Trials@uspto.gov
`571-272-7822
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` Paper 68
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` Entered: February 11, 2014
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`NICHIA CORPORATION
`Petitioner
`
`v.
`
`EMCORE CORPORATION
`Patent Owner
`____________
`
`Case IPR2012-00005
`Patent 6,653,215
`____________
`
`
`
`Before KEVIN F. TURNER, STEPHEN C. SIU, and JONI Y. CHANG,
`Administrative Patent Judges.
`
`CHANG, Administrative Patent Judge
`
`
`
`
`
`FINAL WRITTEN DECISION
`35 U.S.C. § 318(a) and 37 C.F.R. § 42.73
`
`
`
`571-272-7822
`
`
`
`
`
`
`
`
`
`
`
` Paper 68
`
`
`
` Entered: February 11, 2014
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`NICHIA CORPORATION
`Petitioner
`
`v.
`
`EMCORE CORPORATION
`Patent Owner
`____________
`
`Case IPR2012-00005
`Patent 6,653,215
`____________
`
`
`
`Before KEVIN F. TURNER, STEPHEN C. SIU, and JONI Y. CHANG,
`Administrative Patent Judges.
`
`CHANG, Administrative Patent Judge
`
`
`
`
`
`FINAL WRITTEN DECISION
`35 U.S.C. § 318(a) and 37 C.F.R. § 42.73
`
`
`
`
`Case IPR2012-00005
`Patent 6,653,215
`
`I.
`INTRODUCTION
`Nichia Corporation (“Nichia”) filed a petition on September 16, 2012,
`requesting an inter partes review of claims 1-17 of U.S. Patent No.
`6,653,215 (“the ’215 patent”). Paper 2 (“Pet.”). The patent owner, Emcore
`Corporation (“Emcore”) did not file a preliminary response. Upon review of
`Nichia’s petition, the Board instituted this trial on February 12, 2013.
`During the trial, Emcore filed a patent owner response (Paper 24
`(“PO Resp.”)), and Nichia filed a reply to the patent owner response (Paper
`38 (“Pet. Reply”)). Emcore also filed a motion to amend claims (Paper 26);
`Nichia filed an opposition to Emcore’s motion to amend claims (Paper 40);
`and Emcore then filed a reply (Paper 43) to Nichia’s opposition. Oral
`hearing was held on November 6, 2013.1
`We have jurisdiction under 35 U.S.C. § 6(c). This final written
`decision is entered pursuant to 35 U.S.C. § 318(a). We hold that claims 1-17
`of the ’215 patent are unpatentable under 35 U.S.C. § 103(a). Emcore’s
`motion to amend claims is denied.
`
`A. Related Proceeding
`Nichia indicates that the ’215 patent is asserted in the litigation styled
`Emcore Corp. v. Nichia Corp., Case No. 2-12-cv-11758 (E.D. Mich). Pet. 1.
`
`
`
`
`1 A transcript of the oral hearing is included in the record as Paper 66.
`2
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`B. Real Party-in-Interest
`Emcore asserts that Nichia2 failed to identify all real parties-in-interest
`in the petition, as required by 35 U.S.C. § 312(a)(2). PO Resp. 1. In support
`of that assertion, Emcore alleges that Nichia represented to the district court,
`in a motion to stay, that both Nichia Corporation and Nichia America
`Corporation (“NAC”) filed the petition. Id. at 2 (citing Ex. 2017, 1).
`Emcore takes the position that the petition was “filed at the behest of both
`Nichia Corporation and NAC,” and that Nichia “is acting in the interest of
`NAC.” Id. at 3. Emcore submits that NAC is a subsidiary of Nichia, and as
`co-defendants in the district court litigation, both Nichia and NAC used the
`same expert witness and counsel, and asserted the same prior art and claim
`for a declaratory judgment. Id. at 3-4.
`Nichia disagrees and argues that a clerical error was made
`inadvertently in the motion to stay, and it has notified the district court of the
`clerical error. Pet. Reply 15. As support, Nichia has submitted a copy of the
`Notice Correcting Corporate Names (Ex. 1036) that was filed in the district
`court. Id. Nichia also asserts that NAC had no control over the decision to
`file a petition, drafting the petition, or the content of the petition. Id. at 14.
