Ex Parte Cornfeld

Patent Trial and Appeal Board

Oct 25, 2016

13836742 (P.T.A.B. Oct. 25, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/836,742 03/15/2013
128940 7590 10/25/2016
SolAero Technologies Corp,
10420 Research Road SE
Albuquerque, NM 87123
FIRST NAMED INVENTOR
Arthur Cornfeld
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.
A006X 5608
EXAMINER
GONZALEZ RAMOS, MA YLA
ART UNIT PAPER NUMBER
1758
MAILDATE DELIVERY MODE
10/25/2016 PAPER
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.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL
AND APPEAL BOARD
Ex parte ARTHUR CORNFELD
Appeal2015-001555
Application 13/836,742
Technology Center 1700
Before PETER F. KRATZ, BEVERLY A. FRANKLIN, and
MICHAEL P. COLAIANNI, Administrative Patent Judges.
COLAIANNI, Administrative Patent Judge.
DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134 the final rejection of claims
1--18. We have jurisdiction over the appeal pursuant to 35 U.S.C. § 6(b).
We AFFIRM.
Appellant's invention is directed to solar cells and fabrication of solar
cells with the design and specification of the window layer in multi-junction
solar cells based on III-V semiconductor compounds (Spec. i-f 3 ).
Appeal2015-001555
Application 13/836,742
Claim 1 is illustrative (emphasis added to highlight argued
distinctions):
1. A multijunction solar cell comprising:
a surface layer;
an upper first solar subcell disposed below the surface layer and being
composed of a semiconductor material having a first band gap, and the first
solar subcell having a base region and an emitter region;
a window layer disposed directly over the emitter region of the upper
first solar subcell and directly below the surface layer, the window layer
having a increasing gradation in doping from the region in the window layer
adjacent to the emitter region to the region in the window layer adjacent to
the surface layer overlying the window layer so that minority carriers in the
window layer experience an electric field which would tend to drive them in
the direction of the emitter layer; and
a second solar subcell adjacent to said first solar subcell and having a
second band gap smaller than the first band gap and being lattice matched
with the upper first solar subcell.
Appellant appeals the following rejections:
1. Claims 1, 3, 6, and 14-16 are rejected under 35 U.S.C. § 103(a), as
unpatentable over Newman et al., (US 2010/0229926 Al, published
Sept. 16, 2010; hereinafter "Newman"); in view of
Farmer et al., (US 2010/0218819 Al; published Sept. 2, 2010;
hereinafter "Farmer") and Grillot et al., (US 7,951,693; issued May
31, 2011; hereinafter "Grillot").
2. Claims 2, 17, and 18 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Newman in view of Farmer, Grillot and
Nie et al., (US 2012/0104460 Al, published May 3, 2012; hereinafter,
"Nie").
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Application 13/836,742
3. Claims 4, 5, and 12 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Newman in view of Farmer, Grillot, and Misra et
al., (US 2012/0103403 Al; published May 3, 2012; hereinafter
"Misra").
4. Claims 7 and 13 are rejected under 35 U.S.C. § 103(a) as unpatentable
over Newman in view of Farmer, Grillot, Virshup (US 5,342,451;
issued Aug. 30, 1994), and Karam et al., (US 6,150,603; issued Nov.
21, 2000; hereinafter "Karam").
5. Claims 8 and 9 are rejected under 35 U.S.C. § 103(a) as unpatentable
over Newman in view of Farmer, Grillot, Fafard (US 7,863,516;
issued Jan. 4, 2011) and as evidenced by Li, et al., Unintentional
Doping and Compensation Effects of Carbon in Metal-Organic
Chemical-Vapor Deposition Fabriacated ZnO thin Films, Journal of
Vacuum Science and Technology A (2006); hereinafter "Li".
6. Claims 10 and 11 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Newman in view of Farmer, Grillot, and Suh (US
8,507,787; issued Aug. 13, 2013).
