DETAILED ACTION
Email Communication
Applicant is encouraged to authorize the Examiner to communicate via email by filing form PTO/SB/439 either via USPS, Central Fax, or EFS-Web. See MPEP 502.01, 502, 502.03.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114 was filed in this application after a decision by the Patent Trial and Appeal Board, but before the filing of a Notice of Appeal to the Court of Appeals for the Federal Circuit or the commencement of a civil action. Since this application is eligible for continued examination under 37 CFR 1.114 and the fee set forth in 37 CFR 1.17(e) has been timely paid, the appeal has been withdrawn pursuant to 37 CFR 1.114 and prosecution in this application has been reopened pursuant to 37 CFR 1.114. Applicant’s submission filed on 01/13/2026 has been entered.
Response to Amendment
Applicant’s argument of 01/13/2026 does not place the Application in condition for allowance.
Claims 1-5, 7-8 and 10-21 are currently pending.
Status of the Rejections
In response to Applicant’s amendment to claim 1, All rejections from the previous Office Action mailed are withdrawn. However, upon further consideration, a new ground of rejection is presented below.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-5, 7-8, 10-15 and 17-21 are rejected under 35 U.S.C. 103 as being unpatentable over King et al. (US 2014/0261611 A1) in view of Suarez et al. (US 2017/0110613 A1).
Regarding claim 1, King discloses a monolithic metamorphic multi-junction solar cell (MJ cell 10) ([0111], figures 33-40) comprising:
a first III-V subcell (cell 1, figure 35) comprising a first emitter layer and a first base layer (inherent or implicit, see also fig. 33 that shows each subcell comprises a base and an emitter);
a second III-V subcell (cell 2, fig. 35) comprising a second emitter layer and a second base layer (inherent or implicit, see also fig. 33 that shows each subcell comprises a base and an emitter);
a third III-V subcell (cell 3, fig. 35) comprising a third emitter layer and a third base layer (inherent or implicit, see also fig. 33 that shows each subcell comprises a base and an emitter);
a fourth Ge subcell (cell 4, fig. 35) comprising a fourth emitter layer and a fourth base layer (inherent or implicit, see also fig. 33 that shows each subcell comprises a base and an emitter),
the first, second, third, and fourth subcells being stacked in the indicated order with the first subcell forming a topmost subcell (see fig. 35 for the claimed configuration);
a first metamorphic buffer (52, fig. 33) formed between the third subcell and the fourth subcell (see fig. 33 and 35);
wherein the first, second, third and fourth emitter layers are n-doped, and the first, second, third, fourth base layers are p-doped (see figure 33 that shows each cell has p-type base and n-type emitter),
wherein a thickness of the first emitter layer is less than a thickness of the first base layer ([0029]), a thickness of the third emitter layer is less than a thickness of the third base layer ([0029]), and a thickness of the fourth emitter layer is less than a thickness of the fourth base layer ([0029]).
Although King does not explicitly disclose a first semiconductor mirror formed between the second subcell and the third subcell, King discloses the use of semiconductor mirror, Bragg reflector, ([0089-0101]) between subcells in order to reflect light back the top cells to be absorbed by the upper cells. Therefore, it would have been obvious to one skilled in the art at the time of the invention to have used the first Bragg reflector between second and third subcells such the light that can be absorbed by second subcell can be reflected back to the second subcell.
King further discloses that one of the cells of the multijunction solar cell 10 is a cell that comprises low-bandgap absorber region (LBAR) ([0111]). King further discloses that the second subcell (cell 2) is made of GaIn(P)As (see fig. 35), and the cell that comprises LBAR can be made of GaIn(P)As ([0277]). The LBAR structure comprises thicker emitter than the base (see figures 6 and 7, and also [0028] that shows the emitter thickness is 50-100% of the total thickness).
Therefore, it would have been obvious to one skilled in the art at the time of the invention to have formed the second subcell with LBAR structure, as disclosed by King ([0277]) because choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success is obvious (KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007)).
King further discloses that the second subcell (cell) is a GaIn(P)As subcell that has a bandgap of 1.3-107 eV (fig. 35 and [0277]). However, King does not explicitly disclose that the second emitter layer comprising InGaP and the second base layer comprising InGaAsP.
Suarez discloses a multijunction solar cell wherein GaInPAs subcell (InGaAsP subcell) ([0069]) comprises InGaP emitter and InGaAsP base ([0069]). Therefore, Suarez explicitly discloses InGaP and InGaAsP are well-known semiconductor materials that can be used to form GaInPAs subcell.
Therefore, it would have been obvious to one skilled in the art at the time of the invention to have used InGaP emitter and InGaAsP base as taught by Suarez to form the GaInPAs subcell of King because selection of a known material based on its suitability for its intended use (to form the base and emitter) supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945). See MPEP § 2144.07.