`Nichia further maintains that NAC did not fund the petition. Id.
`We are not persuaded by Emcore’s argument, as it is based on a
`clerical error made in a Nichia’s court filing, and speculations. Whether a
`party that is not named in an inter partes review is a “real party-in-interest”
`
`2 In the instant proceeding, the term “Nichia” refers to Nichia Corporation,
`and does not include Nichia America Corporation.
`3
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`is a “highly fact-dependent question,” taking into account various factors
`such as whether the non-party “exercised or could have exercised control
`over a party’s participation in a proceeding” and the degree to which a
`non-party funds directs and controls the proceeding. Office Patent Trial
`Practice Guide, 77 Fed. Reg. 48756, 48759-60 (Aug. 14, 2012).
`Upon review of the parties’ arguments and evidence, we determine
`that Emcore did not demonstrate adequately that Nichia failed to identify all
`real parties-in-interest. The petition identifies Nichia Corporation as the real
`party-in-interest. Pet. 1. Nichia’s motion to stay (Ex. 2017) and the Notice
`Correcting Corporate Names (Ex. 1036) reveal that: (1) the motion to stay
`used the shorthand “Nichia” to refer to both Nichia Corporation and NAC;
`(2) the motion to stay inadvertently stated that “Nichia filed a Petition for
`inter partes review . . .”; and (3) the motion to stay should have used
`“Nichia Corporation” rather than “Nichia.” Ex. 2017, 1-2; Ex. 1036, 2. The
`evidence before us clearly shows that the motion to stay filed in the district
`court contains a clerical error, especially in light of the fact that in the instant
`proceeding, we use the term “Nichia” to refer only to Nichia Corporation
`(see, e.g., Decision on Institution, Paper 13 at 2). Therefore, the evidence
`does not establish that NAC is a real party-in-interest to this proceeding.
`Moreover, the mere fact that Nichia and NAC, as co-defendants, shared the
`same counsel and expert witness, and had similar litigation strategy is not
`sufficient to prove that NAC exercised, or could have exercised, control over
`Nichia’s action in the instant proceeding. Nor does being a subsidiary of
`Nichia establish that NAC has the ability to control Nichia’s conduct in this
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`proceeding, in the absence of any evidence of contractual obligations of the
`parties. For the foregoing reasons, Emcore fails to demonstrate that Nichia
`did not identify all real parties-in-interest in the petition.
`
`C. The ’215 Patent
`The ’215 patent is directed to a method of forming a contact on an
`n-type III-V semiconductor by depositing four layers of metal and annealing
`the resulting stack. Ex. 1001, Abs. Figure 3 is a sectional view of a contact,
`and is reproduced below (with labels added, see Ex. 1001, 4:32-36):
`
`
`Figure 3 shows a contact formed in accordance with the claimed method.
`Claim 1, reproduced below, is the sole independent claim:
`A method of forming a contact on an n-type III-V
`semiconductor comprising the steps of:
`(a) depositing Al on the n-type III-V semiconductor to
`provide a base layer; then
`(b) depositing Ti on said base layer to provide a first
`barrier layer; then
`(c) depositing Pt on said first barrier layer to provide a
`second barrier layer; then
`(d) depositing Au on said second barrier layer to provide
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`a top layer, whereby said base layer, said first barrier layer, said
`second barrier layer, and said top layer form a stack on the
`n-type semiconductor; and then
`(e) annealing said n-type III-V semiconductor with said
`stack thereon.
`
`
`
`D. Prior Art Relied Upon
`Nichia relies upon the following prior art references:
`Fujimoto U.S. 6,242,761
`Jun. 5, 2001
`(Ex. 1007)
`Nakamura U.S. 5,563,422 Oct. 8, 1996 (Ex. 1013)
`Kawamura JP H06-37036
`Feb. 10, 1994 (Ex. 1014 & 1015)
`Sept. 25, 1998 (Ex. 1016 & 1017)3
`Kidoguchi JP10-256645
`JP H08-274372 Oct. 18, 1996 (Ex. 1018 & 1019)4
`Shibata
`
`Admitted Prior Art – the background section of ’215 patent (Ex. 1001,
`1:15-2:9) and the background section of provisional application 60/238,221
`(“the ’221 provisional application”) (Ex. 1004, 1-25).
