Ex Parte WOO et alDownload PDFPatent Trial and Appeal BoardMay 31, 201812950912 (P.T.A.B. May. 31, 2018) Copy Citation UNITED STA TES p A TENT AND TRADEMARK OFFICE APPLICATION NO. FILING DATE 12/950,912 11/19/2010 124834 7590 06/04/2018 MH2 Technology Law Group (w/Boeing) TIMOTHY M. HSIEH 1951 Kidwell Drive Suite 310 Tysons Corner, VA 22182 FIRST NAMED INVENTOR RobynL. WOO UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www .uspto.gov ATTORNEY DOCKET NO. CONFIRMATION NO. 10-0389-US-NP/0192.0153 8687 EXAMINER DANICIC, CHRISTOPHER ART UNIT PAPER NUMBER 1758 NOTIFICATION DATE DELIVERY MODE 06/04/2018 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): doreen@mh2law.com docketing@rnh2law.com patentadmin@boeing.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte ROBYN L. WOO, DANIEL C. LAW, and JOSEPH CHARLES BOISVERT Appeal2017-007884 Application 12/950,912 Technology Center 1700 Before MICHAEL P. COLAIANNI, GEORGE C. BEST, and N. WHITNEY WILSON, Administrative Patent Judges. COLAIANNI, Administrative Patent Judge. DECISION ON APPEAL Appellants 1 appeal under 35 U.S.C. § 134 the final rejections of claims 1, 2, 4, 7-10, 14--18, and 24. Claims 19-23, the other claims pending in this application, stand withdrawn from consideration by the Examiner. We have jurisdiction over the appeal pursuant to 35 U.S.C. § 6(b ). We AFFIRM. 1 Appellants identify the real party in interest as The Boeing Company (Br. 3). Appeal2017-007884 Application 12/950,912 Appellants' invention is directed to photovoltaic cells and, more specifically, to solar cells of InP lattice constant having high bandgap, type- II tunnel junctions (Spec. ,r 2). Claim 1 is illustrative: 1. A tunnel junction, comprising: a p-doped tunnel layer comprising AlGainAs; and a n-doped tunnel layer in contact with the p-doped tunnel layer; wherein the tunnel junction has an InP lattice constant; wherein the tunnel junction is optically transparent, forming a heterojunction; wherein the p-doped tunnel layer has a bandgap of greater than 1.25 e V and the n-doped tunnel layer has a bandgap of greater than 1.35 eV; and wherein the n-doped tunnel layer is also a window layer for a subcell underneath the tunnel junction. (Br. 12 (Claims App.) ( emphasis added)). Appellants appeal the following rejections: 1. Claims 1, 2, 4, 7-10, and 24 are rejected under 35 U.S.C. § I03(a) as unpatentable over Gu et al. ("High-efficiency InP Based Four- junction Solar Cells," Annual Meeting of the IEEE Lasers and Electro- Optics Society, (2) 927-28 (2003), "Gu") in view of Chang et al. (US 2004/0051113 Al, published Mar. 18, 2004, "Chang") as evidenced by, or in further view of Olson (US 4,667,059, issued May 19, 1987, "Olson"). 2. Claims 8-10 and 14--18 are rejected under 35 U.S.C. § I03(a) as unpatentable over Gu in view of Chang, Olson, and further in view of Wanlass (US 5,019,177, issued May 28, 1991, "Wanlass"). 2 Appeal2017-007884 Application 12/950,912 Appellants' arguments focus solely on independent claims 1, 8, and 24 (Br. 4--10). We select claim 1 as representative. 37 C.F.R. § 4I.37(c)(l)(iv). Accordingly, claims 2, 4, 7-10, 14--18, and 24 will stand or fall with our analysis of claim 1. FINDINGS OF FACT & ANALYSIS Gu's Figure 4, which illustrates the structure of a tunnel junction, is reproduced below. 3el8 150mn ·o."-AHnAs lel9 100nm le19 ·· ilOOnm n,.lnP Buffer laver 2e 18 150nm - ·· . n-lnP Substrate Rear Contact · Gu' s Figure 4 illustrates features of a tunnel junction structure, including a p-doped AlinAs layer having a dopant concentration 1 x 1019/cm3 and an n-doped InP layer having a dopant concentration 1 x 1019/cm3• With respect to the claimed n-type junction layer, the Examiner finds that Gu's InP layer "having a band gap of 1.35 eV ... and a dopant concentration of 1019 / cm3 would act as a window layer to the layers below it, passing non-absorbed light to the lower layers and being capable of passivating (reducing minority carrier recombination)." (Ans. 6) (emphasis added). Appellants argue, inter alia, that the ordinary skilled artisan would not have found it obvious to modify Gu because increasing the doping level of a window layer would have introduced crystal defects therein (Br. 5). 3 Appeal2017-007884 Application 12/950,912 According to Appellants, such "crystal defects reduce the ability of the window layer to prevent minority carrier recombination," thereby reducing the window layer's ability to function. Id. (citing Spec. ,r 33). Thus, according to Appellants, "a person of ordinary skill in the art would have expected that such a structure would result in decreased device performance" (Br. 5-6, emphasis in original). Appellants' arguments are not persuasive. First, there is no dispute that Gu discloses the requisite doping concentration of 1 x 1019/cm3 to 1 x 1020/cm3 for both the p-doped and n- doped tunnel layers (see generally Br. 4--10; Spec. ,r 41, claim 4; Ans. 11 (citing Gu Fig. 4)). Accordingly, Appellants have not identified reversible error in the Examiner's findings with respect to the dopant concentration. Thus, we agree with the Examiner that "no modification is made to the Gu tunnel junction to arrive at the claimed doping levef' (Ans. 12 ( emphasis in original)). Second, Appellants have not adequately explained why Gu's tunnel junction layer would have suffered from decreased device performance because the Specification describes an n-doped tunnel junction layer that is substantially similar to Gu's. For example, both Gu and the Specification describe an n-doped tunnel junction layer comprised of InP and having a doping