DETAILED ACTION
This is the third Office Action regarding application number 18/635,804, filed on 04/15/2024, which is a continuation of 16/826,777, filed on 03/23/2020, which claims foreign priority to DE 102019002034.0, filed on 03/22/2019.
This action is in response to the Applicant’s Response received 03/22/2026.
Status of Claims
Claims 1-22 are currently pending.
Claims 1, 19, and 22 are amended.
Claims 1-22 are examined below.
No claim is allowed.
Response to Arguments
The Applicant’s arguments received 03/22/2026 have been carefully considered but they are not found persuasive.
The applicant states that “there is a five-compartment [subcell] solar cell with an SC5 supercell in King as a heterocell”. Remarks 10. The examiner agrees with the applicant’s statement. The applicant next asserts that this fifth subcell is not “formed as a heterocell”. The examiner disagrees. The plain language of “formed as a heterocell” is interpreted to mean that if the final resulting structure is a heterocell, then it was also “formed” as a heterocell. The examiner respectfully requests that the applicant further elaborate its position explaining what more is required by reciting the phrase “formed as a heterocell”. The examiner was unable to determine any other required feature or function of the fifth subcell upon review of the applicant’s other remarks or its application-as-filed.
The applicant also states that “Figure 43 of King clearly and unambiguously shows that an emitter made of GalnP, i.e. without aluminum, achieves a much higher absorption” yielding “a clear and unambiguous result for one of ordinary skill in the art to avoid aluminum in the emitter layer at all costs.” Id. The examiner does not understand KING to provide such a proscriptive direction. Instead, KING states that “the emitter for both the low-Al and Al-free cases benefits the current collected in both the short wavelength and long wavelength regions of the external quantum efficiency (EQE) curves”. KING, para. 370. The examiner believes the straightforward meaning of KING's statement is that either low amounts of aluminum or aluminum-free compositions are beneficial to the device performance. Therefore, the fifth subcells of both claim 1 (low-Al) and claim 22 (Al-free) are described in the KING reference.
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The applicant also states that KING fails to describe how the aluminum content is arranged in the emitter and the base of a top cell as a heterocell under the condition of the cell consisting essentially of AllnGaP with the indium content greater than 63%. Remarks 10. The examiner notes that other prior art references are relied upon to teach the claimed indium content amounts, so the applicant’s remark is understood by the examiner to be directed at the KING reference individually, rather than discussing how the combination of prior art references does not render the claims to be obvious to a person having ordinary skill in the art.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-3, 6-10, 15-17, 19, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over KING (US 2017/0069779 A1) in view of GUTER (US 2012/0138130 A1).
Regarding claim 1, KING teaches a stacked, monolithic, upright metamorphic, terrestrial concentrator solar cell comprising (upright vs. inverter metamorphic describes the process of product construction, and has limited patentable significant here in the preamble or in the final structure of the recited produce claim):
exactly five subcells (5-junction solar cell, Fig. 36); and
wherein a first subcell has a first lattice constant and a first band gap and consists essentially of germanium (cell 5, Fig. 36),
wherein a second subcell is arranged above the first subcell and has a second lattice constant and a second band gap, and comprises GaInAs or consists essentially of GaInAs (cell 4),
wherein a third subcell is arranged above the second subcell and has the third lattice constant and a third band gap, and comprises AlGaInAs or consists essentially of AlGaInAs (cell 3),
wherein a fourth subcell is arranged above the third subcell and has a fourth lattice constant and a fourth band gap, and comprises InP (cell 2 of GaInP),
wherein a fifth subcell is formed as a heterocell and arranged above the fourth subcell and has a fifth lattice constant and a fifth band gap (cell 1 of AlGaInP; Fig. 43 and para. 370 describe two example embodiments where the fifth subcell base is 2.05 eV AlGaInP and the emitter can be either of a low-aluminum 1.95 eV AlGaInP material or an aluminum-free 1.88 eV GaInP emitter, either thus forming a heterocell with the non-identical subcell base material),