`Murarka, et al., “Investigation of the Ti-Pt Diffusion Barrier for Gold
`Beam Leads on Aluminum,” 125 Iss.1 J. Electrochem. Soc. 1561978
`(Ex.1008).
`Vendenberg, et al., “An in situ x-ray study of gold/barrier-metal
`interactions with InGaAsP/InP layers,”55(10) J. Appl, Phys. 3676 (15 May
`1984) (Ex.1009).
`Lepselter, “Beam-Lead Technology,” 45, The Bell System Technical
`Journal 233 (1966) (Ex.1020).
`
`
`3 The exhibits provide the specified Japanese patent application and a
`certified English translation thereof, where we cite to the English translation.
`4 Ibid.
`5 All references to the page numbers of the ’221 provisional application refer
`to the original page numbers, and not the exhibit page numbers.
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`Terry, et al., “Metallization Systems for Silicon Integrated Circuits,”
`57, No. 9 Proc. IEEE 1580 (1969) (Ex. 1021).
`Hoff, et al., “Ohmic contacts to semiconducting diamond using a
`Ti/Pt/Au trilayer metallization scheme,” 5 (1996) Diamond and Related
`Materials 1450 (Ex. 1022).
`Durbha, et al., “Thermal Stability of Ohmic Contacts to n-InxGa1-xN,”
`395 Mat. Res. Soc. Symp. Proc. 825(1996) (Ex. 1023).
`
`
`E. Ground of Unpatentability
`The Board instituted the instant trial based on the ground that
`claims 1-17 of the ’215 patent are unpatentable under 35 U.S.C. § 103(a)
`over Kidoguchi, Nakamura, Fujimoto, Shibata, and the Admitted Prior Art.
`
`II. ANALYSIS
`
`A. Claim Construction
`We begin our analysis by determining the meaning of the claims.
`In an inter partes review, claim terms in an unexpired patent are given their
`broadest reasonable construction in light of the specification of the patent in
`which they appear. 37 C.F.R. § 42.100(b). Under the broadest reasonable
`construction standard, claim terms are given their ordinary and customary
`meaning as would be understood by one of ordinary skill in the art in the
`context of the entire disclosure. In re Translogic Tech. Inc., 504 F.3d 1249,
`1257 (Fed. Cir. 2007). An inventor may rebut that presumption by
`providing a definition of the term in the specification with reasonable clarity,
`deliberateness, and precision. In re Paulsen, 30 F.3d 1475, 1480 (Fed. Cir.
`1994). In absence of such a definition, limitations are not to be read from
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`the specification into the claims. In re Van Geuns, 988 F.2d 1181, 1184
`(Fed. Cir. 1993).
`
`1. “III-V semiconductor” (claim 1); “n-type” as used with
`semiconductor (claim 1); “pure nitride semiconductor” or “pure
`nitride compound semiconductor” (claim 12)
`
`In its petition, Nichia notes that the ’215 patent expressly defines
`these semiconductor claim terms in the specification. Pet. 10-11 (citing
`Ex. 1001, 5:5-8; 5:14-17; 5:5-12). Upon review of the cited portions of the
`specification, we observe that the definitions are set forth in the specification
`with reasonable clarity, deliberateness, and precision. Therefore, we adopt
`the definitions as the broadest reasonable constructions for the
`semiconductor claim terms set forth in the table below.
`
`Terms
`
`III-V semiconductor
`
`“n-type” as used
`with semiconductor
`
`Pure nitride
`semiconductor or
`pure nitride
`compound
`semiconductor
`
`
`Definitions
`A semiconductor according to the stoichiometric
`formula Ala Inb Gac Nx Asy Pz where (a+b+c) is about
`1 and (x+y+z) is also about 1. Ex. 1001, 5:5-8.
`A semiconductor having n-type conductivity, i.e., a
`semiconductor in which electrons are the majority
`carriers. Id. at 5:14-17.
`
`A nitride semiconductor in which x [in the
`stoichiometric formula Ala Inb Gac Nx Asy Pz ] is
`about 1.0. Id. at 5:10-12.
