United States Patent and Trademark Office
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
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
13/161,081 06/15/2011 AHMED ABOU-KANDIL YOR920110187US1 4685
(163-409)
49267 7590 01/30/2018
TUTUNJIAN & BITETTO, P.C.
401 Broadhollow Road, Suite 402
Melville, NY 11747
EXAMINER
MARTIN, BETHANY LAMBRIGHT
ART UNIT PAPER NUMBER
1758
NOTIFICATION DATE DELIVERY MODE
01/30/2018 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
docketing@tb-iplaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte AHMED ABOU-KANDIL, KEITH E. FOGEL,
AUGUSTIN J. HONG, JEEHWAN KIM, and DEVENDRA K. SADANA
Appeal 2016-002206
Application 13/161,081
Technology Center 1700
Before CHRISTOPHER C. KENNEDY, JULIA HEANEY, and
JEFFREY R. SNAY, Administrative Patent Judges.
SNAY, Administrative Patent Judge.
DECISION ON APPEAL1
Appellants2 appeal under 35 U.S.C. § 134(a) from the Examiner’s
decision rejecting claims 1—4, 6-9, and 26. We have jurisdiction under
35 U.S.C. § 6(b).
We affirm.
1 We cite to the Specification (“Spec.”) filed June 15, 2011; Final Office
Action (“Final Act.”) dated February 4, 2015; Appellants’ Appeal Brief
(“App. Br.”) dated July 6, 2015; Examiner’s Answer (“Ans.”) dated October
13, 2015, and Appellants’ Reply Brief (“Reply Br.”) dated December 14,
2015.
2 Appellants identify International Business Machines Corporation as the
real party in interest. App. Br. 4.
Appeal 2016-002206
Application 13/161,081
BACKGROUND
The invention relates to fabricating a photovoltaic device, such as a
solar cell. Spec. 1,6. According to Appellants’ Specification, hydrogen
plasma treatment of an amorphous silicon layer forms seed sites from which
a microcrystalline silicon junction layer may be grown. Id. 7-9. The
junction’s microcrystalline structure permits a greater active doping
concentration, thereby advantageously increasing conductivity and overall
cell efficiency. Id.*\| 35. Claim 1—the sole independent claim on appeal—
reads:
1. A method for fabricating a photovoltaic device,
comprising:
forming a light-absorbing semiconductor structure on a
transmissive substrate including a first conductivity doped layer
of amorphous silicon or microcrystalline silicon;
forming an intrinsic semiconductor layer on the first
doped layer, wherein the intrinsic semiconductor layer includes
an amorphous material of silicon;
treating the intrinsic semiconductor layer with a
hydrogen plasma for a plasma treatment time ranging from
between about 250 to about 500 seconds to form a layer of
silicon seeds from the amorphous material of the intrinsic
semiconductor layer wherein increasing plasma treatment time
increases efficiency and fill factor of the photovoltaic device;
and
forming a first tunnel junction layer on the intrinsic
semiconductor layer by growing microcrystals from the layer of
silicon seeds, the microcrystals being present in a second
conductivity doped layer of microcrystalline silicon, wherein
reliance on increasing dopant concentration in the
microcrystalline silicon to increase efficiency and fill factor of
the photovoltaic device is reduced by said increasing the plasma
treatment time within the range from between 250 to about 500
seconds.
2
Appeal 2016-002206
Application 13/161,081
App. Br. 29 (Claims Appendix).
REJECTIONS3
I. Claims 1—4, 6-9, and 26 stand rejected under 35 U.S.C. § 112, first
paragraph, as failing to comply with that statute’s written description
requirement.
II. Claims 1—4, 6-9, and 26 stand rejected under 35 U.S.C. § 112, second
paragraph.
