Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`CANADIAN SOLAR INC.,
`Petitioner,
`
`v.
`
`MAXEON SOLAR PTE. LTD.
`Patent Owner
`
`Patent No. 8,878,053
`Issued: November 4, 2014
`Filed: June 13, 2012
`Inventor: Peter John Cousins
`Title: Front Contact Solar Cell with Formed Emitter
`Inter Partes Review No. IPR2024-01040
`
`DECLARATION OF SANJAY BANERJEE REGARDING
`U.S. PATENT NO. 8,878,053
`________________________
`
`Petitioner Canadian Solar Inc. - Ex. 1003, p. Cover-1
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`

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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`I, Sanjay Banerjee, do hereby declare and state, that all statements made
`
`herein of my own knowledge are true and that all statements made on information
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`and belief are believed to be true; and further that these statements were made with
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`the knowledge that willful false statements and the like so made are punishable by
`
`fine or imprisonment, under Section 1001 of Title 18 of the United States Code.
`
`Executed on: June 24, 2024
`
`___________________________
`
`Sanjay Banerjee
`
`Petitioner Canadian Solar Inc. - Ex. 1003, p. Signature-1
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`TABLE OF CONTENTS
`
`I.
`
`II.
`
`Page
`INTRODUCTION ......................................................................................... 1
`A.
`Engagement ........................................................................................... 1
`B.
`Background and Qualifications ............................................................. 1
`C.
`Compensation and Prior Testimony ...................................................... 4
`D.
`Information Considered ......................................................................... 4
`LEGAL STANDARDS FOR PATENTABILITY ...................................... 5
`A.
`Anticipation ........................................................................................... 6
`B.
`Obviousness ........................................................................................... 8
`III. THE 053 PATENT ....................................................................................... 14
`A.
`The Person Of Ordinary Skill in the Art ............................................. 14
`B.
`053 Patent’s Effective Filing Date ...................................................... 15
`C.
`053 Patent’s Specification ................................................................... 15
`D.
`053 Patent’s Claims ............................................................................. 20
`E.
`The 053 Patent’s Prosecution History ................................................. 23
`F.
`Known Technologies That the Examiner Did Not Consider .............. 25
`G.
`PTAB’s Unpatentability Decisions in Two Continuation
`Applications ......................................................................................... 31
`IV. CLAIM CONSTRUCTION ........................................................................ 32
`V.
`OVERVIEW OF THE PRIOR ART ......................................................... 33
`A.
`Prior Art Status .................................................................................... 33
`B.
`EP1732142A1 to Froitzheim (EX1006) .............................................. 35
`C.
`Gan (EX1007) ..................................................................................... 37
`D.
`Kwark (EX1008) ................................................................................. 40
`E.
`Borden (EX1009) ................................................................................ 42
`
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`VI. FROITZHEIM AND GAN WOULD HAVE RENDERED
`CLAIMS 9-11, 14, 16-17, AND 19-20 OBVIOUS ..................................... 43
`A. Motivation to Modify Froitzheim with Gan........................................ 44
`B.
`Reasonable Expectation of Success .................................................... 51
`C.
`Froitzheim and Gan Disclosed All Claimed Steps .............................. 52
`1. Claim 9 ..........................................................................................52
`2. Claim 10 – P-type dopants ............................................................61
`3. Claim 11 – Borosilicate glass........................................................61
`4. Claim 14 ........................................................................................62
`5. Claim 16 ........................................................................................67
`6. Claim 17 – First dopant source .....................................................68
`7. Claims 19 and 20 – Texturing and Antireflective Layer ..............69
`VII. CLAIMS 11-13, 15 AND 18 ARE UNPATENTABLE OVER
`FROITZHEIM AND GAN IN FURTHER VIEW OF HARTITI
`OR SIVOTHTHAMAN .............................................................................. 69
`1. Claim 12 – Second dopant source layer ........................................69
`2. Claim 13 – Phosphorus .................................................................75
`3. Claim 18 – Second dopant source .................................................76
`4. Claim 11 – Borosilicate glass........................................................76
`5. Claim 15 – In situ ..........................................................................78
`VIII. CLAIMS 9-11, 14, 16-17, AND 19-20 ARE UNPATENTABLE
`OVER FROITZHEIM AND KWARK ..................................................... 80
`A. Motivation to Modify Froitzheim and Kwark ..................................... 80
`B.
`Reasonable Expectation of Success .................................................... 82
`C.
