Patents Assigned to Crystal Solar Incorporated
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Patent number: 9982363Abstract: A system for depositing thin single crystal silicon wafers by epitaxial deposition in a silicon precursor depletion mode with cross-flow deposition may include: a substrate carrier with low total heat capacity, high emissivity and small volume; a lamp module with rapid heat-up, efficient heat production, and spatial control over heating; and a manifold designed for cross-flow processing. Furthermore, the substrate carrier may include heat reflectors to control heat loss from the edges of the carrier and/or heat chokes to thermally isolate the carrier from the manifolds, allowing independent temperature control of the manifolds. The carrier and substrates may be configured for deposition on both sides of the substrates—the substrates having release layers on both sides and the carriers being configured to have equal process gas flow over both surfaces of the substrate. High volume may be addressed by a deposition system comprising multiple mini-batch reactors.Type: GrantFiled: February 3, 2016Date of Patent: May 29, 2018Assignee: Crystal Solar, IncorporatedInventors: Visweswaren Sivaramakrishnan, Tirunelveli S. Ravi, Andrzej Kaszuba, Quoc Vinh Truong, Jean R. Vatus
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Patent number: 9920451Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize deposition on the chamber walls. Sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: GrantFiled: March 17, 2014Date of Patent: March 20, 2018Assignee: Crystal Solar IncorporatedInventors: Visweswaren Sivaramakrishnan, Kedarnath Sangam, Tirunelveli S. Ravi, Andrzej Kaszuba, Quoc Vinh Truong
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Patent number: 9556522Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize wall deposition. In addition, sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: GrantFiled: March 4, 2014Date of Patent: January 31, 2017Assignee: Crystal Solar IncorporatedInventors: Visweswaren Sivaramakrishnan, Kedarnath Sangam, Tirunelveli S. Ravi, Andrzej Kaszuba, Quoc Vinh Truong
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Patent number: 9397239Abstract: Fabrication of a single crystal silicon solar cell with an insitu epitaxially deposited very highly doped p-type silicon back surface field obviates the need for the conventional aluminum screen printing step, thus enabling a thinner silicon solar cell because of no aluminum induced bow in the cell. Furthermore, fabrication of a single crystal silicon solar cell with insitu epitaxial p-n junction formation and very highly doped n-type silicon front surface field completely avoids the conventional dopant diffusion step and one screen printing step, thus enabling a cheaper manufacturing process.Type: GrantFiled: December 17, 2013Date of Patent: July 19, 2016Assignee: Crystal Solar, IncorporatedInventors: Tirunelveli S. Ravi, Ashish Asthana
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Patent number: 9255346Abstract: A system for depositing thin single crystal silicon wafers by epitaxial deposition in a silicon precursor depletion mode with cross-flow deposition may include: a substrate carrier with low total heat capacity, high emissivity and small volume; a lamp module with rapid heat-up, efficient heat production, and spatial control over heating; and a manifold designed for cross-flow processing. Furthermore, the substrate carrier may include heat reflectors to control heat loss from the edges of the carrier and/or heat chokes to thermally isolate the carrier from the manifolds, allowing independent temperature control of the manifolds. The carrier and substrates may be configured for deposition on both sides of the substrates—the substrates having release layers on both sides and the carriers being configured to have equal process gas flow over both surfaces of the substrate. High volume may be addressed by a deposition system comprising multiple mini-batch reactors.Type: GrantFiled: May 29, 2012Date of Patent: February 9, 2016Assignee: Crystal Solar, IncorporatedInventors: Visweswaren Sivaramakrishnan, Tirunelveli S. Ravi, Andrzej Kaszuba, Bozena Kaszuba, Quoc Vinh Truong, Jean R. Vatus
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Patent number: 9257284Abstract: Methods are described for fabricating HIT solar cells, including double heterojunction and hybrid heterojunction-homojunction solar cells, with very thin single crystal silicon wafers, where the silicon wafer may be less than 80 microns thick, and even less than 50 microns thick. The methods overcome potential issues with handling these very thin wafers by using a process including epitaxial silicon deposition on a growth substrate, partial cell fabrication, attachment to a support substrate and then separation from the growth substrate. Some embodiments of the present invention may include a solar cell device architecture comprising the combination of a heterostructure on the front side of the device with a homojunction at the rear of the device. Furthermore, device performance may be enhanced by including a dielectric stack on the backside of the device for reflecting long wavelength infrared radiation.Type: GrantFiled: January 14, 2013Date of Patent: February 9, 2016Assignee: Crystal Solar, IncorporatedInventor: Kramadhati V. Ravi