III. Claims 1-4, 6-8, and 26 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Choi I,4 Choi II,5 Pemet,6 and Pangal.7
IV. Claim 9 stands rejected under 35 U.S.C. § 103(a) as unpatentable over
Choi I, Choi II, Pemet, Pangal, and Sawada.8
OPINION
Rejection I
“[T]he test for [compliance with the written description requirement]
is whether the disclosure of the application relied upon reasonably conveys
to those skilled in the art that the inventor had possession of the claimed
subject matter as of the filing date.” Ariad Pharms., Inc. v. Eli Lilly & Co.,
598 F.3d 1336, 1351 (Fed. Cir. 2010).
3 Final Act. 2-18; Ans. 2-18.
4 US 2008/0173350 Al, published July 24, 2008 (“Choi I”).
5 US 2009/0142878 Al, published June 4, 2009 (“Choi II”).
6 Pemet, P. et al., Growth of thin
ju-Si:H on intrinsic a-Si:Hfor
solar cells application, 452 Materials Research Society Symposium
- Proceedings, 1997, pp. 889-894.
7 Pangal, K., et al., Hydrogen plasma enhanced crystallization of
hydrogenated amorphous silicon films, 85 Journal of Applied Physics, 1999,
pp. 1900-1906.
8 US 2009/0165853 Al, published July 2, 2009 (“Sawada”).
3
Appeal 2016-002206
Application 13/161,081
The Examiner finds that the phrase, “wherein reliance on increasing
dopant concentration in the microcrystalline silicon to increase efficiency
and fill factor of the photovoltaic device is reduced by said increasing the
plasma treatment time within the range of from between 250 to about 500
seconds,” is not supported by the originally-filed Specification.9 Final Act.
3. Appellants argue that Figures 3 A and 3B of the Specification demonstrate
possession of the subject matter in dispute. App. Br. 11-12. Particularly,
Appellants contend that these Figures illustrate that both plasma treatment
and doping improves efficiency and fill-factor, but that plasma treatment
decreases the percentage of increased performance resulting from doping.
Id. 12-13. In other words, Appellants argue that the disputed claim
language requires that cell performance is enhanced to a greater extent by
increasing plasma treatment time than by increasing dopant concentration.
See Reply Br. 3 (“[T]he amount of the performance increase that is the result
of the increased dopant decrease [s] with increasing [plasma treatment]
time.”).
The problem with Appellants’ argument is two-fold. First, Figures 3A
and 3B lack sufficient information to support Appellants’ characterization of
what they show. With regard to the content of each Figure, the Specification
states that cell performance versus plasma treatment time is “illustratively
shown.” Spec. 42, 43. No data is provided. For example, whereas
Figure 3C identifies samples containing increasing doping concentrations
(indicated in the Figure as “x 4” and “x 8” doping), no information is given
9 Appellants added the quoted language to claim 1 by amendment during
prosecution. See Appellants’ Response Under 37 C.F.R. § 1.111, dated
December 29, 2014.
4
Appeal 2016-002206
Application 13/161,081
regarding doping concentration in connection with any of the cells
illustratively depicted in Figure 3 A or 3C. As such, it is impossible to
determine whether the different performance values graphically allocated to
doping in those Figures is attributable to different doping concentrations or
to plasma treatment time. Second, even if Figures 3A and 3B were
interpreted to show a decreased doping effect on performance, the claims
recite that “reliance on increasing dopant concentration” is reduced,
meaning that less dopant is used. Appellants fail to point to any part of the
Specification that demonstrates a decreased reliance on doping. To the
contrary, the Specification repeatedly states that doping is effective for
enhancing cell performance. See, e.g., Spec. ^ 31 (“To promote conductivity
of the tunnel junction 110, more doping may be provided in the region.”); id.
35 (“With the microcrystalline structure provided for tunnel junction layers
110 and 112, the active doping concentration can effectively be increased by
one or two orders of magnitude compared with a doping capacity of an
amorphous phase, thus increasing conductivity and overall cell efficiency.”);
id. 45 (“Overall, increased hydrogen plasma time and doping enhances fill
factor of tandem solar cells.”).