wherein the first bandgap is less than the second bandgap which is less the third bandgap wish is less the fourth bandgap which is less fifth bandgap (Fig. 36 illustrates the claimed bandgap relationships),
wherein the first lattice constant is less than the second lattice constant (the lattice constant of Ge is known to be less than the lattice constant of GaInAs),
wherein all of the semiconductor layers of the concentrator solar cell arranged above the first subcell are epitaxially produced on the preceding subcell (epitaxial semiconductor growth process, para. 255), and
wherein the fifth subcell comprises a base layer and an emitter layer (Fig. 36 illustrates the base/emitter layers) and consists essentially of AlInGaP, with an aluminum content less than 25%, based on group III elements (KING teaches the fifth subcell may have an aluminum content of 10%);
wherein the first, second, third, and fourth lattice constants differ from one another by less than 0.2% (“the lattice constant of adjacent subcells differs by 0.5% or less,” para. 352),
wherein any of the first, second third, and fourth lattice constants is greater than 5.72x10-10 m (“the lattice constant of adjacent subcells is equal to or is within approximately 0.1% of the lattice constant of InP, or 5.8688 angstroms”, para. 353; the examiner notes that 5.72x10-10 m equals 5.72 angstroms);
wherein the fifth subcell has a bandgap less than 1.98V and greater than 1.74 eV (fifth top subcell has bandgap between 1.6-2.3 eV, overlapping claimed range and obvious).
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KING does not disclose expressly an embodiment with five subcells that has a metamorphic buffer layer as claimed, or that the fifth subcell consists essentially of AlInGaP with an indium content greater than 63%, based on group III elements.
Also, KING teaches the addition of a metamorphic buffer (optional metamorphic buffer 52, Fig. 33) between a germanium subcell with a first lattice constant and a GaInAs subcell having a second lattice constant, wherein the metamorphic buffer is arranged between the first subcell and the second subcell and has the first lattice constant on a bottom side facing the first subcell and has the second lattice constant on a top side facing the second subcell (optional metamorphic buffer layer illustrated in Figure 33 is between the first and second subcells (lower subcells) and is lattice matched as recited, para. 343).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify KING and add a metamorphic buffer layer between the Ge and GaInAs first and second subcells because Ge and GaInAs have different lattice constants and the inclusion of the buffer layer provides for a lattice constant transition that helps reduce the density of harmful dislocations caused by lattice mismatch (KING, para. 11).
GUTER teaches a multi-junction solar cell having an AlInGaP material with an indium content up to 65% (para. 14).
It would have been obvious to skilled artisans to modify KING and incorporate an indium content of up to 65% as taught by GUTER in order to control lattice constant and bandgap that are affected by the indium content (GUTER, para. 14).
Regarding claim 2, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein the fourth subcell and/or the fifth subcell has GaInP or consists essentially of GaInP (KING, Fig. 36 indicates that the fourth and fifth subcell include GaInP).
Regarding claim 3, modified KING teaches or would have suggested the concentrator solar cell according to claim 2, wherein the fourth subcell has an aluminum content, based on the group III elements, of 0% or less than 5% or less than 1% (KING, Fig. 36 indicates that the fourth subcell may include only GaInP with no aluminum).
Regarding claim 6, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein the metamorphic buffer has a sequence of at least three and at most ten layers and/or that the metamorphic buffer has a layer thickness of at least 0.5 µm and at most 4 µm (KING, Fig. 33 illustrates a metamorphic buffer with a sequence of five layers).
Regarding claim 7, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein the second subcell has a lattice constant greater than 5.72×10-10 m and/or a band gap greater than 1.07 eV (0.9-1.3 eV, KING, Fig. 36) and/or an indium content less than 24.5%.
Regarding claim 8, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein the third subcell has a band gap between 1.34 eV and 1.45 eV or between 1.3 eV and 1.5 eV (1.2-1.6 eV, KING, Fig. 36).
Regarding claim 9, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein the fourth subcell has a band gap between 1.61 eV and 1.69 eV or between 1.58 eV and 1.72 eV (1.5-1.9 eV, KING, Fig. 36).
