with each other. A seal assembly is interposed at the junction
between the lower and upper housings. A conveyor means is provided to transport
glass sheet substrates through the chamber. A chemical vapor distributor is
located within the deposition chamber to provide a coating on the glass substrate
as the substrate passes through the chamber.
[0005] The system includes a vacuum source for drawing a vacuum within the
deposition chamber. The deposition chamber typically includes elongate heaters
for heating the glass sheets as they are conveyed through the system. The glass
sheets pass into the deposition chamber from a vacuum-heating furnace to the
vacuum deposition chamber that is maintained at a similar vacuum and
temperature setting as the heating furnace. Powdered cadmium sulfide and
powdered cadmium telluride are fed into the vaporization deposition chamber.
The films are then deposited onto the previously coated and heated glass substrates
sequentially. The coated substrates are next transferred through a load lock and
thence into a cooling chamber wherein cooling is effected by compressed nitrogen
and finally conveyed to atmosphere pressure though an exit load lock to an air
cooling section for reduction to ambient temperature. The cadmium telluride thinfilm
material requires a follow-on processing step to re-crystallize its
polycrystalline structure so that effective photovoltaic devices can be made from
the film stack. Typically this step is accomplished by applying a solution of
cadmium chloride to the cadmium telluride surface of the cooled coated glass and
re-heating the glass to a temperature of about 390°C to 420°C for a period of about
15 to 20 minutes. Care must be taken to slowly heat and cool the glass to avoid
breakage during this treatment which extends the overall process time of the
required step.
[0006] Since it is well recognized that renewable energy sources are becoming
increasingly more important, it is deemed that commercial production of
photovoltaic devices for the generation of electrical energy is important in
satisfying the renewable energy needs. The utilization of thin-film coatings of
semiconductor materials on glass substrates is considered to be a viable
mechanism in the field of photovoltaic-based electrical energy generation systems.
[0007] It has been found that thin-film coating systems, based upon the above
referred to technology, are capable of depositing thin film of cadmium
sulfide/cadmium telluride photovoltaic material onto commercially available sodalime
glass substrates in a vacuum. The photovoltaic materials are subsequently
treated to re-crystallize the cadmium telluride surface making the film stack ready
for further processing into photovoltaic devices. While the above-described
system is capable of producing photovoltaic panels suitable for the production of
electrical energy, it would be desirable to reduce the cost for such production to
render the system commercially viable.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to produce a photovoltaic panel
by depositing thin-films of semiconductor materials from chemical vapors on a
substrate at atmospheric pressure.
[0009] Another object of the present invention is to produce a photovoltaic
panel by vaporizing cadmium sulfide and cadmium telluride and depositing the
same on the surface of a heated substrate to form a first thin film of cadmium
sulfide and a second thin film of cadmium telluride at atmospheric pressure.
[0010] Another object of the present invention is to produce a photovoltaic
panel by rapid high temperature re-crystallization of the thin-film cadmium
telluride polycrystalline material to yield high efficiency photovoltaic devices.
[0011] It has surprisingly been found that the above objects may be achieved
by a process for coating a substrate at atmospheric pressure, comprising the steps
of: (1) providing sources of semiconductor materials such as cadmium sulfide or
cadmium telluride; (2) heating and vaporizing the semiconductor materials at
substantially atmospheric pressure, and maintaining the vaporized materials at
temperatures above their temperatures of condensation; and (3) sequentially
depositing the vaporized materials on a heated surface of a substrate such as glass
at substantially atmospheric pressure, to form a laminar structure, Optionally,
while the laminar structure is still substantially at the temperature of deposition
and at substantially atmospheric pressure, a cadmium telluride layer may be
treated with a reactive gas to effect a re-crystallization of the cadmium telluride.
Subsequent processing of the laminar film stack may be accomplished to produce
active thin-film photovoltaic devices.
BRIEF DESCRIPTION OF THE DRAWING
[0012] The above as well as other objects and advantages of the invention will
become readily apparent to those skilled in the art from reading the following
- 3 -
detailed description of a preferred embodiment of the invention in the light of the
accompanying drawing, in which:
[0013] The drawing shows in schematic form the inventive steps of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Referring to the drawing, there is schematically illustrated the steps of
the process for coating a surface of a substrate with a film of cadmium telluride at
atmospheric pressure.
[0015] Individually metered masses of semiconductor material, preferably
cadmium sulfide (CdS) or cadmium telluride (CdTe) in powdered form, are
introduced into a zone which is continuously purged by a stream of inert gas,
preferably nitrogen, flowing between an inlet and an outlet at approximately
atmospheric pressure. The powder is carried from the inlet, by the inert gas
flowing at a controlled rate, into a vaporizer consisting of a heated packed bed in
which the powder is vaporized as it passes through the interstitial voids of the
packed bed's media. The outlet of the heated packed bed is caused to
communicate with the interior of a heated zone to distribute the vaporized material
to the substrate. Alternative powder vaporization methods through which the
metered powder mass and carrier inert gas are heated may be employed for
generating the vaporized material fluid stream. The alternative methods may
