DETAILED ACTION
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 .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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, 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 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 18-19, 33-38 and 43-44 are rejected under 35 U.S.C. 103 as being unpatentable over Choi et al. (US 2014/0338747) in view of Westerberg et al. (US 2016/0284913).
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Regarding claim 18, Choi discloses a back-side contact solar cell in Annotated Figure 5 above comprising:
a semiconductor substrate (base area 110) comprising a front side and a back side ([26] and Annotated Figure 5 above) and having a first dopant concentration (base area 110 has a low concentration of a first dopant, [27]),
a doped region on the front side (front surface field 130), having a second dopant concentration greater than the first dopant concentration ([29], the front surface field has a higher doping concentration than the base area 110),
a first passivation layer (tunnelling layer 30) on the back side of the semiconductor substrate (110) ([37]-[38]),
a highly doped silicon layer (20) having a first polarity (second conductivity type dopant) on the first passivation layer ([40] and [31]),
doped base regions having a second polarity formed in areas of the back side of the semiconductor substrate exposed through removed portions of both the first passivation layer (30) and the highly doped silicon layer (20) (See Annotated Figure 5 above and [38]),
highly doped base regions (120) having the second polarity (first conductivity type) in and passing through the doped base regions into the semiconductor substrate (See Annotated Figure 5 above and [26]-[28]),
electrodes of the first polarity (44) and electrodes of the second polarity (42) on the back side ([43]), the electrodes of the first polarity (44) being on the highly doped silicon layer (20) and the electrodes of the second polarity (42) directly electrically and mechanically contacting the semiconductor substrate (110) via the highly doped base regions (120) (Figure 5 and [43]-[44]).
Choi does not disclose that the doped base regions have a third dopant concentration in the back side of the semiconductor substrate, wherein the third dopant concentration is greater than the first dopant concentration and the highly doped base regions have a fourth dopant concentration higher than each of the second and third dopant concentrations.
Westerberg discloses a back-side contact solar cell in Figure 1F comprising:
a semiconductor substrate (100) comprising a front side (101) and a back side (102) and having a first dopant concentration ([42]),
doped base regions (first conductivity type lightly doped regions 104) having a first polarity in the back side of the semiconductor substrate (100) having a dopant concentration is greater than the first dopant concentration ([43]-[44]),
highly doped base regions (first conductivity type highly doped regions 106) having the first polarity in and passing through the doped base regions (104) into the semiconductor substrate (100) (Figure 1F and [46]-[47]), the highly doped base regions (106) having a fourth dopant concentration higher than the doping concentration of the doped base regions (104) ([46]-[47] and [63]).
It would have been obvious to one having ordinary skill in the art at the time the invention was filed to modify the device of Choi such that the doped base regions have a third dopant concentration that is greater than the first dopant concentration and the highly doped base regions have a fourth dopant concentration higher than each of the second and third dopant concentrations, as taught by Westerberg, because the dopant concentrations taught by Westerberg increase the efficiency of the device (Westerberg, [3] and [36]).
Regarding claim 19, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses a second passivation layer (insulating layer 24) on the doped base regions and the highly doped base regions (Figure 5 and [87] and [94]), the second passivation layer (24) has a thickness greater than the first passivation layer (20) (Figure 5, the second passivation layer extends from the substrate vertically past the first passivation layer and thus necessarily has a thickness greater than the first passivation layer).
Regarding claim 33, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the electrodes of the second polarity (42) physically contact only the highly doped base regions (120) (Figure 1).
Regarding claim 34, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the first polarity is p-type, and the second polarity is n-type ([30]-[31]).
Regarding claim 35, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the doped region (130) has the second polarity (front surface field has the same polarity as the doped and highly doped base regions, [27]-[29]).
Regarding claim 36, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the electrodes of the first polarity (44) contact the highly doped silicon layer (20), but do not penetrate the first passivation layer (30) (Figure 5).
Regarding claim 37, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the electrodes of the first polarity (44) contact the highly doped silicon layer (20), partially penetrate the first passivation layer, and contact the semiconductor substrate (The barrier layer 22 can be interpreted as the first passivation layer, [44]-[45] and Figure 5, it is noted that the term “contact” does not require direct contact).
Regarding claim 38, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the semiconductor substrate (110) has the second polarity ([27]-[29]).
Regarding claim 43, modified Choi discloses all of the claim limitations as set forth above. Westerberg additionally discloses that the doped base regions are between the highly doped base regions and the highly doped silicon layer (Choi Annotated Figure 5), and the highly doped base regions (106) have a greater depth into the semiconductor substrate than the doped base regions (104) (Westerberg, Figure 1F and [46]-[47]).
Regarding claim 44, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the second passivation layer (insulating layer 24) occupies a space above the doped base regions in the removed portions of both the first passivation layer (30) and the highly doped silicon layer (20), between the electrodes of the second polarity (42) and the highly doped silicon layer (20) (Figure 5 and [87]).
Claim 32 is rejected under 35 U.S.C. 103 as being unpatentable over Choi et al. (US 2014/0338747) in view of Westerberg et al. (US 2016/0284913), as applied to claim 18 above, in further view of Kim et al. (US2014/0357008).