`
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`2. “annealing” (claim 1)
`
`The claim term “annealing” is recited in claim 1 in the following
`limitation: “annealing said n-type III-V semiconductor with said stack
`thereon.”
`Nichia submits that the claim term “annealing” means “heating to
`temperatures between 400-900 ºC and for a duration sufficient to cause a
`desired change in the properties of the contact stack.” Pet. 14 (internal
`quotation marks omitted). We observe that Nichia’s construction would
`import improperly a limitation—“temperatures between 400-900 ºC”—from
`the specification into the claims. Van Geuns, 988 F.2d at 1184. Moreover,
`Nichia’s proposed construction is inconsistent with the specification and the
`ordinary and customary meaning of the term. For instance, in the
`background section of the ’215 patent discussing prior art methods of
`forming a contact, there is no indication that the annealing step includes such
`a temperature-range requirement. Ex. 1001, 1:59-2:10. Therefore, we do
`not adopt Nichia’s proposed construction as the broadest reasonable
`interpretation for the claim term “annealing.”
`Emcore urges that the claim term “annealing” should be construed as
`“heating the semiconductor sufficiently to form a contact with low
`resistance.” PO Resp. 24. In support of its proposed construction, Emcore
`maintains that “the specification does not require simply any change to
`occur,” but “it requires a specific and beneficial change, i.e., the resulting
`contact should have a low resistance and reliable bonding.” PO Resp. 25
`(citing Ex. 1001, 4:26-27) (emphasis added). Emcore further argues that
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`“the method disclosed by the ’215 patent emphasizes that it discloses a
`particular method where annealing a contact with an Al base layer results in
`a contact with low resistance and reliable boding.” PO Resp. 26 (citing
`Ex. 1011, 4-5). According to Emcore, those statements “distinguishing the
`claimed invention from the prior art go to the heart of the full understanding
`of what the inventors actually invented.” Id. (internal citations omitted).
`We do not agree with Emcore that its proposed construction is the
`broadest reasonable interpretation of the claim term “annealing,” as it would
`import improperly a limitation—“sufficiently to form a contact with low
`resistance”—from the specification into the claims. Gemstar-TV Guide
`Int’l, Inc. v. ITC, 383 F.3d 1352, 1366 (Fed. Cir. 2004) (rejecting expressly
`the contention that claims must be construed as limited to an embodiment
`disclosed in the patent).
`We also are not persuaded by Emcore’s arguments. They fail to
`recognize that it is “a bedrock principle of patent law that the claims of a
`patent define the invention to which the patentee is entitled the right to
`exclude.” Phillips v. AWH Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005)
`(citations and quotation marks omitted); see also Markman v. Westview
`Instruments, Inc., 52 F.3d 967, 980 (Fed. Cir. 1995) (en banc) (“The written
`description part of the specification itself does not delimit the right to
`exclude. That is the function and purpose of claims.”).
`Emcore has not alleged that the inventors of the ’215 patent acted as
`their own lexicographer and provided a special definition in the specification
`for the claim term “annealing” that is different from its recognized meaning
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`to one with ordinary skill in the art. The claim language used by Emcore is
`broad. There is no requirement as to the resistivity of the contact or a
`specific and beneficial change, as urged by Emcore. One with ordinary skill
`in the art may use “annealing” to form a contact that does not have a low
`resistance contact or to form other semiconductor structures.
`In support of Emcore’s position, Dr. Mark S. Goorsky testifies that
`Emcore’s proposed construction is correct, because “[w]hen the ’215 patent
`uses the term ‘annealing,’ it means specifically a ‘contact anneal.’”
`Ex. 2001 ¶ 61 (citing Ex. 1002 ¶ 31). However, Dr. Goorsky relies on
`Nichia’s expert testimony that does not support Emcore’s proposed
`construction, as it does not discuss Emcore’s proposed construction, nor
`contact resistivity. Ex. 1002 ¶ 31. Neither expert’s testimony (Ex. 2001
`¶ 61; Ex. 1002 ¶ 31) explains sufficiently why the term “annealing” should
`be limited specifically to “heating the semiconductor sufficiently to form a
`contact with low resistance.” As Emcore notes (PO Resp. 25-26), the
`contacts disclosed in the prior art, including those that are formed with
`annealing, may or may not produce a low contact resistance. Therefore,
`Emcore’s proposed construction would be inconsistent with the claim term’s
`ordinary and customary meaning as would be understood by one of ordinary
`skill in the art.