King further discloses that the emitter of the second subcell has lower doping that the base layer of the second subcell (emitter is low-bandgap absorber). Although King does not disclose that the emitter doping of the second subcell is less than the base doping by at least a factor of 3, it is noted that “differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical” (MPEP §2144.05 II A). Instant application as originally filed fails to disclose whether the claimed difference in concentration is critical.
Thus, in absence of evidence of criticality, it would have been obvious to skilled in the art to have determined the dopant concentration of the emitter layer by routine experimentation such that the emitter has the low bandgap as desired. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 2, King further discloses a tunnel diode is arranged between the second subcell and the semiconductor mirror (see fig. 33, that shows the use of tunnel junction between adjacent cells and thus, in between second subcell and the semiconductor mirror).
Regarding claim 3, King further discloses the semiconductor mirror is n-doped ([0089-0101]). King does not explicitly disclose the doping is greater than 5 1017/cm3. However, “differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical” (MPEP §2144.05 II A). Thus, in absence of evidence of criticality, it would have been obvious to skilled in the art to have determined the appropriate doping concentration by routine experimentation such that the semiconductor mirror can reflective light effectively. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claims 4 and 5, King does not explicitly disclose that the thickness of the second emitter layer has a thickness greater than 600 nm, the second base layer has a thickness less than 450 nm. However, selection of element’s dimension is considered to be a matter of design choice, depending upon the dimensions and gradient present in the installation site, among other considerations. In the absence of evidence of criticality, selection of base/emitter layer thickness as claimed is considered obvious to one having ordinary skill in the art. Also note that in Gardner v. TEC Systems, Inc., 725 F.2d 1338, 220 USPQ 777 (Fed. Cir. 1984), cert. denied, 469 U.S. 830, 225 USPQ 232 (1984), the Federal Circuit held that, where the only difference between the prior art and the claims was a recitation of relative dimensions of the claimed device and a device having the claimed relative dimensions would not perform differently than the prior art device, the claimed device was not patentably distinct from the prior art device.
Regarding claim 7, King further discloses the second emitter layer of the second subcell comprises InGaAsP (fig. 35 and [0277]). However, King does not explicitly disclose that the emitter layer of the second subcell has an arsenic content based on the elements of main group V of between 22% and 33% and an indium content based on the elements of the main group III between 52% and 65%, and the lattice constant of the emitter layer is between 0.572 nm and 0.577 nm. However, “differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical” (MPEP §2144.05 II A). Thus, in absence of evidence of criticality, it would have been obvious to skilled in the art to have determined the appropriate amount of In and As by routine experimentation such that the emitter has the desired lattice constant. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 8, King further discloses that the second subcell is designed as a heterocell ([0277], GaInAs emitter/GaInPAs base).
Regarding claim 10, King further discloses that the first subcell has a bandgap of 1.6-2.3 eV (fig. 35) that overlaps with the claimed range of between 1.85 eV and 2.07 eV, the second subcell has a bandgap of 1.3-1.7 eV (fig. 35) that overlaps with the claimed range of between 1.41 eV and 1.53 eV, and the third subcell has a bandgap in a range of 1-1.3 eV (fig. 35) that overlaps with the claimed range of between 1.04 eV and 1.18 eV. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976)) (MPEP § 2144.05 - (I)).
Regarding claim 11, King further discloses that the first subcell comprises AlGaInP (see fig. 35), and thus reads on claimed compound of at least the elements AlInP. However, King does not explicitly disclose that the indium content based on the elements of the main group III is between 64% and 75% and the Al content is between 18% and 32%. However, “differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical” (MPEP §2144.05 II A). Thus, in absence of evidence of criticality, it would have been obvious to skilled in the art to have determined the appropriate amount of In and Al by routine experimentation such that subcell has desired bandgap. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 12, although King does not explicitly show a second semiconductor mirror is arranged between the third subcell and the fourth subcell (see fig. 35), King in a broader disclosure teaches that the use of semiconductor mirror, Bragg reflector, ([0089-0101]) between subcells in order to reflect light back the top cells to be absorbed by the upper cells. Therefore, it would have been obvious to one skilled in the art at the time of the invention to have used the Bragg reflector between fourth and third subcells such the light that can be absorbed by fourth subcell can be reflected back to the fourth subcell.
Regarding claim 13, King further discloses that the LBAR layer or second emitter layer can be formed with graded bandgap (see fig. 8 – emitter has two regions with different material and bandgap), which implies that the emitter layer of the second subcell inherently or implicitly has graded dopant concentration (note that second level bar has no amount of Al). With respect to the claimed dopant concentration, it is noted that “differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical” (MPEP §2144.05 II A). Thus, in absence of evidence of criticality, it would have been obvious to skilled in the art to have determined the dopant concentration of the emitter layer by routine experimentation such that emitter has desired grading. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 14, King further discloses that wherein the second emitter layer of the second subcell comprises a first region and a second region, the first region having a different magnitude of doping than the second region and the second region being formed closer to the second base layer than the first region (see fig. 8).