`Froitzheim and Kwark Disclosed All Elements .................................. 83
`1. Claim 9 ..........................................................................................83
`2. Claim 10 – P-type dopants ............................................................85
`3. Claim 14 ........................................................................................85
`4. Claim 16 ........................................................................................85
`
`ii
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`5. Claim 17 – First dopant source .....................................................86
`6. Claims 19 and 20 – Texturing and anti-reflective layer ...............86
`IX. CLAIMS 11-13, 15 AND 18 ARE UNPATENTABLE OVER
`FROITZHEIM AND KWARK IN FURTHER VIEW OF
`HARTITI OR SIVOTHTHAMAN ............................................................ 87
`1. Claim 12 – Second dopant source layer ........................................87
`2. Claim 13 – Phosphorus .................................................................88
`3. Claim 18 – Second dopant source .................................................88
`4. Claim 11 – Borosilicate glass........................................................89
`5. Claim 15 – In situ ..........................................................................89
`OBJECTIVE FACTORS SUPPORT OBVIOUSNESS ........................... 89
`A.
`No Commercial Success Attributable to the 516 Patent ..................... 89
`B.
`No Evidence of Unexpected Results ................................................... 97
`
`X.
`
`iii
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`Petitioner Canadian Solar Inc. - Ex. 1003, p. iii
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`I.
`
`INTRODUCTION
`A.
`Engagement
`1.
`I have been retained by counsel for Canadian Solar Inc. (“CSI” or
`
`“Petitioner”) as an expert witness in the above-captioned proceeding. I have been
`
`asked to provide my opinions about the state of the art of the technology related to
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`U.S. Patent No. 8,878,053 (“the 053 Patent”) (EX1001) and on the patentability of
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`claims 9-20 of this patent. The following is my written declaration on these topics.
`
`B.
`2.
`
`Background and Qualifications
`I currently serve as the Cockrell Family Regents Chair Professor of
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`Electrical and Computer Engineering and Director of the Microelectronics
`
`Research Center at the University of Texas at Austin (“UT”). Prior to this
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`position, I was first an Assistant Professor (September 1987 - August 1990) and
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`later an Associate Professor (September 1990 - August 1993) at UT, before being
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`named a Professor in September 1993. Prior to starting my academic work at UT,
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`I was a member of the technical staff at Texas Instruments (Corporate R&D) from
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`the time I completed my doctoral studies in 1983 until August 1987.
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`3.
`
`I received my Ph.D. in Electrical Engineering from the University of
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`Illinois in 1983. I also received an M.S. in Electrical Engineering from the
`
`University of Illinois in 1981. I received a B. Tech. in Electronics from the Indian
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`Institute of Technology at Kharagpur in 1979.
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`4.
`
`I have more than 40 years of experience in the field of electrical
`
`engineering, including extensive experience in semiconductor development and
`
`fabrication including that of solar cells, passivation, and dielectric materials. For
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`example, I am a named author on 24 publications and conference proceedings
`
`relating to solar cells, as can be seen from my CV EX1004.
`
`5.
`
`I am a Fellow of the Institute of Electrical and Electronics Engineers
`
`(“IEEE”), the American Physical Society (“APS”), and the American Association
`
`for the Advancement of Science (“AAAS”). I have served on numerous
`
`professional and government committees in the electrical engineering field,
`
`including chairing multiple IEEE committees, meetings, and programs, serving on
`
`Morgan & Claypool’s editorial board, and serving as a member on the
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`International Technology Roadmap for Semiconductors (“ITRS”).
`
`6.
`
`I have taught courses in Semiconductor Physics, Solid State
`
`Electronic Devices, and Microelectronic Device Fabrication at UT. In particular, I
`
`have taught an undergraduate course every year for 30 years on Semiconductor
`
`Devices out of a textbook, “Solid State Electronic Devices,” by Ben Streetman and
`
`Sanjay Banerjee (ISBN 0-13-335603). Several of my lectures out of the textbook
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`relate to solar cells. In addition, I have delivered many courses to industry
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`professionals on Semiconductor Devices and Memory and Semiconductor
`
`
`
`2
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`Processing. As a principal investigator, I have been the advisor to over 80
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`Doctoral and Masters students.
`
`7.
`
`I am the co-author of several books and invited book chapters
`
`covering the area of electronic and semiconductor devices, including: Dopant
`
`Diffusion, Solid State Electronic Devices (three editions). I have authored or
`
`coauthored more than 1,000 papers and presentations in the areas of semiconductor
`
`devices and electronics development over the course of my career.