Regarding claim 10, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein the concentrator solar cell has a window layer (window layer, KING, paras. 358, 363, 364), wherein the window layer is arranged above the fifth subcell and has a lattice constant that is at least 0.5% or at least 0.7% lower than the second lattice constant (layers have may lattice constants within 1% of each other, KING, paras. 351 and 352).
Regarding claim 15, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein a tunnel diode is arranged between the first subcell and the second subcell (layers 10 between the subcells can be tunnel junctions, i.e., tunnel diodes, KING, para. 367).
Regarding claim 16, modified KING teaches or would have suggested the concentrator solar cell of claim 1, wherein a corresponding tunnel diode is arranged between each two successive subcells of the concentrator solar cell (KING, Fig. 36 illustrates a tunnel diode/junction between each adjacent subcell, and the examiner asserts that each subcell includes a p-n junction and these junctions include both an emitter and a base).
Regarding claim 17, modified KING teaches or would have suggested the concentrator solar cell of claim 16, wherein the tunnel diode is arranged between the first subcell and the second subcell is arranged below the metamorphic buffer (KING, Fig. 33 illustrates an embodiment that arranges the tunnel junction/diode below the metamorphic buffer).
Regarding claim 19, modified KING teaches or would have suggested the concentrator solar cell of claim 1, wherein the fifth subcell is formed as a heterocell, and wherein the aluminum content of the base is higher than the aluminum content of the emitter (Al-free GaInP emitter and AlGaInP base hetero top cell, KING, Fig. 43 and para. 367).
Regarding claim 22, KING teaches a stacked, monolithic, upright metamorphic, terrestrial concentrator solar cell comprising (upright vs. inverter metamorphic describes the process of product construction, and has limited patentable significant here in the preamble or in the final structure of the recited produce claim):
exactly five subcells (5-junction solar cell, Fig. 36); and
wherein a first subcell has a first lattice constant and a first band gap and consists essentially of germanium (cell 5, Fig. 36),
wherein a second subcell is arranged above the first subcell and has a second lattice constant and a second band gap, and comprises GaInAs or consists essentially of GaInAs (cell 4),
wherein a third subcell is arranged above the second subcell and has the third lattice constant and a third band gap, and comprises AlGaInAs or consists essentially of AlGaInAs (cell 3),
wherein a fourth subcell is arranged above the third subcell and has a fourth lattice constant and a fourth band gap, and comprises InP (cell 2 of GaInP),
wherein a fifth subcell is formed as a heterocell and is arranged above the fourth subcell and has a fifth lattice constant and a fifth band gap (cell 1 of AlGaInP; Fig. 43 and para. 370 describe two example embodiments where the fifth subcell base is 2.05 eV AlGaInP and the emitter can be either of a low-aluminum 1.95 eV AlGaInP material or an aluminum-free 1.88 eV GaInP emitter, either thus forming a heterocell with the non-identical subcell base material),
wherein the first bandgap is less than the second bandgap which is less the third bandgap wish is less the fourth bandgap which is less fifth bandgap (Fig. 36 illustrates the claimed bandgap relationships),
wherein the first lattice constant is less than the second lattice constant (the lattice constant of Ge is known to be less than the lattice constant of GaInAs),
wherein all of the semiconductor layers of the concentrator solar cell arranged above the first subcell are epitaxially produced on the preceding subcell (epitaxial semiconductor growth process, para. 255), and
wherein the fifth subcell comprises a base layer and an emitter layer (Fig. 36 illustrates the base/emitter layers) and consists essentially of GaInP, with no aluminum (KING teaches the fifth subcell emitter and base in Fig. 36 may be only GaInP, i.e., no aluminum);
wherein the first, second, third, and fourth lattice constants differ from one another by less than 0.2% (“the lattice constant of adjacent subcells differs by 0.5% or less,” para. 352),
wherein any of the first, second third, and fourth lattice constants is greater than 5.72x10-10 m (“the lattice constant of adjacent subcells is equal to or is within approximately 0.1% of the lattice constant of InP, or 5.8688 angstroms”, para. 353; the examiner notes that 5.72x10-10 m equals 5.72 angstroms);
wherein the fifth subcell has a bandgap less than 1.98V and greater than 1.74 eV (fifth top subcell has bandgap between 1.6-2.3 eV, overlapping claimed range and obvious).