include, but are not necessarily limited to, heated fluidized beds in which the
carrier inert gas is heated and the powder is vaporized, thermal "flash" vaporizers
that heat the carrier inert gas and vaporize the powder, and atmospheric pressure
thermal spray units that heat the carrier inert gas and vaporize the powder.
[0016] The fluid, preferably including cadmium sulfide or cadmium telluride
powder and the carrier inert gas, is a high temperature flowing mixture comprising
the carrier inert gas and vaporized material at a temperature above its condensation
temperature. The temperature of the fluid mixture is typically in a range of from
about 800°C to about 1,100°C. The heated fluid mixture is then directed into an
apparatus for producing a laminar flow of constant velocity toward the surface of a
substrate at substantially atmospheric pressure. The substrate is typically a soda-
lime glass, preferably having a low-E coating that is transparent and electrically
conductive. An example of such glass is produced by Pilkington Glass Co. and is
designated as TEC-15. The surface of the substrate is maintained at a temperature
of from about 585°C to about 650°C.
[0017] The apparatus for producing the desired laminar flow of fluid mixture
comprises of a series of individual passageways adapted to cause a series of
velocity changes in the transient fluid as the fluid flows through the passageways.
The apparatus is maintained above the vaporization temperature of the cadmium
sulfide or cadmium telluride, to prevent condensation of the material within the
passageways. Such fluid flow evenly distributes the fluid mixture to an elongate
outlet nozzle, and enables uniform laminar flow at constant mass flow distribution
to flow tangentially of and supplied to the surface of the substrate. The above
action causes the molecules of the fluid mixture to be evenly distributed
throughout the length of the elongate outlet nozzle, and causes the molecules to
travel from the outlet nozzle in a generally parallel path and at a constant velocity,
producing a laminar flow of constant velocity and mass distribution directed
toward the substrate.
[0018] The velocity of the fluid mixture exiting the outlet nozzle may be
regulated by controlling the mass flow rate at which the fluid mixture is
introduced at the inlet.
[0019] In order to control the thin-film deposition rate of the vaporized
material within the fluid emitted from the apparatus being applied to the substrate,
the mass flow rate of the fluid mixture and the velocity of the substrate are
controlled while controlling the temperature of the substrate below the vaporized
material's condensation point. As the heated fluid mixture impinges onto the
cooler substrate, it cools to a temperature below the condensation temperature of
the vaporized material. The material condenses from the fluid mixture, in a
polycrystalline form, onto the moving substrate as a continuous thin-film layer. A
fluid extraction device is disposed upstream and downstream of the outlet nozzle,
to enable the controlled withdrawal of the non-film generating constituents of the
fluid mixture directed to the surfaces of the substrate.
[0020] While there may be a number of different systems for evenly
distributing the vaporized cadmium sulfide or cadmium telluride on the surface of
the transient glass substrate, it is contemplated that the apparatus illustrated and
described in U.S. Patent 4,509,526 to Hofer et al. may provide satisfactory results.
[0021 ] The deposition of any number of consecutive layers of cadmium sulfide
and/or cadmium telluride by the apparatus described above, to prepare a laminar
structure, is contemplated by the present invention.
[0022] Subsequent to the deposition of a cadmium telluride polycrystalline
thin-film, a re-crystallization step would be required to allow the production of
photovoltaic devices from the laminar thin-film stack. It has been found that this
step can be achieved in less than one minute by subjecting the hot cadmium
telluride film to a hot gaseous atmosphere of dilute hydrogen chloride in nitrogen
at substantially one atmosphere of pressure. The ability to control the recrystallization
of the cadmium telluride while maintaining the temperature of the
substrate eliminates cool-down and re-heating of the substrate/fihn-stack assembly
during the re-crystallization step. The use of a "dry" re-crystallization step
eliminates the use of a toxic cadmium chloride solution and its application
apparatus. Typically, a glass substrate exiting the in-line re-crystallization process
would have a temperature from about 620°C to about 630°C. This temperature
range allows the glass to be thermally tempered by cool quenching gas flows as
the substrate/film-stack exits the processing line.
[0023] The above-described process relates to a method for producing a thinfilm
cadmium sulfide/cadmium telluride photovoltaic material on the surface of a
soda-lime glass substrate, to provide large area photovoltaic panels. However, it
must be understood that the concept of atmospheric vapor deposition can be
extended to include other thin-film materials that are normally deposited in a
vacuum.
[0024] Thin-film photovoltaic materials that could be considered are CIGS
(copper-indium-gallium-diselenide), CdS/CIS-alloy (cadmium sulfide/copperindium-
selenium alloy), amorphous silicon or thin-film polycrystalline silicon, and
Zn (O, S, OH)X/CIGS (zinc oxide sulfide hydroxide/copper-indium-galliumdiselenide).
[0025] Other thin-film materials that can be considered for application to glass
substrates are optical coatings such as multi-layer stacks used for very low
emissivity films and anti-reflection films. Other value added features such as
improved durability films, self-cleaning films, photo-optic, and electro-optic films
could be developed using the inventive atmospheric pressure deposition concept.
[0026] The process of atmospheric pressure deposition of thin-film materials
could be applied to a variety of substrate materials for enhancement of their
surface properties. Substrates that could be considered include polymeric
materials, ceramics, metals, wood, and others.