`
`8.
`
`I have been the recipient of fifty grants to fund my research from a
`
`variety of funding agencies, including the National Science Foundation (“NSF”),
`
`DARPA, the Department of Energy, Semiconductor Research Corporation, the
`
`Department of Defense-Multidisciplinary University Research Initiative, and the
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`Office of Naval Research. A number of the sponsored research grants on which I
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`have been a principal or coinvestigator have related to solar cells and various
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`deposition techniques for optoelectronic devices, including for example,
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`“Optoelectronic Devices by Photo-enhanced Chemical Vapor Deposition,”
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`(National Science Foundation, August 1988-July 1993).
`
`9.
`
`I have received numerous other awards recognizing my extensive
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`work in the electrical engineering field. For example, I was on the Advisory
`
`Board, and the Silicon Solar Cell Thrust Lead for the Bay Area Photovoltaics
`
`
`
`3
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`Consortium funded by the U.S. Department of Energy. This and other awards are
`
`described in more detail in my CV. EX1004.
`
`C. Compensation and Prior Testimony
`I am being compensated at a rate of $650.00 per hour for my time
`10.
`
`spent on this matter. I am also being reimbursed for reasonable and customary
`
`expenses associated with my work in this matter. My compensation is not
`
`contingent on the outcome of this matter or the specifics of my testimony.
`
`11.
`
`I have previously submitted declarations in multiple IPR proceedings
`
`and have testified also as an expert witness in Federal Court and the ITC, as
`
`summarized in EX1004 at 1.
`
`Information Considered
`D.
`12. My opinions are based on my years of education, research and
`
`experience, as well as my investigation and study of relevant materials. In forming
`
`my opinions, I have considered the materials I identify in this declaration and those
`
`listed as exhibits in Appendix B, attached to this declaration.
`
`13.
`
`I may rely upon these materials and/or additional materials to respond
`
`to arguments raised by the Patent Owner. I may also consider additional
`
`documents and information in forming any necessary opinions—including
`
`documents that may not yet have been provided to me.
`
`
`
`4
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`14. My analysis of the materials produced in this investigation is ongoing
`
`and I will continue to review any new material as it is provided. This declaration
`
`represents only those opinions I have formed to date. I reserve the right to revise,
`
`supplement, and/or amend my opinions stated herein based on new information
`
`and on my continuing analysis of the materials already provided.
`
`II. LEGAL STANDARDS FOR PATENTABILITY
`I am not a lawyer and am not providing any legal opinions. In
`15.
`
`providing my opinions in this declaration, I am relying upon certain basic legal
`
`principles that have been explained to me by counsel and which I am summarizing
`
`below.
`
`16. First, I understand that for an invention claimed in a patent to be
`
`found patentable, it must be, among other things, new and not obvious from what
`
`was known before the invention was made.
`
`17.
`
`I understand the information that is used to evaluate whether an
`
`invention is new and not obvious is generally referred to as “prior art” and
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`generally includes patents and printed publications (e.g., books, journal
`
`publications, articles on websites, product manuals, etc.).
`
`18.
`
`I understand that in this proceeding the Petitioner has the burden of
`
`proving that the claims are anticipated by or obvious from the prior art by a
`
`
`
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`preponderance of the evidence. I understand that “a preponderance of the
`
`evidence” is evidence sufficient to show that a fact is more likely true than it is not.
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`19.
`
`I understand that in this proceeding, the claims should be given their
`
`ordinary and accustomed meaning as understood by one of ordinary skill in the art
`
`in view of the patent and its file history. The claims after being construed in this
`
`manner are then to be compared to the information in the prior art.
`
`20.
`
`I understand that in this proceeding, the information that may be
`
`evaluated is limited to patents and printed publications. My analysis below
`
`compares the claims to patents and printed publications that are prior art to the
`
`claims.
`
`21.
`
`I understand that there are various ways in which prior art may render
`
`a patent claim unpatentable based on prior art patents and printed publications.
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`First, the prior art can be shown to “anticipate” the claim. Second, the prior art can
`
`be shown to have made the claim “obvious” to a person of ordinary skill in the art.
`
`My understanding of the legal standards is set forth below.
`
`A. Anticipation
`I understand that the following standards govern the determination of
`22.
`
`whether a patent claim is “anticipated” by the prior art.
`
`23.
`
`I have applied these standards in my evaluation of whether the claims
`
`would have been anticipated by the prior art.
`
`
`
`6
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`24.
