# US 8,771,419 B2 · Roll to roll evaporation tool for solar absorber precursor formation

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- Number: US 8,771,419 B2
- Document ID: US8771419B2
- Status: Granted
- Kind: B2
- Application number: 11/868,443
- Filed: 2007-10-05
- Published: 2009-04-09
- Granted: 2014-07-08
- Earliest claimed: 2007-10-05
- Assignees: Solopower Systems, Inc.
- Applicants: Mustafa Pinarbasi; Bulent M. Basol
- Inventors: Mustafa Pinarbasi; Bulent M. Basol
- Web page: https://patentgrep.com/patent/US8771419B2

## CPC

- C23C 14/24: Vacuum evaporation
- C23C 14/0623: {Sulfides, selenides or tellurides}
- C23C 14/562: {for coating elongated substrates}
- H10F 10/167: comprising Group I-III-VI materials, e.g. CdS/CuInSe2 [CIS] heterojunction photovoltaic cells
- H10F 71/137: {Batch treatment of the devices}
- H10F 77/126: {comprising only Group I-III-VI chalcopyrite materials, e.g. CuInSe2, CuGaSe2 or CuInGaSe2 [CIGS]}
- H10F 77/1265: {characterised by the dopants}
- H10F 77/1694: {the films including Group I-III-VI materials, e.g. CIS or CIGS}
- H10P 14/203: {using transformation of metal, e.g. oxidation or nitridation}
- H10P 14/3436: {being chalcogenide semiconductor materials not being oxides, e.g. ternary compounds}
- H10P 14/3441: {Conductivity type}
- Y02E 10/541: CuInSe2 material PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

An evaporation tool for forming a dopant structure on a front surface of a continuous workpiece, wherein the front surface includes a precursor layer to form Group IBIIIAVIA absorbers for solar cells and the dopant structure is used to introduce dopants into the precursor layer. The tool includes at least a first vapor source station to deposit a Group VIA material, such as Se, and a second vapor station to deposit a dopant material, such as Na, onto the continuous workpiece. A moving assembly of the tool holds and moves the continuous workpiece within the tool by feeding the continuous workpiece from a first end and taking up from a second end of the tool. A support assembly of the tool contacts a back surface of the continuous workpiece to remove the heat from and apply tension to the continuous workpiece during the process.

## Claims

### Claim 1

A system for forming a dopant structure on a frontside of a continuous flexible workpiece, wherein the frontside includes a precursor layer and the dopant structure provides a dopant material that subsequently dopes a solar cell absorber formed by a reaction of the precursor layer and the dopant structure, the system comprising:
a process chamber including a first vapor source station to deposit one of Se material and Na material and a second vapor source station to deposit the other of the Se material and the Na material onto the precursor layer and to form the dopant structure on processed portions of the continuous flexible workpiece, wherein the processed portions of the continuous flexible workpiece provide a protective top surface for the underlying precursor layer;
a moving assembly to hold and move the continuous flexible workpiece within and through the process chamber, including a portion of the continuous flexible workpiece disposed within and being processed by the first and second vapor source stations, by feeding previously unrolled portions of the continuous flexible workpiece from an input end of the process chamber and taking up and wrapping the processed portions of the continuous flexible workpiece at an output end of the process chamber, wherein the protective top surface contacts portions of a backside of the continuous flexible workpiece as the processed portions of the continuous flexible workpiece are wrapped, thereby protecting the precursor layer therebelow, and wherein the moving assembly does not contain any element that contacts a frontside of the continuous flexible workpiece; and
a support assembly that supports by contacting the backside other portions of the continuous flexible workpiece that are disposed within the process chamber, wherein the support assembly includes components that remove the heat from the backside of the other portions of the continuous flexible workpiece that are disposed within the process chamber and prevent any reaction from occurring on the processed portions of the continuous flexible workpiece and thereby avoid formation of the absorber, wherein the components of the support assembly include a set of rollers that each contacts the backside of the continuous flexible workpiece aligned along a curved path within the process chamber, such that none of the components of the support assembly contact the frontside of the continuous flexible workpiece, and wherein the support assembly does not contain any element that contacts the frontside of the continuous flexible workpiece.

### Claim 2 (depends on 1)

The system of claim 1, wherein the moving assembly comprises a feed roller adjacent the input end and take-up roller adjacent the output end of the process chamber, wherein the continuous flexible workpiece is unwrapped from the feed roller and wrapped by the take-up roller.

### Claim 3 (depends on 1)

The system of claim 1, wherein each roller tensions the continuous flexible workpiece by applying a pressure perpendicular to a backside portion where each roller touches.

### Claim 4 (depends on 3)

The system of claim 3, wherein the rollers are biased towards the backside portion by a biasing system including a series of springs.

### Claim 5 (depends on 4)

The system of claim 4, wherein the rollers are cooled by a cooling system.

### Claim 6 (depends on 1)

The system of claim 1 further including a third vapor source station disposed within the process chamber to deposit Se onto the frontside of the continuous flexible workpiece.

### Claim 7 (depends on 1)

The system of claim 1, wherein the components of the support assembly are cooled by a cooling system.

### Claim 8 (depends on 1)

The system of claim 1 wherein the first and second vapor source stations are maintained at a pressure of 10−4- 10−6 Torr during the process.

### Claim 9 (depends on 1)

The system of claim 1 wherein the first and second vapor source stations are activated at the same time.

### Claim 10 (depends on 1)

The system of claim 1 wherein the first and second vapor source stations are activated sequentially.