DETAILED ACTION
This is the second Office Action regarding application number 18/565,329, filed on 11/29/2023, which is a 371 of PCT/CN2022/120749, filed on 09/23/2022, and which claims foreign priority to CN 202111675167.4 filed on 12/31/2021.
This action is in response to the Applicant’s Response received 11/05/2025.
Status of Claims
Claims 1-12 are currently pending.
Claim 13 is canceled.
Claim 1 is amended.
Claims 14-18 are withdrawn.
Claims 1-12 are examined below.
The rejection of claims under 35 U.S.C. § 103 has been withdrawn in light of the Applicant’s amendments.
Upon further examination, the Office has set forth a new ground of rejection.
No claim is allowed.
Response to Arguments
The Applicant’s arguments received 11/05/2025 have been carefully considered but they are moot in light of the Office’s new ground of rejection.
Claim Rejections - 35 USC § 112
Indefiniteness
The following is a quotation of 35 U.S.C. 112(b):
(B) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
Claims 1-12 are rejected under 35 U.S.C. 112 as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor, or for pre-AIA the applicant regards as the invention.
Claim 1 recites “the N-type silicon layer is doped with a concentration of phosphine”. The examiner determines that this recitation is unclear and indefinite because skilled artisans would not understand how phosphine functions as a semiconductor dopant. Elemental phosphorus would be the “dopant” here producing the n-type conductivity. Gaseous phosphine would not be present within a finished cell piece after PECVD. Claims 2-12 are also rejected because they each incorporate by reference the same indefinite recitation from claim 1. Perhaps the applicant intended to use a word that meant something similar to doping, or at least wishes to differentiate the function of phosphorus doping the silicon crystal lattice and producing n-type conductivity from the possible function of phosphine’s hydrogen atoms. The applicant’s specification and remarks are not very clear about how exactly the “hydrogen atoms can be bound” to avoid film explosion (Remarks 7). The examiner respectfully requests further clarifying explanation from the applicant that would fully inform skilled artisans of the exact physical mechanisms producing the desired film properties.
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 1-12 are rejected under 35 U.S.C. 103 as being unpatentable over YE (CN 105762234 A) in view of STAPINSKI (“Amorphous hydrogenated silicon–carbon as new antireflective coating for solar cells”) and ZENG (CN 109786476 A).
Regarding claim 1, YE teaches a process for producing a cell piece, comprising the following steps:
forming a silicon oxide layer on a backside of an N-type silicon wafer (“pre-treating the n-type silicon wafer to form a silicon oxide layer” para 39);
forming an N-type silicon layer on the silicon oxide layer by PECVD (“forming two or more doped thin film silicon layers”, para. 39; PECVD, para. 56), wherein phosphine and hydrogen are introduced when preparing the N-type silicon layer, such that the N-type silicon layer is doped with a concentration of phosphorus (paras. 19-20),
wherein a phosphine concentration of the N-type silicon layer is within a first preset concentration range (doping concentrations are selected to be within a chosen range), and performing a high-temperature annealing process (para. 68: “annealed at a high temperature”),
and forming a backside electrode (“forming a back electrode”, “a layer of Ag metal back electrode”).
YE does not disclose expressly forming an anti-reflection layer on the N-type silicon layer or the backside electrode on the anti-reflection layer. YE also does not disclose expressly that methane and nitrous oxide are introduced when preparing the N-type silicon layer.
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STAPINSKI teaches that silicon carbide thin films are attractive as antireflection coatings for silicon solar cells (“Introduction” section). The films are grown using silane and methane as reactive gases, and the methane content can be varied between 14%-75% (pg. 1406). STAPINSKI reports that the SiC reflective coating improves solar cell efficiency (pg. 1409).
Skilled artisans would have found it obvious to modify YE and add a silicon carbide antireflection coating in order to improve solar cell efficiency as taught by STAPINSKI.