Appellant's arguments focus on the subject matter of claim 1 (App. Br. 4-
14). Accordingly, claims not separately argued will stand or fall with our
analysis of the rejection of claim 1. Appellant does not contend that any of
the applied references are unavailable as prior art to the claimed subject
matter. See, Ans. 3-5.
FINDINGS OF FACT & ANALYSIS
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Appellant argues that the Examiner's rejection lacks articulated,
credible reasoning to support the obviousness rejection (App. Br. 4).
Appellant contends that Farmer's teaching of a grading in composition to
yield a grading in bandgap would not have suggested a window layer having
a gradation in doping as required by claim 1 (App. Br. 5). Appellant argues
that Grillot may teach that a layer can be graded in composition or dopant ,
but Grillot does not teach that composition graded layers are equivalent to
dopant graded layers and would lead to the same properties as dopant graded
layers (App. Br. 5-6). Appellant contends that Comfeld's publication US
2013/0139877 Al teaches that variations in composition in adjacent layers
may result in graded band gap (App. Br. 6). Appellant argues that dopant
graded layers can be used to provided increased current to a multi-junction
solar cell as disclosed in i-f 19 of the Specification. Id. Appellant contends
that the Examiner's rationale for using Grillot's teaching that the
semiconductor layers may be composition or dopant graded fails to identify
a problem that using a dopant gradation or compositional gradation would
address or if such a change would have a reasonable expectation of success
(App. Br. 7-8).
Contrary to Appellant's arguments, the Examiner's rejection is based
upon Newman teaching all the limitations in claim 1, except for a window
layer having a dopant gradation as recited in claim 1 (Ans. 5-6). The
Examiner finds that Farmer teaches a solar cell having a window layer that is
compositionally graded so that the bandgap varies from the region in the
window layer adjacent to the layer overlying the window layer so as to
encourage minority carriers that are generated in the window layer to
migrate to the emitter and it can also help reduce drops in electrical potential
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Application 13/836,742
across the window layer (Ans. 6). The Examiner concludes that it would
have been obvious to grade the composition of Newman's window layer as
taught by Farmer in order to achieve the goals taught by Farmer (i.e.,
encouraging directional movement of minority carriers) (Ans. 6-7).
The Examiner finds that Newman as modified by Farmer teaches
modifying the window layer by varying composition rather than doping
(Ans. 7). The Examiner finds that Grillot teaches that a grading structure
may be achieved by creating a change in composition and/or dopant
concentration (Ans. 7). The Examiner concludes that it would have been
obvious to Grillot's doping to form Newman's window layer having a
graded composition as modified by Farmer because grading by doping is
within the ordinary skill of the art and common sense (Ans 7). The
Examiner finds that Grillot teaches that grading by doping leads to
anticipated success (Ans. 7). We understand the Examiner to find that
Grillot teaches that a layer may be successfully graded by providing a
change in the composition of the layers by either doping or compositional
variation. In other words, we understand the Examiner to find that doping is
another way to produce a layer graded in composition (Ans. 24-25).
Although Appellant argues that dopant and compositionally graded
layers may produce layers having different properties, Appellant cites only
his own disclosure in the Specification and a pre-grant publication of the
present inventor as evidence of this alleged difference in properties (App.
Br. 6). Appellant's attorney argument and evidence of the inventor does not
necessarily establish that compositional grading yields a different product
cell than dopant grading. Indeed, the preponderance of the evidence favors
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Application 13/836,742
the Examiner that dopant grading or compositional grading will produce a
graded difference in composition through the layer as taught by Grillot.
The difference in properties argued by Appellant on page 6 of the
Appeal Brief seems to compare the compositional variation in a AlGainAs
material layer with a dopant graded window layer made of AlinP (Spec. i-f
19, 30; App. Br. 6). In other words, Appellant's conclusions regarding
comparison of a compositional graded layer with a dopant graded layer
cannot be said to establish that the properties of the layers would necessarily
be different in a dopant graded window layer as compared to Farmer's
compositionally graded window layer. Rather, Appellant's argument is
contradicted by Farmer that teaches a compositionally graded layer
possesses the same property (i.e., encourages minority carriers to migrate to
the emitter) as claimed by Appellant with regard to a dopant graded layer.