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KING does not disclose expressly an embodiment with five subcells that has a metamorphic buffer layer as claimed, or that the fifth subcell has an indium content greater than 63%, based on group III elements.
Also, KING teaches the addition of a metamorphic buffer (optional metamorphic buffer 52, Fig. 33) between a germanium subcell with a first lattice constant and a GaInAs subcell having a second lattice constant, wherein the metamorphic buffer is arranged between the first subcell and the second subcell and has the first lattice constant on a bottom side facing the first subcell and has the second lattice constant on a top side facing the second subcell (optional metamorphic buffer layer illustrated in Figure 33 is between the first and second subcells (lower subcells) and is lattice matched as recited, para. 343).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify KING and add a metamorphic buffer layer between the Ge and GaInAs first and second subcells because Ge and GaInAs have different lattice constants and the inclusion of the buffer layer provides for a lattice constant transition that helps reduce the density of harmful dislocations caused by lattice mismatch (KING, para. 11).
GUTER teaches a multi-junction solar cell having an AlInGaP material with an indium content up to 65% (para. 14; please also see Fig. 1 illustrating the Ga0.35In0.65P upper cell having no aluminum and high indium content).
It would have been obvious to skilled artisans to modify KING and incorporate an indium content of up to 65% as taught by GUTER in order to control lattice constant and bandgap that are affected by the indium content (GUTER, para. 14).
Claims 4, 5, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over KING (US 2017/0069779 A1) and GUTER (US 2012/0138130 A1), and alternatively, further in view of DIMROTH (“5-junction III-V solar cells for space applications”).
Regarding claims 4, 5, and 20, modified KING does not disclose expressly the layer thicknesses of the various subcells. However, KING explains that the specific thicknesses of the subcell layers are result effective variables that are extremely important to select and control, and that they affect the performance of the solar cells in numerous ways, such as subcell voltages, the current densities of each subcell, whether the subcell current densities can be matched to one another as is desired in a series-interconnected multijunction cell, and how the broad solar spectrum is divided into narrower wavelength ranges by the combination of subcell bandgaps to achieve higher sunlight-to-electricity conversion (para. 8). Accordingly, the examiner determines that skilled artisans would have found it obvious to modify KING and adjust the thicknesses of the subcell layers in order to optimize the performance of the solar cells in numerous ways, such as subcell voltages, the current densities of each subcell, whether the subcell current densities can be matched to one another as is desired in a series-interconnected multijunction cell, and how the broad solar spectrum is divided into narrower wavelength ranges by the combination of subcell bandgaps to achieve higher sunlight-to-electricity conversion. The examiner concludes that skilled artisans would find it obvious to select thicknesses within the ranges claimed because these thicknesses would be recognized as ideal dimensions to achieve the desired performance outcomes.
Alternatively, DIMROTH teaches a five-junction solar cell having a second cell layer thickness of 1.5 micrometers and a fourth subcell layer thickness less than 1.5 micrometers (Table 1).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify KING and use the subcell thicknesses taught by DIMROTH for the claimed subcell layers in order to achieve a desired photoelectric conversion performance.
Claims 11-14 are rejected under 35 U.S.C. 103 as being unpatentable over KING (US 2017/0069779 A1) and GUTER (US 2012/0138130 A1), and further in view of MAHAJAN (EP 1498960 A2).