`
`I understand that the “prior art” includes patents and printed
`
`publications that existed before the earliest filing date (the “effective filing date”)
`
`of the claim in the patent. I also understand that a patent will be prior art if it was
`
`filed before the effective filing date of the claimed invention, while a printed
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`publication will be prior art if it was publicly available before that date.
`
`25.
`
`I understand that, for a patent claim to be “anticipated” by the prior
`
`art, each and every requirement of the claim must be found, expressly or
`
`inherently, in a single prior art reference as recited in the claim. I understand that
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`claim limitations that are not expressly described in a prior art reference may still
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`be there if they are “inherent” to the thing or process being described in the prior
`
`art. I understand that a limitation can be “inherent” if that limitation is necessarily
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`present in or the natural result of the elements explicitly disclosed by the prior art.
`
`26.
`
`I understand that if a reference incorporates other documents by
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`reference, the incorporating reference and the incorporated reference(s) should be
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`treated as a single prior art reference for purposes of analyzing anticipation.
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`27.
`
`I understand that it is acceptable to consider evidence other than the
`
`information in a particular prior art document to determine if a feature is
`
`necessarily present in or inherently described by that reference.
`
`
`
`7
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`B. Obviousness
`I understand that a claimed invention is not patentable if it would have
`28.
`
`been obvious to a person of ordinary skill in the field of the invention at the time
`
`the invention was made.
`
`29.
`
`I understand that the obviousness standard is defined in the patent
`
`statute (35 U.S.C. § 103(a)) as follows:
`
`30. A patent may not be obtained though the invention is not identically
`
`disclosed or described if the differences between the subject matter sought to be
`
`patented and the prior art are such that the subject matter as a whole would have
`
`been obvious at the time the invention was made to a person having ordinary skill
`
`in the art to which said subject matter pertains. Patentability shall not be negatived
`
`by the manner in which the invention was made.
`
`31.
`
`I understand that the following standards govern the determination of
`
`whether a claim in a patent is obvious. I have applied these standards in my
`
`evaluation of whether the claims would have been considered obvious as of the
`
`priority date of the patent.
`
`32.
`
`I understand that to find a claim in a patent obvious, one must make
`
`certain findings regarding the claimed invention and the prior art. Specifically, I
`
`understand that the obviousness question requires consideration of four factors
`
`(although not necessarily in the following order):
`
`
`
`8
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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` The scope and content of the prior art;
` The differences between the prior art and the claims at issue;
` The knowledge of a person of ordinary skill in the pertinent art; and
` Whatever objective factors indicating obviousness or non-obviousness
`may be present in any particular case.
`In addition, I understand that the obviousness inquiry should not be
`
`33.
`
`done in hindsight, but must be done using the perspective of a person of ordinary
`
`skill in the relevant art as of the effective filing date of the patent claim.
`
`34.
`
`I understand the objective factors indicating obviousness or non-
`
`obviousness may include: commercial success of products covered by the patent
`
`claims; a long-felt need for the invention; failed attempts by others to make the
`
`invention; copying of the invention by others in the field; unexpected results
`
`achieved by the invention; praise of the invention by those in the field; the taking
`
`of licenses under the patent by others; expressions of surprise by experts and those
`
`skilled in the art at the making of the invention; and the patentee proceeded
`
`contrary to the accepted wisdom of the prior art. I also understand that any of this
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`evidence must be specifically connected to the invention rather than being
`
`associated with the prior art or with marketing or other efforts to promote an
`
`invention. I am not presently aware of any evidence of “objective factors”
`
`suggesting the claimed methods are not obvious, and reserve my right to address
`
`any such evidence if it is identified in the future.
`
`
`
`9
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`35.
`
`I understand the combination of familiar elements according to known
`
`methods is likely to be obvious when it does no more than yield predictable results.
`
`I understand that when the prior art does not expressly disclose a claim limitation,
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`inherency may also supply a missing claim limitation in an obviousness analysis. I
`
`understand that inherency is established in the context of obviousness when the
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`limitation at issue necessarily must be present, or the natural result of the
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`combination of elements explicitly disclosed by the prior art. I also understand
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`that an example of a solution in one field of endeavor may make that solution
`
`obvious in another related field. I also understand that market demands or design
`
`considerations may prompt variations of a prior art system or process, either in the
`
`same field or a different one, and that these variations will ordinarily be considered
`
`obvious variations of what has been described in the prior art.
`
`36.