We Claim:
1. A process for coating a substrate heated to a temperature below the condensation temperature of a semiconductor material at atmospheric pressure, comprising the steps of:
mixing a controlled mass of semiconductor material and a heated inert gas stream; vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature above the condensation temperature of the semiconductor material;
directing the fluid mixture at the substrate, wherein the substrate is at atmospheric pressure; and
depositing a layer of the semiconductor material onto a surface of the substrate.
2. The process as claimed in claim 1, wherein the semiconductor material is one of cadmium sulfide and cadmium telluride.
3. The process as claimed in claim 1, wherein the inert gas is nitrogen.
4. The process as claimed in claim 1, wherein the temperature of the fluid mixture ranges from 800 degrees C to 1,100 degrees C.
5. The process as claimed in claim 1, wherein the substrate comprises glass.
6. The process as claimed in claim 5, wherein the glass includes a transparent, electrically conductive coating.
7. The process as claimed in claim 1, wherein the substrate has a temperature ranging from 585 degrees C to 650 degrees C.
8. The process as claimed in claim 1, wherein the steps of vaporizing, directing, and depositing are repeated at least once, to deposit at least one additional layer of semiconductor material on the substrate.
9. A process for coating a substrate heated to a temperature below the condensation temperature of a semiconductor material at atmospheric pressure, comprising the steps of:

mixing a controlled mass of semiconductor material and a heated inert gas stream;
vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature ranging from 800 degrees C to 1,100 degrees C;
directing the fluid mixture at the substrate having a transparent, electrically conductive coating and having a temperature range from 585 degrees C to 650 degrees C and at atmospheric pressure; and
depositing a layer of the semiconductor material onto a surface of the substrate.
10. The process as claimed in claim 9, wherein the steps of vaporizing, directing, and depositing
are repeated at least once, to deposit at least one additional layer of semiconductor material on the
substrate.
11. A process for coating a substrate heated to a temperature below the condensation
temperature of a semiconductor material at atmospheric pressure, comprising the steps of:
mixing a controlled mass of semiconductor material and a heated inert gas stream;
vaporizing the semiconductor material in the heated inert gas stream to create a fluid mixture having a temperature ranging from 800 degrees C to 1,100 degrees C;
directing the fluid mixture at the substrate having a transparent, electrically conductive coating and having a temperature range from 585 degrees C to 650 degrees C and at atmospheric pressure;
depositing a layer of the semiconductor material onto a surface of the substrate; and
repeating the steps of vaporizing, directing, and depositing at least once, to deposit at least one additional layer of semiconductor material onto the substrate.

Documents:

1313-delnp-2007-1-Correspondence Others-(15-05-2012).pdf

1313-delnp-2007-Abstract-(03-12-2012).pdf

1313-DELNP-2007-Abstract-(15-05-2012).pdf

1313-delnp-2007-abstract.pdf

1313-delnp-2007-Assignment-(04-02-2011).pdf

1313-delnp-2007-assignments.pdf

1313-delnp-2007-Claims-(03-12-2012).pdf

1313-DELNP-2007-Claims-(15-05-2012).pdf

1313-delnp-2007-claims.pdf

1313-delnp-2007-Correspondence Others-(03-12-2012).pdf

1313-delnp-2007-Correspondence Others-(08-05-2012).pdf

1313-delnp-2007-Correspondence Others-(08-06-2011).pdf

1313-delnp-2007-Correspondence Others-(08-11-2012).pdf

1313-delnp-2007-Correspondence Others-(11-05-2012).pdf

1313-DELNP-2007-Correspondence Others-(15-05-2012).pdf

1313-delnp-2007-Correspondence Others-(22-05-2012).pdf

1313-delnp-2007-Correspondence Others-(23-05-2011).pdf

1313-delnp-2007-correspondence others-(30-04-2008).pdf

1313-delnp-2007-Correspondence-others (30-04-2008).pdf

1313-delnp-2007-Correspondence-others-(04-02-2011).pdf

1313-delnp-2007-correspondence-others.pdf

1313-delnp-2007-description (complete).pdf

1313-delnp-2007-Drawings-(22-05-2012).pdf

1313-delnp-2007-drawings.pdf

1313-delnp-2007-Form-1-(03-12-2012).pdf

1313-delnp-2007-Form-1-(04-02-2011).pdf

1313-DELNP-2007-Form-1-(15-05-2012).pdf

1313-delnp-2007-form-1.pdf

1313-delnp-2007-Form-18 (30-04-2008).pdf

1313-delnp-2007-form-18-(30-04-2008).pdf

1313-delnp-2007-Form-2-(03-12-2012).pdf

1313-delnp-2007-Form-2-(04-02-2011).pdf

1313-DELNP-2007-Form-2-(15-05-2012).pdf

1313-delnp-2007-form-2.pdf

1313-delnp-2007-Form-3-(08-05-2012).pdf

1313-delnp-2007-Form-3-(08-06-2011).pdf

1313-DELNP-2007-Form-3-(15-05-2012).pdf

1313-delnp-2007-Form-3-(23-05-2011).pdf

1313-delnp-2007-form-3.pdf

1313-delnp-2007-form-5.pdf

1313-delnp-2007-GPA-(04-02-2011).pdf

1313-delnp-2007-pct-notification.pdf

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Patent Number

254713

Indian Patent Application Number

1313/DELNP/2007

PG Journal Number

50/2012

Publication Date

14-Dec-2012

Grant Date

10-Dec-2012

Date of Filing

19-Feb-2007

Name of Patentee

CALYXO GMBH

Applicant Address

OT THALHEIM, SONN,ENALLEE 1 A, BITTERFELD-WOLFEN, GERMANY 06766

Inventors:

#	Inventor's Name	Inventor's Address
1	JOHNSTON,NORMAN,W	25859 WILLOWBEND, PERRYSBURG, OH 43551, USA

PCT International Classification Number

C23C16/453

PCT International Application Number

PCT/US2005/027368

PCT International Filing date

2005-08-02

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	60/602,405	2004-08-18	U.S.A.