ZENG teaches PECVD process of forming a cell piece, wherein phosphine, methane, hydrogen, and nitrous oxide are introduced when preparing the N-type silicon layer (Embodiment 6), then performs annealing and passivation by heating.
Skilled artisans would have found it obvious to modify YE and introduce phosphine, methane, hydrogen, and nitrous oxide to prepare a N-type silicon layer in order to form a passivated interface between silicon-containing semiconductor layers, as instructed by and well-known from ZENG.
Additionally, the examiner asserts that the prior art PECVD process uses the same machinery, elemental materials, and process ranges as the applicant’s claimed process, and thus would be expected by skilled artisans to produce a substantially identical product, including a cell piece where “the N-type silicon layer is doped with a concentration of phosphine” because modified YE also uses phosphine.
Regarding claim 2, modified YE teaches the process for producing the cell piece according to claim 1, wherein the step of forming the N-type silicon layer on the silicon oxide layer comprises:
forming a first N-type silicon layer on the silicon oxide layer,
wherein a phosphine concentration of the first N-type silicon layer (1e16) is within the first preset concentration range (doping concentrations are selected to be within a chosen range); and
forming a second N-type silicon layer on the first N-type silicon layer,
wherein a phosphine concentration of the second N-type silicon layer (1e19-1e22) is within the first preset concentration range, and
the phosphine concentration of the second N-type silicon layer is greater than the phosphine concentration of the first N-type silicon layer (YE, para. 39 describes that the second N-type silicon layer has a greater phosphorus concentration than the first N-type layer closer to the silicon oxide layer).
Regarding claim 3, modified YE teaches the process for producing the cell piece according to claim 2, wherein the step of forming the second N-type silicon layer on the first N-type silicon layer comprises:
wherein the phosphine concentration of the second N-type silicon layer is at least twice the phosphine concentration of the first N-type silicon layer.
YE states that “the phosphorus doping achieved by introducing phosphine is achieved by increasing the flow rate of phosphine to gradually increase the phosphorus doping concentration” and “PH3> with a flow rate of 0.5sccm” (para. 59). YE also states that “changing the doping concentration in the prepared doped thin film silicon layer by controlling the flow rate and ratio of the introduced reaction gas” (para. 48). Thus skilled artisans are so directed to select appropriate flow rates and concentration ratios of the reaction gases to produce the described layers, and this would be considered obvious by ordinary skilled artisans using well-known chemical engineering concepts and general knowledge and logic. Setting the phosphine concentration of the second layer to be twice the first layer would achieve the results described by YE and would not lead to any surprising or unexpected results, as YE adequately describes the expected outcome from the adjustment of flow rates and concentration of the reactive gases.
Regarding claim 4, modified YE teaches the process for producing the cell piece according to claim 2, wherein the step of forming the first N-type silicon layer on the silicon oxide layer,
wherein the phosphine concentration of the first N-type silicon layer is within the first preset concentration range comprises:
introducing a phosphine of less than or equal to 1000 sccm.
YE states that “the phosphorus doping achieved by introducing phosphine is achieved by increasing the flow rate of phosphine to gradually increase the phosphorus doping concentration” and “PH3> with a flow rate of 0.5sccm” (para. 59). YE also states that “changing the doping concentration in the prepared doped thin film silicon layer by controlling the flow rate and ratio of the introduced reaction gas” (para. 48). Thus, skilled artisans are so directed to select appropriate flow rates and concentration ratios of the reaction gases to produce the described layers, and this would be considered obvious by ordinary skilled artisans using well-known chemical engineering concepts and general knowledge and logic. Further, the examiner determines that skilled artisans would quickly understand that the volumetric flow rate could be changed to have a greater value or proportion in order to process larger numbers and/or sizes of cell pieces. The claimed range values for phosphine would not be considered surprising or transformative of the final product produced. MPEP 2144.04(IV)(A).