concentration of 1 x 1019/cm3 (compare Gu Fig. 4 with Spec. ,r 41, claim 4, Fig. 2). As the Examiner found, Gu's tunnel junction layer must transmit light to the underlying subcells in order for these subcells to function (Ans. 12; see Gu Fig. 1). Thus, we find the Examiner's arguments persuasive that Gu's tunnel junction layer would have satisfied Appellants' criteria for a desired window layer function (Ans. 6, 12; see also Spec. ,r 33 4 Appeal2017-007884 Application 12/950,912 ( explaining that "the optical properties of the window material must be such that as much light as possible is transmitted to the first photoactive subcell ... , and any additional photoactive subcell layers that may be disposed underneath thereof ... , where the photogenerated charge carriers can be collected more efficiently.")). On this record, we find that the preponderance of the evidence supports the finding that Gu describes or teaches an n-doped tunnel layer that is also a window layer for a subcell underneath the tunnel junction, as required in claim 1. The Examiner further finds that Gu's tunnel junction structure teaches or suggests all of the limitations recited in claim 1, with the exception that Gu is silent regarding the p-doped tunnel layer comprising AlGainAs and the requisite band gap thereof (Ans. 3--4). The Examiner relies upon Chang's disclosure, which teaches a solar cell having a tunnel junction comprising AlinGaAs. Id. at 4. The Examiner determines that because "AlinGaAs and AlinAs are known tunnel junction materials in the solar cell art" and that both "provide electrical properties [including the requisite band gap] to function in solar cell tunnel junctions for a photovoltaic cell," each compound "would have been found obvious variants by one of ordinary skill in the art at the time of the invention." Id. at 4; see also id. at 5. Appellants argue, inter alia, "that a person of ordinary skill in the art would not have had a reasonable expectation of success or otherwise been motivated to modify Gu with Chang and Olson" (Br. 9). Appellants further argue that the Examiner's proposed modification would have resulted in a tunnel junction with decreased performance. Id. According to Appellants, the critical issue in the instant appeal is whether a person of ordinary skill in 5 Appeal2017-007884 Application 12/950,912 the art would have found it obvious to modify Gu as proposed by the Examiner to arrive at the claimed tunnel junction structure. Id. at 7. We are unpersuaded by these arguments and agree with the Examiner's determination of obviousness (Ans. 3---6, 13-14). First, the Examiner's proposed modification would have modified the p-doped tunnel junction layer only--Gu' s n-doped tunnel junction layer would have been left unmodified (Ans. 13). For the reasons set forth above, Appellants' arguments are not persuasive that Gu's n-doped tunnel junction layer would have suffered from decreased device performance. Moreover, Appellants have not provided any persuasive technical reasoning or evidence to rebut the Examiner's finding that the proposed "change in composition from AlinAs to AlGainAs for the p-type layer would not [have] change[ d] the window properties of the Gun-type InP tunnel junction layer with respect to the underlying subcell." Id. Second, the Examiner's proposed modification of Gu, in view of Chang, as evidenced by or in further view of Olson, provides the same p- doped and n-doped tunnel layer compositions, each with the requisite bandgaps, and arranged as the presently claimed tunnel junction. See id. As found by the Examiner, Chang's p-doped tunnel junction layer, comprising AlGainAs, is proven to work well in such a layer for use in multi-junction solar cells and may be lattice matched to an n-type InP tunnel junction layer. Id. at 13. Thus, modifying Gu' s p-doped tunnel junction layer to incorporate the known AlGainAs would have achieved the desired solar cell structure with predictable results and a reasonable expectation of success. See KSR Int'! Co. v. Teleflex, Inc., 550 U.S. 398,416 (2007) ("The combination of familiar elements according to known methods is likely to be obvious when 6 Appeal2017-007884 Application 12/950,912 it does no more than yield predictable results."); id. at 417 ("[I]f a technique has been used to improve one device, and a person of ordinary skill in the art would recognize that it would improve similar devices in the same way, using the technique is obvious unless its actual application is beyond his or her skill."). Appellants have not adequately explained why one skilled in the art, using no more than ordinary creativity, would not have been capable of adapting Chang's p-doped tunnel junction layer, comprising AlGainAs, as a p-doped tunnel junction layer in Gu's tunnel junction layer, while satisfying Chang's requirement for a functional solar cell. See In re Sovish, 769 F.2d 738, 743 (Fed. Cir. 1985) (skill is presumed on the part of one of ordinary skill in the art); In re Bozek, 416 F.2d 1385, 1390 (CCPA 1969). Appellants further argue that the Examiner's reliance upon Wanlass fails to cure the deficiencies of Gu, Chang, and Olson (Br. 10). We, however, agree with the Examiner that Appellants have not identified any such deficiencies. On this record, we affirm the Examiner's Rejections I and II under § 103(a) of claims 1, 2, 4, 7-10, 14--18, and 24. 37 C.F.R. § 4I.37(c)(l)(iv). DECISION The Examiner's decision is affirmed. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a)(l )(iv). ORDER AFFIRMED 7 Copy with citationCopy as parenthetical citation