Regarding claim 15, King further discloses that a fifth subcell between the first and second subcells (see fig. 37).
Regarding claim 17, King further discloses that the emitter of the second subcell has lower doping that the base layer of the second subcell (emitter is low-bandgap absorber). Although King does not disclose that the emitter doping of the second subcell is less than the base doping by at least a factor of 3, it is noted that “differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical” (MPEP §2144.05 II A). Thus, in absence of evidence of criticality, it would have been obvious to skilled in the art to have determined the dopant concentration of the emitter layer by routine experimentation such that the emitter has the low bandgap as desired. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 20, King further discloses the tunnel junction between subcells (see fig. 33) and therefore, there is no direct semiconductor bond is formed between the first, second, third and fourth subcells due to presence of intervening layer (tunnel junction).
Regarding claim 21, King further discloses the magnitude of doping in the first region is greater than the magnitude of doping in the second region (see fig. 8, that shows the region of emitter close the base has lower bandgap or dopoing than the region of the emitter away from the base).
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over King in view of Suarez as applied to claim 1 above, and further in view of Hsu (US 2010/0212729 A1).
Regarding claim 16, King discloses the multijunction solar cell as discussed above. King discloses that the base layer of the second subcell (cell 2) is p-type layer and formed of GaInAsP (as modified by Suarez). However, King does not explicitly disclose that the base layer of the second subcell is doped with carbon and/or wherein the carbon concentration in the base layer of the second solar cell is higher than the zinc concentration.
Hsu discloses a multijunction solar cell wherein carbon is used a p-type dopant ([0074]).
Thus, it would have been obvious to one skilled in the art at the time of the invention to have used the carbon dopant as taught by Hsu to form the p-type base layer of the second subcell of King because selection of selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945). See MPEP § 2144.07.
Claim 18 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over King in view of Suarez as applied to claim 1 above, and further in view of Derkacs (US 2020/0203537 A1).
Regarding claim 18 and 19, King does not explicitly disclose that the Al content in the first or second semiconductor mirror is greater than 24%.
Derkacs discloses a multijunction solar cell wherein semiconductor mirror (DBR layer) is made of AlxGa1-x(In)As wherein Al content is 0<x<100 ([0081]).
Thus, it would have been obvious to one skilled in the art at the time of the invention to have used the AlxGa1-x(In)As wherein Al content is 0<x<100 ([0081]) as taught by Derkacs to form the first and second semiconductor mirrors of King because selection of selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945). See MPEP § 2144.07.
Thus, King as modified by Derkacs discloses the Al content is greater than 0% and less than 100%. Thus, claimed range (greater than 24%) overlaps with the disclosed range.
In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976)) (MPEP § 2144.05 - (I)).
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/process/file/efs/guidance/eTD-info-I.jsp.
Claims 1-21 are rejected on the ground of nonstatutory double patenting as being unpatentable over claim 1-15 of U.S. Patent 11,374,140. Although the claims at issue are not identical, they are not patentably distinct from each other because the claims of the patent encompass all the limitations of the pending claims.
Response to Arguments
Applicant's arguments with respect to claims 1-5, 7-8 and 10-21 have been considered but are moot in view of the new ground(s) of rejection as necessitated by the amendments.
Applicant argues that King as modified Suarez does not disclose that the second emitter doping is less than second base doping by at least a factor of 3.
King explicitly discloses that the emitter of the second subcell has lower doping that the base layer of the second subcell (emitter is low-bandgap absorber). Although King does not disclose that the emitter doping of the second subcell is less than the base doping by at least a factor of 3, it is noted that “differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical” (MPEP §2144.05 II A). Instant application as originally filed fails to disclose whether the claimed difference in concentrations is critical.
Thus, in absence of evidence of criticality, it would have been obvious to skilled in the art to have determined the dopant concentration of the emitter layer by routine experimentation such that the emitter has the low bandgap as desired. “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 2018/0062017 A1 to Derkacs discloses a multi-junction solar cell having metamorphic buffer layer between Ge and III-V subcells (fig. 1). Derkacs further discloses more III-V subcells (see fig. 1), and a DBR layer placed between Ge and III-V subcell (see fig. 1).
Correspondence/Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to GOLAM MOWLA whose telephone number is (571)270-5268. The examiner can normally be reached on M-Th, 7am - 4pm.
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/GOLAM MOWLA/Primary Examiner, Art Unit 1721