`Moreover, Emcore, in its patent owner response, does not explain the
`meaning of the term “low resistance.” PO Resp. 24-26. Upon inquiry at the
`final oral hearing, counsel of Emcore stated that he agrees with the definition
`proffered by Nichia’s expert, Dr. E. Fred Schubert. Trial Tr. (Paper 66),
`
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`34:17-23. Dr. Schubert testifies:
` Ωcm2
`In 1999-2000, a contact resistance of 10-5
` would simply
`have reflected the approximate dividing line between a
`desirable contact and an undesirable contact. Higher than 10-5
`
`Ωcm2
` would have been considered a poor contact resistance,
`while below 10-5
` Ωcm2
` would have been considered a good
`contact resistance (for example, Schroder, “Semiconductor
`Material and Device Characterization,” Ex. 1025, p. 125 stated
`in 1990 that high-quality contacts were on the order of 10-6
`Ωcm2). The 1997 review article by Baca, et al. surveyed
`contacts for n-type III-V semiconductors, and found none that
`exceeded 10-5
` Ωcm2, with most contacts substantially below that
`value (Baca, et al., Ex. 1024, p. 604, Table 1).
`Ex. 1002 ¶ 55 (emphasis added).
`Although that definition of “low resistance” is also consistent with the
`specification of the ’215 patent (Ex. 1001, 4:43-46), Emcore’s proposed
`construction would render the limitation recited in claim 15—“a contact
`resistance of less than about 10-5 ohm-cm2”—insignificant, if not wholly
`superfluous. Emcore’s proposed construction also would render claim 15,
`that depends from claim 1, an improper dependent claim under 35 U.S.C.
`§ 112, ¶ 4. Emcore does not explain adequately as to why the term
`“annealing” recited in independent claim 1 should be construed to require a
`limitation recited in a dependent claim 15. Phillips, 415 F.3d at 1314-15
`(stating “the presence of a dependent claim that adds a particular limitation
`gives rise to a presumption that the limitation in question is not present in
`the independent claim.”); see also Curtiss-Wright Flow Control Corp. v.
`Velan, Inc., 438 F.3d 1374, 1380 (Fed. Cir. 2006) (“In the most specific
`sense, ‘claim differentiation’ refers to the presumption that an independent
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`claim should not be construed as requiring a limitation added by a dependent
`claim.”).
`In determining the ordinary and customary meaning of the claim term,
`it is appropriate to consult a general dictionary definition of the word for
`guidance. Comaper Corp. v. Antec, Inc., 596 F.3d 1343, 1348 (Fed. Cir.
`2010). The ordinary meaning of the word “anneal” includes “to heat (glass,
`earthenware, metals, etc.) to remove or prevent internal stress.”6
`Consistent with the usage in the prior art and in the specification of
`the ’215 patent, we construe “annealing” as heating the semiconductor
`structure sufficiently to cause a change in some property of the
`semiconductor structure. See e.g., Ex. 1001, 1:59-61 (“When the electrode
`is annealed it becomes transparent so that light emitted within the [light-
`emitting diodes (“LED”)] can pass out of the device through the
`electrode.”); 2:12-15 (“[W]here a gold layer is provided on a contact
`containing titanium and aluminum, the gold layer can change during
`annealing.”); 4:47-49 (“Where the first barrier layer includes Ti, there can be
`some diffusion of Ti into the Al-containing base layer during annealing.”).
`
`3. “base layer” (claim 1)
`Claim 1 recites “depositing Al on the n-type III-V semiconductor to
`provide a base layer.” Emcore submits that the claim term “base layer”
`should be construed as “[t]he first-deposited metal layer used to form a
`low-resistance, ohmic contact to the semiconductor.” PO Resp. 26-27.
`
`6 RANDOM HOUSE WEBSTER’S COLLEGE DICTIONARY (2nd ed. 1999).
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`We disagree that Emcore’s proposed construction is the broadest
`reasonable interpretation of the claim term “base layer,” as it would import
`improperly a limitation—“a low-resistance, ohmic contact to the
`semiconductor”—from the specification into the claims.