Regarding claim 5, modified YE teaches the process for producing the cell piece according to claim 4, wherein the step of forming the first N-type silicon layer on the silicon oxide layer,
wherein the phosphine concentration of the first N-type silicon layer is within the first preset concentration range comprises:
introducing a phosphine of greater than or equal to 500 sccm and less than or equal to 1000 sccm.
YE states that “the phosphorus doping achieved by introducing phosphine is achieved by increasing the flow rate of phosphine to gradually increase the phosphorus doping concentration” and “PH3 with a flow rate of 0.5sccm” (para. 59). YE also states that “changing the doping concentration in the prepared doped thin film silicon layer by controlling the flow rate and ratio of the introduced reaction gas” (para. 48). Thus, skilled artisans are so directed to select appropriate flow rates and concentration ratios of the reaction gases to produce the described layers, and this would be considered obvious by ordinary skilled artisans using well-known chemical engineering concepts and general knowledge and logic. Further, the examiner determines that skilled artisans would quickly understand that the volumetric flow rate could be changed to have a greater value or proportion in order to process larger numbers and/or sizes of cell pieces. The claimed range values for phosphine would not be considered surprising or transformative of the final product produced. MPEP 2144.04(IV)(A).
Regarding claim 6, modified YE teaches the process for producing the cell piece according to claim 2, wherein the step of forming the second N-type silicon layer on the silicon oxide layer,
wherein the phosphine concentration of the second N-type silicon layer is within the first preset concentration range, and
the phosphine concentration of the second N-type silicon layer is greater than the phosphine concentration of the first N-type silicon layer comprises:
introducing a phosphine of greater than or equal to 2000 sccm.
YE states that “the phosphorus doping achieved by introducing phosphine is achieved by increasing the flow rate of phosphine to gradually increase the phosphorus doping concentration” and “PH3> with a flow rate of 0.5sccm” (para. 59). YE also states that “changing the doping concentration in the prepared doped thin film silicon layer by controlling the flow rate and ratio of the introduced reaction gas” (para. 48). Thus, skilled artisans are so directed to select appropriate flow rates and concentration ratios of the reaction gases to produce the described layers, and this would be considered obvious by ordinary skilled artisans using well-known chemical engineering concepts and general knowledge and logic. Further, the examiner determines that skilled artisans would quickly understand that the volumetric flow rate could be changed to have a greater value or proportion in order to process larger numbers and/or sizes of cell pieces. The claimed range values for phosphine would not be considered surprising or transformative of the final product produced. MPEP 2144.04(IV)(A).
Regarding claim 7, modified YE teaches the process for producing the cell piece according to claim 6, wherein the step of forming the second N-type silicon layer on the silicon oxide layer,
wherein the phosphine concentration of the second N-type silicon layer is within the first preset concentration range, and
the phosphine concentration of the second N-type silicon layer is greater than the phosphine concentration of the first N-type silicon layer comprises:
introducing a phosphine of greater than or equal to 2500 sccm.
YE states that “the phosphorus doping achieved by introducing phosphine is achieved by increasing the flow rate of phosphine to gradually increase the phosphorus doping concentration” and “PH3> with a flow rate of 0.5sccm” (para. 59). YE also states that “changing the doping concentration in the prepared doped thin film silicon layer by controlling the flow rate and ratio of the introduced reaction gas” (para. 48). Thus, skilled artisans are so directed to select appropriate flow rates and concentration ratios of the reaction gases to produce the described layers, and this would be considered obvious by ordinary skilled artisans using well-known chemical engineering concepts and general knowledge and logic. Further, the examiner determines that skilled artisans would quickly understand that the volumetric flow rate could be changed to have a greater value or proportion in order to process larger numbers and/or sizes of cell pieces. The claimed range values for phosphine would not be considered surprising or transformative of the final product produced. MPEP 2144.04(IV)(A).