`
`I also understand that if a person of ordinary skill can implement a
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`predictable variation, that variation would have been considered obvious. I
`
`understand that for similar reasons, if a technique has been used to improve one
`
`device, and a person of ordinary skill in the art would recognize that it would
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`improve similar devices in the same way, using that technique to improve the other
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`device would have been obvious unless its actual application yields unexpected
`
`results or challenges in implementation.
`
`
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`10
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`37.
`
`I understand that the obviousness analysis need not seek out precise
`
`teachings directed to the specific subject matter of the challenged claim, but
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`instead can take account of the “ordinary innovation” and experimentation that
`
`does no more than yield predictable results, which are inferences and creative steps
`
`that a person of ordinary skill in the art would employ.
`
`38.
`
`I understand that sometimes it will be necessary to look to interrelated
`
`teachings of multiple patents/publications; the effects of demands known to the
`
`design community or present in the marketplace; and the background knowledge
`
`possessed by a person having ordinary skill in the art. I understand that all these
`
`issues may be considered to determine whether there was an apparent reason to
`
`combine the known elements in the fashion claimed by the patent at issue.
`
`39.
`
`I understand that the obviousness analysis cannot be confined by a
`
`formalistic conception of the words “teaching, suggestion, and motivation.” I
`
`understand that in 2007, the Supreme Court issued its decision in KSR Int'l Co. v.
`
`Teleflex, Inc., 550 U.S. 398, 418 (2007), where the Court rejected the previous
`
`requirement of a “teaching, suggestion, or motivation to combine” known elements
`
`of prior art for purposes of an obviousness analysis as a precondition for finding
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`obviousness. It is my understanding that KSR confirms that any motivation that
`
`would have been known to a person of skill in the art, including common sense, or
`
`
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`derived from the nature of the problem to be solved, is sufficient to explain why
`
`references would have been combined.
`
`40.
`
`I understand that a person of ordinary skill attempting to solve a
`
`problem will not be led only to those elements of prior art designed to solve the
`
`same problem. I understand that under the KSR standard, steps suggested by
`
`common sense are important and should be considered. Common sense teaches
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`that familiar items may have obvious uses beyond the particular application being
`
`described in a reference, that if something can be done once it is obvious to do it
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`multiple times, and in many cases a person of ordinary skill will be able to fit the
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`teachings of multiple patents/publications together like pieces of a puzzle. As
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`such, the prior art considered can be directed to any need or problem known in the
`
`field of endeavor and can provide a reason for combining the elements of the prior
`
`art in the manner claimed. In other words, the prior art does not need to be
`
`directed towards solving the same problem that is addressed in the patent. Further,
`
`the individual prior art references themselves need not all be directed towards
`
`solving the same problem.
`
`41.
`
`I understand that obviousness does not require that the features of a
`
`secondary reference be bodily incorporated into the structure of the primary
`
`reference. Rather, the test is what the combined teachings of those references
`
`would have suggested to a Skilled Artisan. The disclosures of the prior art
`
`
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`references need not be physically combinable. Combining the teachings of
`
`references should be the focus of the analysis.
`
`42.
`
`I understand that an invention that might be considered an obvious
`
`variation or modification of the prior art may be considered non-obvious if one or
`
`more prior art references discourages or leads away from the line of inquiry
`
`disclosed in the reference(s). A reference does not “teach away” from an invention
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`simply because the reference suggests that another embodiment of the invention is
`
`better or preferred. My understanding of the doctrine of teaching away requires a
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`clear indication that the combination should not be attempted (e.g., because it
`
`would not work or explicit statements saying the combination should not be made).
`
`43.
`
`I understand that a person of ordinary skill is also a person of ordinary
`
`creativity.
`
`44.
`
`I further understand that in many fields, it may be that there is little
`
`discussion of obvious techniques or combination, and it often may be the case that
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`market demand, rather than scientific literature or knowledge, will drive design
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`trends. When there is such a design need or market pressure to solve a problem
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`and there are a finite number of identified, predictable solutions, a person of
`
`ordinary skill has good reason to pursue the known options within their technical
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`grasp. If this leads to the anticipated success, it is likely the product not of
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`innovation but of ordinary skill and common sense. In that instance the fact that a
`
`
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`combination was obvious to try might show that it was obvious. The fact that a
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`particular combination of prior art elements was “obvious to try” may indicate that
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`the combination was obvious even if no one attempted the combination. If the
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`combination was obvious to try (regardless of whether it was actually tried) or
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`leads to anticipated success, then it is likely the result of ordinary skill and
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`common sense rather than innovation.