`In support of its position, Emcore cites to Nichia’s expert testimony
`(Ex. 1002 ¶ 20), and the testimony of its expert (Ex. 2001 ¶¶ 62-63), who
`also cites to Nichia’s expert testimony for support of his opinion. However,
`Nichia’s expert testimony does not support Emcore’s proposed construction
`or the opinion of Emcore’s expert. As Nichia explains, the portion of
`Nichia’s expert testimony relied upon by Emcore and its expert does not
`discuss the term “base layer,” but rather explains “the function of an ohmic
`contact layer.” Pet. Reply 1; Ex. 1002 ¶ 20.
`Further, the background section of the ’215 patent (Admitted Prior
`Art) provides the following:
`In most semiconductor devices, the contacts should
`exhibit “ohmic” characteristics. That is, the electrical voltage
`loss at the boundary between the contact and the semiconductor
`material should be substantially proportional to the current, and
`should be independent of the direction of current flow, so that
`the contact acts as a conventional electrical resistor. Also, the
`contact desirably has low resistance. For example, a light
`emitting diode with low resistance ohmic contacts can convert
`electrical power into light more efficiently than a similar diode
`with high resistance contacts. The contacts typically are
`connected to metallic leads as, for example, by wire-bonding
`processes. The contacts should include metals which are
`[compatible] with these processes.
`Ex. 1001, 1:33-46 (emphases added).
`
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`As noted in the specification, the goal of forming a low-resistance,
`ohmic contact is desirable, but not all semiconductor devices have such
`desirable characteristics. See also Ex. 1001, 2:11-20 (“Despite these and
`other efforts in the art, still further improvements would be desirable.”).
`In light of the specification, we construe the term “base layer” broadly, but
`reasonably, as “the first-deposited metal layer used to form a contact to the
`semiconductor.”
`
`4. “barrier layer” (claim 1)
`Claim 1 recites “depositing Ti on said base layer to provide a first
`barrier layer” and “depositing Pt on said first barrier layer to provide a
`second barrier layer.” Emcore asserts that the broadest reasonable
`interpretation of the claim term “barrier layer” is “[a] layer provided to
`prevent undesirable reactions between the top layer and the base layer.”
`PO Resp. 27 (citing Ex. 1001, 2:53-65; Ex. 1002 ¶ 25).
`Upon review of the specification, we observe that Emcore’s proposed
`construction is consistent with the specification and the understanding of one
`with ordinary skill in the art. Ex. 1001, 2:53-65 (“[I]t is believed that the
`barrier layers such as Ti and Pt layers above the Al-containing base layer
`prevent undesirable reactions between Al and the metal of the top layers Au
`during annealing and/or during service.”); Ex. 1002 ¶ 25 (“Barrier layers
`have the purpose of preventing the diffusion, intermixing, undesirable forms
`of alloying, and chemical reaction between the first and last deposited
`metal.”). However, the claims require more than one barrier layer.
`
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`Therefore, in the light of the claims and specification, we construe the
`claim term “barrier layer” broadly, but reasonably, as “a layer provided in
`between two layers to prevent undesirable reactions between the two layers.”
`
`B. Obviousness Over Kidoguchi, Nakamura, Fujimoto,
`Shibata, and the Admitted Prior Art
`Nichia asserts that claims 1-17 are unpatentable under 35 U.S.C.
`§ 103(a) over Kidoguchi, Nakamura, Fujimoto, Shibata, and the Admitted
`Prior Art. Pet. 39. In support of its asserted ground of unpatentability,
`Nichia provides explanations as to how each limitation is met by the
`combination of cited prior art references and rationales for combining the
`prior art references. Pet. 34-47. Nichia also relies upon a declaration of
`Dr. Schubert. Ex. 1002.
`Upon review of Nichia’s contentions and supporting evidence, as well
`as Emcore’s patent owner response and supporting evidence, we determine
`that Nichia has demonstrated, by a preponderance of the evidence, that
`claims 1-17 of the ’215 patent are unpatentable over Kidoguchi, Nakamura,
`Fujimoto, Shibata, and the Admitted Prior Art.