Regarding claim 32, modified Choi discloses all of the claim limitations as set forth above. Modified Choi does not disclose that the second dopant concentration is from 1x1017cm-3 to 1x1019 cm-3, the third dopant concentration is from 1x1017cm-3 to 1x1019cm-3, and the fourth dopant concentration is above 2x1019cm-3.
Kim discloses a solar cell in Figure 1 comprising a base substrate (10) having regions with a first dopant concentration from 1x1017cm-3 to 1x1019 cm-3 (30b), and highly doped base regions having a dopant concentration above 2x1019cm-3 (30a) ([72]).
It would have been obvious to one having ordinary skill in the art at the time the invention was filed to modify the device of modified Choi such that the second dopant concentration is from 1x1017cm-3 to 1x1019 cm-3, the third dopant concentration is from 1x1017cm-3 to 1x1019cm-3, and the fourth dopant concentration is above 2x1019cm-3, as taught by Kim, because using known doping concentration values for the solar cell of modified Choi would only require routine skill in the art.
Claims 39-42 are rejected under 35 U.S.C. 103 as being unpatentable over Choi et al. (US 2014/0338747) in view of Westerberg et al. (US 2016/0284913), as applied to claim 19 above, in further view of Bende et al. (WO 2019/059765A1, see equivalent US 2020/0279968 for mapping).
Regarding claim 39 and 40, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the second passivation layer (insulating layer 24) can be a variety of insulating materials such as oxides and nitrides ([94]), but Choi does not explicitly disclose that the second passivation layer comprises silicon dioxide, silicon nitride, aluminum oxide, or a combination thereof and wherein the second passivation layer has one or more refractive indices, and the thickness and the one or more refractive indices of the second passivation layer are optimized to reflect electromagnetic radiation not absorbed by the solar cell back into the solar cell.
Bende discloses a back contact solar cell in Figure 1 comprising a passivation layer (24) covering the rear surface of the cell comprising silicon dioxide, silicon nitride, aluminum oxide, or a combination thereof ([87]) and wherein the passivation layer (24) has one or more refractive indices, and the thickness and the one or more refractive indices of the passivation layer are optimized to reflect electromagnetic radiation not absorbed by the solar cell back into the solar cell ([87]).
It would have been obvious to one having ordinary skill in the art at the time the invention was filed to modify the device of modified Choi such that the second passivation layer comprises silicon dioxide, silicon nitride, aluminum oxide, or a combination thereof and wherein the second passivation layer has one or more refractive indices, and the thickness and the one or more refractive indices of the second passivation layer are optimized to reflect electromagnetic radiation not absorbed by the solar cell back into the solar cell, as taught by Bende, in order to maximize the efficiency of the solar cell.
Regarding claim 41, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses a third passivation layer (50) on the front side (Figure 5 and [34]-[36]), but Choi does not explicitly disclose that the third passivation layer has a thickness greater than the first passivation layer.
Bende discloses a back contact solar cell in Figure 1 comprising a tunneling passivation layer (12) on a rear surface of the cell ([40]) and an antireflective passivation layer (30, 32, [47]-[49]) on a front side of the cell, wherein the antireflective passivation layer (30, 32) has a thickness greater than the tunneling passivation layer (12) ([40] and [113], layer 12 has a thickness of 2nm or less and layers 30 and 32 have thicknesses of 6nm and 80nm, respectively).
It would have been obvious to one having ordinary skill in the art at the time the invention was filed to modify the device of modified Choi such that the third passivation layer has a thickness greater than the first passivation layer, as taught by Bende, because the thicknesses taught by Bende allow for efficient tunneling and antireflective performance of the first and third passivation layers, respectively. The use of known suitable thicknesses for tunneling and antireflective layers for solar cells only requires routine skill in the art.
Regarding claim 42, modified Choi discloses all of the claim limitations as set forth above. Choi additionally discloses that the third passivation layer (50) has one or more refractive indices, and the thickness and the one or more refractive indices of the third passivation layer are optimized to absorb electromagnetic radiation in the solar cell ([34]-[36]).
Response to Arguments
Applicant's arguments filed 3/08/2026 have been fully considered but they are not persuasive.
Applicant argues that the combination of Choi and Westerberg does not disclose that the doped base regions having a second polarity are formed in areas of the back side of the semiconductor substrate exposed through removed portions of both the first passivation layer and the highly doped silicon layer. Applicant additionally argues that Westerberg does not disclose or suggest doped base regions formed in areas of the back side of the semiconductor substrate exposed through removed portions of a passivation layer and a highly doped silicon layer, as recited in Claim 18, or suggest to one of ordinary skill in the art modifying Choi in order to do so.
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Examiner respectfully disagrees. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Choi discloses that the doped base regions having a second polarity are formed in areas of the back side of the semiconductor substrate exposed through removed portions of both the first passivation layer (30) and the highly doped silicon layer (20) (See Annotated Figure 5 above and [38]) and Westerberg is not being relied on to teach this claimed feature. Thus, the combination of Choi and Westerberg render obvious the limitations in claim 18.
Conclusion
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/LINDSEY A BUCK/Primary Examiner, Art Unit 1728