Regarding claims 11-14, modified KING teaches or would have suggested the concentrator solar cell according to claim 1, wherein the metamorphic buffer has a sequence of layers, but does not disclose expressly that a lattice constant of the metamorphic buffer: increases starting from a lowest layer of the sequence with the first lattice constant to an uppermost layer of the sequence with the second lattice constant (claim 11), first increases starting from a lowest layer of the sequence and then decreases from layer to layer or first decreases and then increases (claim 13), or increases from layer to layer starting at a lowest layer of the sequence up to a maximum and then decreases from layer to layer up to the first second lattice constant at an uppermost layer of the sequence (claim 14). KING teaches that the metamorphic buffer comprises more than three layers (claim 22) and the lattice constant increases layer to layer (claim 12).
MAHAJAN teaches a metamorphic buffer layer where the lattice constant throughout the layer is configured to either “vary monotonically” or “vary in a non-monotonic manner” (paras. 43-44). MAHAJAN teaches that any variation can be used so long as the lattice constants at the lowest and uppermost layer surfaces match the lattice constants of the adjoining layers (para. 44). MAHAJAN reports that by selecting from the finite number of configurations (monotonic and non-monotonic), the metamorphic buffer layer can maintain the mechanical integrity of the device and allows the joining of different layer materials (para. 46).
It would have been obvious to skilled artisans to modify KING and configure the metamorphic buffer layer sequence in a manner of either monotonic or non-monotonic as taught by MAHAJAN because this modification requires only the simple selection from a finite number of identified, predictable solutions, with a reasonable expectation of success, with the desired outcome of providing mechanical integrity of the device through the joining of materials having different layer lattice constants. (See also how MAHAJAN teaches the x1, x2, x3 relationships identical to those disclosed in the applicant’s specification.) The examiner further finds that MAHAJAN is analogous art that involves the conversion of light to electrical charge within a semiconductor stacked structure.
Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over KING (US 2017/0069779 A1) and GUTER (US 2012/0138130 A1), and further in view of FUHRMANN (US 2016/0133775 A1).
Regarding claim 18, modified KING teaches or would have suggested the concentrator solar cell of claim 1, but does not disclose expressly that the metamorphic buffer has a dopant concentration greater than 5×1017/cm3.
FUHRMANN teaches a solar cell stack having a metamorphic buffer with a dopant concentration up to 1×1019/cm3 (para. 20). FUHRMANN teaches that the doping of the metamorphic buffer layer reduces dislocations, making it possible to select the bandgap energy in such a way that the total efficiency of the solar cell stack is increased (para. 13).
It would have been obvious to skilled artisans to modify KING and dope the metamorphic buffer with a dopant concentration up to 1×1019/cm3 as taught by FUHRMANN to increase the total efficiency of the solar cell stack.
Claim 21 rejected under 35 U.S.C. 103 as being unpatentable over KING (US 2017/0069779 A1) in view of GUTER (US 2012/0138130 A1) as applied to claim 1 above, and further in view of HOFFMAN (US 2012/0285519 A1).
Regarding claim 21, modified KING teaches or would have suggested the concentrator solar cell of claim 1, but does not disclose expressly that the emitter layer resistance of the emitter layer of the fifth subcell is less than 1500 ohm/square or less than 1000 ohm/square.
KING also reports that the lateral conductivity of the emitter layer (i.e., the inverse of sheet layer resistance) is important because charge carriers must move to the electrical gridlines with minimum resistive loss (para. 364). KING further reports that the material composition must be optimized in order to maximize cell efficiency and to maximize the emitter layer conductivity.
HOFFMAN teaches a multi-junction solar cell having an AlInGaP material forming the top subcell and a sheet resistance of the top cell is less than 300 ohms/square (Figs. 1-2 and para. 43).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify KING and configure the top subcell to have a sheet resistance of less than 300 ohms/square as taught by HOFFMAN in order to maximize cell efficiency as directed by KING.
Conclusion
No claim is allowed.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANGELO TRIVISONNO whose telephone number is (571) 272-5201 or by email at <angelo.trivisonno@uspto.gov>. The examiner can normally be reached on MONDAY-FRIDAY, 9:00a-5:00pm EST. The examiner's supervisor, NIKI BAKHTIARI, can be reached at (571) 272-3433.
/ANGELO TRIVISONNO/
Primary Examiner
Prosecution Insights