`
`1. Principles of Law
`
`In an obviousness analysis, it is not necessary to find precise teachings
`in the prior art directed to the specific subject matter claimed because
`inferences and creative steps that a person of ordinary skill in the art would
`employ can be taken into account. KSR Int’l Co. v. Teleflex Inc., 550 U.S.
`398, 418 (2007). A basis to combine teachings need not be stated expressly
`
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`Patennt 6,653,2
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`
`in anny prior artt reference. In re Ka
`hn, 441 F.
`
`
`
`
`3d 977, 9887-88 (Fedd. Cir.
`
`
`
`
`
`
`20066). There nneed only bbe an articuulated reassoning withh rational
`
`
`undeerpinnings to supportt a motivation to commbine teachhings. Id. aat 988.
`
`
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`The level of orrdinary skilll in the artt is reflecteed by the pprior art of f record.
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`See OOkajima v.. Bourdeauu, 261 F.3dd 1350, 13555 (Fed. CCir. 2001);
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`In ree GPAC Inc., 57 F.3dd 1573, 15779 (Fed. CCir. 1995); IIn re Oelriich,
`F.2d 86, 9
`579
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`1 (CCPA 11978).
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`22. Prior Arrt
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`a. Kidogguchi
`light
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`Kidogucchi describes a methood of formiing a semicconductor
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`emittting devicee. Ex. 10117 ¶ 01. Fiigure 1 of KKidoguchii is reproduuced beloww:
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`laser deevice formeed in accorrdance withh Kidogucchi’s inventtion.
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`Figgure 1 of KKidoguchi ddepicts the structure oof a GaN-bbased semiiconductorr
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`In particcular, Kidooguchi disccloses formming a GaNN-based
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`semiiconductorr laser deviice using GGaN. Ex. 11017 ¶ 16.
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` Kidoguchhi also
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`Patent 6,653,215
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`discloses forming an n-GaN contact having an electrode that is formed using
`Ti, Al, and Au, with Au as the outermost layer (i.e., the top layer). Id. at
`¶ 31. Kidoguchi acknowledges the problem of high contact resistivity and
`loss of reliability when Au diffuses into the n-type GaN contact layer. Id.
`Kidoguchi teaches a method of suppressing the Au diffusion to decrease the
`contact resistance. Id. at ¶ 32. Kidoguchi’s method includes the steps of
`using Al as the n-GaN contact metal (i.e., the base layer), inserting a Pt layer
`(i.e., a barrier layer) under the Au layer to suppress the diffusion of Au, and
`inserting a Ti layer (i.e., a barrier layer) to suppress the diffusion of Pt—to
`form an Al/Ti/Pt/Au n-side electrode on a GaN semiconductor. Id. at ¶¶ 32-
`33, Fig. 14.
`
`b. Fujimoto
`Fujimoto discloses a method of forming GaN semiconductor light
`emitting devices. Ex. 1007, 1:7-12. Figure 6 of Fujimoto is reproduced
`below.
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`Figure 6 of Fujimoto illustrates a light emitting device formed
`according to an embodiment of Fujimoto.
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`Patent 6,653,215
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`As shown in Figure 6 of Fujimoto, semiconductor device 600 has n-
`side electrode 640 on the n-type GaN semiconductor. Fujimoto discloses
`forming the electrode with an Al/Pt/Au multi-layered structure and
`annealing the electrode on the GaN semiconductor at a temperature around
`400 ºC. Id. at 16:41-46. Fujimoto further teaches interposing one or more
`Ti layers to the three-layered electrode. Id. at 20:13-16.
`
`c. Shibata
`Shibata discloses a method of forming a semiconductor light emitting
`device. Ex. 1019, Abs. Figure 1 of Shibata is reproduced below (emphasis
`added).
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`Figure 1 of Shibata shows a cross section of a light emitting device.
`As illustrated in Figure 1 of Shibata, light emitting semiconductor
`device 10 has electrode 8 comprised of an Al/Ti/Au structure formed on
`n-type GaN semiconductor 3. Id. at ¶¶ 11-13, 26. Shibata also describes
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`annealing the structure at 600 ºC for one minute to form a device with a
`contact resistance of 10-5 ohm-cm2 or less. Id. at ¶ 27. According to
`Shibata, the resulting device was observed to have sufficient bonding
`strength and good ohmic contact. Id. Shibata also notes other advantages of
`its invention—extended life of the light emitting device and improved
`stability of emission. Id.