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Publication number: 20140318442Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration and the wafers may be mounted at a small angle to the plane of the wafer carrier plates, wherein the wafers are configured in pairs along the direction of gas flow and wherein along the direction of gas flow the angular mounting of the wafers provides a smaller gap between opposed wafer surfaces on said parallel wafer carrier plates in the center of said wafer sleeve than at the periphery of said wafer sleeve.Type: ApplicationFiled: March 17, 2014Publication date: October 30, 2014Applicant: Crystal Solar IncorporatedInventors: Visweswaren Sivaramakrishnan, Jean Vatus, Andrzej Kaszuba, Vicente Lim, Ashish Asthana
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Publication number: 20140311403Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize deposition on the chamber walls. Sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: ApplicationFiled: March 17, 2014Publication date: October 23, 2014Applicant: Crystal Solar, IncorporatedInventors: Visweswaren Sivaramakrishnan, Kedarnath Sangam, Tirunelveli S. Ravi, Andrzej Kaszuba, Quoc Vinh Truong
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Publication number: 20140295106Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize wall deposition. In addition, sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: ApplicationFiled: March 4, 2014Publication date: October 2, 2014Applicant: CRYSTAL SOLAR, INCORPORATEDInventors: Visweswaren Sivaramakrishnan, Kedarnath SANGAM, Tirunelveli S. RAVI, Andrzej KASZUBA, Quoc VINH
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Patent number: 8809097Abstract: Passivated emitter rear local epitaxy (PERL-e) thin Si solar cells may be formed with a heavily doped epitaxial back surface field (BSF) layer, which is patterned to form well spaced point contacts to the silicon base on the rear of the solar cell. The back side of the cell may be finished with a dielectric passivation layer and a metallization layer for making electrical contact to the cell. PERL-e thick Si solar cells may be formed with heavily doped epitaxial films as the back point contacts, where the point contacts are defined by the provision of a selectively patterned thermal oxide on the rear wafer surface. Furthermore, absorption of longer wavelength, infrared (IR), light in thin silicon solar cells may be improved by the addition of a dielectric stack on the rear surface of the solar cell (a back reflector).Type: GrantFiled: September 22, 2011Date of Patent: August 19, 2014Assignee: Crystal Solar IncorporatedInventors: Kramadhati V. Ravi, Tirunelveli S. Ravi
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Patent number: 8663753Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize wall deposition. In addition, sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: GrantFiled: October 30, 2012Date of Patent: March 4, 2014Assignee: Crystal Solar IncorporatedInventors: Visweswaren Sivaramakrishnan, Kedarnath Sangam, Tirunelveli S. Ravi, Andrzej Kaszuba, Quoc Vinh
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Publication number: 20130180578Abstract: Methods are described for fabricating HIT solar cells, including double heterojunction and hybrid heterojunction-homojunction solar cells, with very thin single crystal silicon wafers, where the silicon wafer may be less than 80 microns thick, and even less than 50 microns thick. The methods overcome potential issues with handling these very thin wafers by using a process including epitaxial silicon deposition on a growth substrate, partial cell fabrication, attachment to a support substrate and then separation from the growth substrate. Some embodiments of the present invention may include a solar cell device architecture comprising the combination of a heterostructure on the front side of the device with a homojunction at the rear of the device. Furthermore, device performance may be enhanced by including a dielectric stack on the backside of the device for reflecting long wavelength infrared radiation.Type: ApplicationFiled: January 14, 2013Publication date: July 18, 2013Applicant: Crystal Solar, IncorporatedInventor: Crystal Solar, Incorporated