Though Appellant argues that the Examiner has not established that a
gradation in doping would yield a gradation in bandgap (Reply Br. 2), the
variation in bandgap appears to be affected by the composition of the layer
as taught by Farmer (i-f 159). Because dopant grading would affect the
composition of the layer, there is a reasonable basis to find that bandgap
would be affected by the change in composition. Appellant contends that
the density of carriers in a compositionally graded layer is four orders of
magnitudes greater than the density of carriers in a dopant graded layer (i.e.,
1022 vs. 1018) (Reply Br. 3). Appellant fail to cite any evidence to support
the position that the density of carriers in a compositionally graded layer is
"typically on the order of 5 x 1022 atoms cm-3" as argued. Id. Appellant's
mere arguments are insufficient to convince us of reversible error in the
Examiner's rejection.
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The Examiner is not relying on dopant and compositional graded
layers as being equivalent as argued by Appellant. Rather, the Examiner's
position is that dopant grading is another way to achieve compositional
variation in a layer. Grillot's disclosure supports the Examiner's position.
In light of the teachings of Grillot, Farmer, and Newman as a whole, we find
that the Examiner reasonably concluded that it would have been obvious to
form a dopant graded window layer to encourage minority carriers to
migrate to the emitter as taught by Farmer with respect to a compositionally
graded window layer. On this record, we affirm the Examiner's§ 103(a)
rejection over Newman, Farmer and Grillot.
Appellant's only arguments regarding rejections (2) to (4) and (6) is
that the additional references do not cure the alleged deficiencies of
Newman, Farmer and Grillot (App. Br. 9-12, 14). For the reasons discussed
above, we affirm the Examiner's rejection (2) to (4) and (6).
Regarding rejection (5), Appellant argue it is improper to include Li
as an evidentiary reference in a§ 103 (a) rejection (App. Br. 12-13).
Appellant contends that it is unclear if Li is part of the obviousness rejection
or not (App. Br. 13).
The Examiner suggests combining Fafard's p-i-n cell in a compound
semiconductor solar cell grown by metal organic vapor deposition as a
known substitute for p/n stuctures as in Newman (Ans. 17). Fafard does not
teach that the metal organic deposition process is unintentionally doped.
The rejection is clear that Li is relied upon to teach that unintentional doping
of layers deposited by metal organic chemical vapor deposition is typical
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and well-known in semiconductor manufacturing (Ans. 17). The Examiner
relies on Li to show that the intrinsic layer in a p-i-n cell of Newman as
modified by Fafard would be unintentionally doped when formed by metal
organic vapor deposition (Ans. 18).
As we understand the rejection, the Examiner used Li to properly
support the finding that unintentional doping would have occurred in
Fafard's metal organic chemical vapor deposited layer. We note that
Appellant does not dispute the findings of the Examiner with regard to Li.
Appellant's citation to § 2131 of the Manual of Patent Examining
Procedures (MPEP) is directed to the use of more than one reference in a §
102 rejection (App. Br. 12). That section of the MPEP is not relevant to the
35 U.S.C. § 103 rejection present here. Appellant cites to§ 2141.02(V) for
the proposition that obviousness cannot be predicated on what is unknown is
also not applicable here (App. Br. 13). The Examiner cites to Li to establish
what was known in the art with regard to the unintentional doping of metal
organic chemical vapor deposited layers. The Examiner is not basing the
obviousness conclusion on what was unknown, but rather what was known
to the ordinarily skilled artisan.
On this record, we affirm the Examiner's§ 103(a) rejection over
Newman, Farmer, Grillot, Farfard as evidenced by Li.
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).
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ORDER
AFFIRMED
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