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`d. Nakamura
`Nakamura discloses a method of forming a GaN semiconductor
`device. Ex. 1013, 1:7-19; 4:43-47. Nakamura notes that, at the time of its
`invention in the 1994 timeframe, it was known in the art to use Al as a
`material for an n-electrode of a GaN semiconductor light emitting device.
`Id. at 2:17-19. Nakamura also acknowledges that Al could degrade by an
`annealing. Id. at 2:21-24. Nonetheless, Nakamura describes a method that
`would overcome that problem by forming a Ti/Al/Au electrode and
`annealing the structure to establish an ohmic contact to an n-type GaN
`semiconductor. Id. at 2:46-51; 3:19-26; 11:3-14. Nakamura states that
`annealing at a temperature of 400 ºC or more, for 0.01 to 30 minutes is
`preferable. Id. at 11:15-18.
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`e. Admitted Prior Art
`The Admitted Prior Art includes the background section of the ’221
`provisional application (Ex. 1004, 1-2) and the background section of the
`’215 patent (Ex. 1001, 1:15-2:9). In particular, the background section of
`the ’215 patent states that, in most semiconductor devices, the contacts
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`Patent 6,653,215
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`should exhibit low “ohmic” characteristics and low contact resistance.
`Ex. 1001, 1:33-40. It also notes that a light emitting diode with
`low-resistance ohmic contacts can convert electrical power into light more
`efficiently than a similar diode with high-resistance contacts. Id. at 1:40-43.
`According to the background section of the ’215 patent, it was known at the
`time of the invention to form contacts for n-type GaN by annealing a Ti and
`Al structure. Id. at 1:64-2:4. The background section of the ’221
`provisional application states that “[t]ypical low work function metal/metal
`stack with yield low contact resistance to n-GaN on annealing is Al, Ti/Al.”
`Ex. 1004, 1 (emphasis added). It also recognizes that, for the purposes of
`achieving low contact resistance, “most metallization schemes to n-GaN use
`Ti, Ti/Al or Al followed by Ni/Au,” and “[a]nnealing of the metallization is
`carried out at temperatures between 400-900 C for minimum contact
`resistance.” Id. at 2 (emphasis added).
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`3. Claims 1 and 11-14
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`In its patent owner response, Emcore counters that Nichia fails to
`meet its burden of demonstrating claim 1 of the ’215 patent is unpatentable
`over the combination of Kidoguchi, Nakamura, Fujimoto, Shibata, and the
`Admitted Prior Art. PO Resp. 32. In particular, Emcore argues that the
`primary reference Kidoguchi does not describe an Al base layer and barrier
`layers, as recited in claim 1. Emcore further asserts that the cited prior art
`references teach away from the claimed invention.
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`a. Forming Al/Ti/Pt/Au electrode on an n-type GaN semiconductor
`Claim 1 requires forming an Al/Ti/Pt/Au structure on an n-type III-V
`semiconductor. Claims 11 and 12 directly depend from claim 1. Claim 11
`further recites “wherein said n-type semiconductor is a nitride compound
`semiconductor.” Claim 12 further recites “wherein said n-type
`semiconductor is a pure nitride compound semiconductor.” Claim 13
`depends from claim 11 and further recites “wherein said n-type
`semiconductor is a gallium nitride based semiconductor.” Claim 14 depends
`from claim 11 and further recites “wherein said n-type semiconductor is
`GaN.” We determine that an n-type GaN semiconductor meets the “n-type
`semiconductor” limitations recited in claims 1 and 11-14.
`According to Nichia, Kidoguchi describes an Al/Ti/Pt/Au electrode
`formed on an n-type GaN semiconductor, as required by claims 1 and 11-14.
`Pet. 35. Indeed, Figure 14(a) of Kidoguchi shows a contact formed on an
`n-type GaN semiconductor with layers Mo/Ti/Pt/Au. Kidoguchi discloses
`that Al can be substituted for Mo because Al is used conventionally for the
`n-electrode. Ex. 1017 ¶¶ 31-33.
`Emcore, however, argues that Kidoguchi does
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