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Patent number: 8481357Abstract: A method for fabricating a photovoltaic (PV) cell panel wherein all PV cells are formed simultaneously on a two-dimensional array of monocrystalline silicon mother wafers affixed to a susceptor is disclosed. Porous silicon separation layers are anodized in the surfaces of the mother wafers. The porous film is then smoothed to form a suitable surface for epitaxial film growth. An epitaxial reactor is used to grow n- and p-type films forming the PV cell structures. A glass/ceramic handling layer is then formed on the PV cell structures. The PV cell structures with handling layers are then exfoliated from the mother wafer. The array of mother wafers may be reused multiple times, thereby reducing materials costs for the completed solar panels. The glass/ceramic handling layers provide structural integrity to the thin epitaxial solar cells during the separation process and subsequent handling.Type: GrantFiled: April 23, 2010Date of Patent: July 9, 2013Assignee: Crystal Solar IncorporatedInventors: Ananda H. Kumar, Tirunelveli S. Ravi, Vidyut Gopal
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Publication number: 20130065350Abstract: A design and manufacturing method for an interdigitated backside contact photovoltaic (PV) solar cell less than 100 ?m thick are disclosed. A porous silicon layer is formed on a wafer substrate. Portions of the PV cell are then formed using diffusion, epitaxy and autodoping from the substrate. All backside processing of the solar cell (junctions, passivation layer, metal contacts to the N+ and P+ regions) is performed while the thin epitaxial layer is attached to the porous layer and substrate. After backside processing, the wafer is clamped and exfoliated. The front of the PV cell is completed from the region of the wafer near the exfoliation fracture layer, with subsequent removal of the porous layer, texturing, passivation and deposition of an antireflective coating. During manufacturing, the cell is always supported by either the bulk wafer or a wafer chuck, with no processing of bare thin PV cells.Type: ApplicationFiled: October 30, 2012Publication date: March 14, 2013Applicant: Crystal Solar, IncorporatedInventor: Crystal Solar, Incorporated
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Publication number: 20130059430Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize wall deposition. In addition, sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: ApplicationFiled: October 30, 2012Publication date: March 7, 2013Applicant: Crystal Solar, IncorporatedInventor: Crystal Solar, Incorporated
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Patent number: 8298629Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize wall deposition. In addition, sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: GrantFiled: February 25, 2009Date of Patent: October 30, 2012Assignee: Crystal Solar IncorporatedInventors: Visweswaren Sivaramakrishnan, Kedarnath Sangam, Tirunelveli S. Ravi, Andrzej Kaszuba, Quoc Vinh Truong
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Publication number: 20110300715Abstract: A method for fabricating a photovoltaic (PV) cell panel wherein all PV cells are formed simultaneously on a two-dimensional array of monocrystalline silicon mother wafers affixed to a susceptor is disclosed. Porous silicon separation layers are anodized in the surfaces of the mother wafers. The porous film is then smoothed to form a suitable surface for epitaxial film growth. An epitaxial reactor is used to grow n- and p-type films forming the PV cell structures. Contacts to the n- and p-layers are deposited, followed by gluing of a glass layer to the PV cell array. The porous silicon film is then separated by exfoliation in a peeling motion across all the cells attached together above, followed by attaching a strengthening layer on the PV cell array. The array of mother wafers may be reused multiple times, thereby reducing materials costs for the completed solar panels.Type: ApplicationFiled: March 17, 2011Publication date: December 8, 2011Applicant: Crystal Solar, IncorporatedInventors: Tirunelveli S. Ravi, Ananda H. Kumar, Ashish Asthana, Visweswaren Sivaramakrishnan
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Publication number: 20100263587Abstract: An epitaxial reactor enabling simultaneous deposition of thin films on a multiplicity of wafers is disclosed. During deposition, a number of wafers are contained within a wafer sleeve comprising a number of wafer carrier plates spaced closely apart to minimize the process volume. Process gases flow preferentially into the interior volume of the wafer sleeve, which is heated by one or more lamp modules. Purge gases flow outside the wafer sleeve within a reactor chamber to minimize deposition on the walls of the chamber. In addition, sequencing of the illumination of the individual lamps in the lamp module may further improve the linearity of variation in deposition rates within the wafer sleeve. To improve uniformity, the direction of process gas flow may be varied in a cross-flow configuration. Combining lamp sequencing with cross-flow processing in a multiple reactor system enables high throughput deposition with good film uniformities and efficient use of process gases.Type: ApplicationFiled: February 25, 2010Publication date: October 21, 2010Applicant: Crystal Solar, IncorporatedInventors: Visweswaren Sivaramakrishnan, Kedarnath Sangam, Tirunelveli S. Ravi, Andrzej Kaszuba, Quoc Vinh Truong