Regarding claim 8, modified YE teaches the process for producing the cell piece according to claim 2, wherein the step of forming the first N-type silicon layer on the silicon oxide layer,
wherein the phosphine concentration of the first N-type silicon layer is within the first preset concentration range comprises:
wherein the phosphine concentration of the first N-type silicon layer increases with an increase in a thickness of the first N-type silicon layer (YE, para. 39).
YE states that “the phosphorus doping achieved by introducing phosphine is achieved by increasing the flow rate of phosphine to gradually increase the phosphorus doping concentration” and “PH3> with a flow rate of 0.5sccm” (para. 59). YE also states that “changing the doping concentration in the prepared doped thin film silicon layer by controlling the flow rate and ratio of the introduced reaction gas” (para. 48). Thus, skilled artisans are so directed to select appropriate flow rates and concentration ratios of the reaction gases to produce the described layers, and this would be considered obvious by ordinary skilled artisans using well-known chemical engineering concepts and general knowledge and logic. Further, the examiner determines that skilled artisans would quickly understand that the volumetric flow rate could be changed to have a greater value or proportion in order to process larger numbers and/or sizes of cell pieces. The claimed range values for phosphine would not be considered surprising or transformative of the final product produced. MPEP 2144.04(IV)(A).
Regarding claim 9, modified YE teaches the process for producing the cell piece according to claim 2,
wherein the step of forming the second N-type silicon layer on the silicon oxide layer,
wherein the phosphine concentration of the second N-type silicon layer is within the first preset concentration range, and
the phosphine concentration of the second N-type silicon layer is greater than the phosphine concentration of the first N-type silicon layer comprises:
wherein the phosphine concentration of the second N-type silicon layer increases with an increase in a thickness of the second N-type silicon layer (YE teaches this throughout the reference).
Regarding claim 10, modified YE teaches the process for producing the cell piece according to claim 2, wherein the step of forming the N-type silicon layer on the silicon oxide layer, wherein the phosphine concentration of the N-type silicon layer is within the first preset concentration range comprises:
wherein a concentration of silane introduced during the formation of the first N-type silicon layer is the same as a concentration of silane introduced during the formation of the second N-type silicon layer,
the silane concentration is greater than the phosphine concentration of the first N- type silicon layer (YE, para. 19, “the flow ratio of silane to phosphine is SiH4:PH3 = 1:0.5 to 1:0.01”, and
Modified YE does not disclose expressly that the silane concentration is less than the phosphine concentration of the second N-type silicon layer. However, YE explains that the phosphine flow rate can be increased to increase the phosphorus doping concentration (para. 55), and the examiner determines that skilled artisans would understand these teachings to mean that it is obvious to increase the phosphine concentration to the value necessary to impart the requisite phosphorus concentration, including to values that exceed the silane concentration.
Regarding claim 11, modified YE teaches the process for producing the cell piece according to claim 10, but does not disclose expressly that the step of forming the N-type silicon layer on the silicon oxide layer comprises: introducing the silane of greater than or equal to 1200 sccm and less than or equal to 1800 sccm.
However, the examiner determines that skilled artisans would quickly understand that the volumetric flow rate could be changed to have a greater value or proportion in order to process larger numbers and/or sizes of cell pieces. The claimed range values for silane would not be considered surprising or transformative of final product produced. MPEP 2144.04(IV)(A).
Regarding claim 12, modified YE teaches the process for producing the cell piece according to claim 10, wherein the step of the concentration of silane introduced during the formation of the first N-type silicon layer is the same as the concentration of silane introduced during the formation of the second N-type silicon layer further comprises:
introducing methane, wherein a methane concentration is less than or equal to three times of the silane concentration (STAPINSKI suggests a methane concentration below 25% of silane; overlapping range).
Conclusion
No claim is allowed.
The Applicant’s amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). The Applicant is reminded of the extension of time policy as set forth in 37 C.F.R. § 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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