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`III. THE 053 PATENT
`A. The Person Of Ordinary Skill in the Art
`I have reviewed the 053 Patent specification and its claims. Based on
`45.
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`my experience in the field and the information disclosed in the 053 Patent that I
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`discuss in this Declaration, I believe a person of ordinary skill in the art in the 053
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`Patent’s field of solar cell design or manufacture in 2008 (“Skilled Artisan”) would
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`have been someone with an advanced degree in electrical engineering, applied
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`physics, chemistry, or materials science, and at least two years of experience
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`designing, developing, or researching in the field. Alternatively, that person would
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`have had a bachelor’s degree in electrical engineering, applied physics, or
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`materials science, and at least three years of experience designing, developing, or
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`researching in the field.
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`46.
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`I was a Skilled Artisan before February 20, 2008 by this definition.
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`
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`14
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`Petitioner Canadian Solar Inc. - Ex. 1003, p. 14
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`

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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`053 Patent’s Effective Filing Date
`B.
`47. The 053 Patent, titled “Front Contact Solar Cell with Formed
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`Emitter,” was filed on June 13, 2012. EX1001. Based on the information on the
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`face of the 053 Patent, the 053 Patent is a divisional of, and claims priority to, U.S.
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`Patent No. 8,222,516 filed on February 20, 2008. I have been asked by CSI’s
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`counsel to assume that the 053 Patent’s effective filing date is February 20, 2008.
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`053 Patent’s Specification
`C.
`48. The 053 Patent discloses a solar cell as shown in Figure 1.
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`
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`49. Figure 1’s solar cell 100 includes an N-type silicon substrate 101.
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`EX1001, 2:35-38. According to the 053 Patent, a “backside junction” is formed by
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`the N-type substrate 101 and the P-type doped polysilicon emitter 108 formed at
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`
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`15
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`Petitioner Canadian Solar Inc. - Ex. 1003, p. 15
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`the solar cell’s backside. EX1001, 2:35-38, 1:53-55. Between the polysilicon
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`emitter 108 and the substrate 101 is a tunnel oxide layer 107, which “may comprise
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`silicon oxide thermally grown” on the substrate’s surface. EX1001, 2:64-3:6.
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`Backside metal contact 110 connects with the emitter 108 through contact holes
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`123 in the silicon dioxide layer 109. EX1001, 3:6-18.
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`50. At the front, the solar cell’s front side has a texture 113 and an
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`antireflective coating 103 made of silicon nitride. EX1001, 2:29-34, 3:19-30, 4:36-
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`41. Metal contact 102 at the front then connects with the substrate through holes in
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`the antireflective coating 103. EX1001, 2:57-63.
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`51. Figures 4A-4M illustrate the solar cell manufacturing process.
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`EX1001, 3:56-58. This summary focuses on steps relevant to the claim limitations
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`in Claims 9-20.
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`52. As shown in Fig. 4B, after the wafer/substrate is cleaned, tunnel
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`oxides 107/402 are thermally grown on the front and back substrate surfaces, and
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`polysilicon layers 108/401 are formed on the tunnel oxide layers by “CVD,” i.e.,
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`chemical vapor deposition. EX1001, 4:4-13. Polysilicon layer 108 becomes the
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`emitter in later steps. Id.
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`
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`16
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`Petitioner Canadian Solar Inc. - Ex. 1003, p. 16
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`
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`53. Subsequently, in preparation for doping the polysilicon layer 108, a p-
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`type dopant source 461 such as BSG (borosilicate glass) is formed is formed by
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`atmospheric pressure CVD (“APCVD”) on the polysilicon layer 108 with an
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`undoped silicon dioxide capping layer 462 as shown in Figure 4C. EX1001, 4:14-
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`27.
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`54. The front of the substrate then receives a texture 113 as seen in Figure
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`
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`4E. EX1001, 4:36-41.
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`
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`17
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`Petitioner Canadian Solar Inc. - Ex. 1003, p. 17
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`Declaration of Sanjay Banerjee Regarding U.S. Patent No. 8,878,053
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`
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`55. An N-type dopant source 412 is formed on the textured surface 113 as
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`shown in Figure 4F. EX1001, 4:42-59. The N-type dopant source 412 can
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`comprise “silicon dioxide doped with phosphorus.” Id., 4:51-52. Alternatively,
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`this step can be omitted, and N-type doping can occur later through introduction of
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`N-type dopant in the furnac