For the foregoing reasons, Appellants do not persuade us of error in
the Examiner’s finding of insufficient written description. Accordingly, we
sustain Rejection I.
Rejection II
The Examiner finds that the phrase, “wherein increasing plasma
treatment time increases efficiency and fill factor of the photovoltaic
device,” is indefinite because it is unclear whether that phrase refers to
increasing plasma treatment within the recited range of 250-500 seconds or
5
Appeal 2016-002206
Application 13/161,081
to increasing treatment time beyond 500 seconds. Appellants point out that
the claim expressly limits the treatment time to the above-mentioned range,
thereby resolving the purported ambiguity. App. Br. 15; Reply Br. 10-11.
We agree. Claim 1 expressly recites “a plasma treatment time ranging from
between about 250 to about 500 seconds” and that “increasing plasma
treatment time increases efficiency and fill factor.” We are persuaded that
the express language of claim 1, quoted above, sufficiently conveys that the
recited “increasing plasma treatment time” refers to increases within the
recited range of about 250 to about 500 seconds.
Rejection II is not sustained.
Rejection III
With regard to Rejection III, Appellants argue the claims as a group.
App. Br. 16-26. In accordance with 37 C.F.R. § 41.37(c)(l)(iv), we select
claim 1 as representative and decide the appeal based on the representative
claim alone.
Relevant to Appellants’ arguments on appeal, the Examiner finds that
Choi I discloses a process for fabricating a tandem silicon solar cell that
includes forming a microcrystalline silicon tunnel junction layer on a
deposited amorphous silicon layer, but that Choi I does not apply hydrogen
plasma treatment to the amorphous material. Final Act. 9. The Examiner
finds that Choi II teaches that hydrogen plasma treatment of an amorphous
layer improves formation of an overlying microcrystalline tunnel junction
layer by converting at least a portion of the amorphous silicon to
microcrystalline silicon, which acts as a seed layer. Id. at 10. The Examiner
finds that both Pemet and Pangal provide evidence that the time over which
amorphous silicon is subjected to hydrogen plasma treatment effects
6
Appeal 2016-002206
Application 13/161,081
conductivity (Pemet) and rate and depth of crystallization (Pangal), such that
plasma treatment time in Choi II would have been recognized as a result-
effective variable, the optimization of which would have been obvious to
one of ordinary skill in the art. Id. at 12-13. In light of the foregoing
findings, the Examiner concludes that it would have been obvious to subject
the amorphous silicon layer in Choi I to hydrogen plasma treatment for an
optimal exposure time, resulting in a method encompassed by Appellants’
claim 1. Id. at 13.
Appellants argue that “the applied references fail to teach or suggest
forming a layer of silicon seeds from an amorphous material of an intrinsic
semiconductor layer using a hydrogen plasma, and then using the layer of
silicon seeds for the growth site of a junction layer in a following deposition
step.” App. Br. 17. We disagree. As the Examiner points out (Final Act.
10), Choi II expressly teaches that the disclosed “plasma treatment helps to
convert at least a portion of the n-doped amorphous silicon layer into n-
doped microcrystalline silicon. This n-doped microcrystalline silicon acts as
a seed layer improving n-doped microcrystalline silicon deposition thereon.”
Choi II 31. Appellants’ separate argument that Choi II involves plasma
treatment of a doped amorphous layer rather than an undoped layer (App.
Br. 20) is unpersuasive. Claim 1 lacks any recitation that precludes doping
in the plasma treated layer.
Appellants also contend that Figures 3A and 3B of the Specification
demonstrate unexpected results obtained by conducting plasma treatment.
App. Br. 18-19. Particularly, Appellants argue that “the claimed treatment
process when applied for a time period ranging from 250 seconds to 500
7
Appeal 2016-002206
Application 13/161,081
seconds results in an unexpected increase in efficiency and fill factor of the
solar cell.” Id. at 18.
However, as noted in connection with Rejection I, the Specification
fails to present any data in connection with Figures 3A and 3B. Rather,
Appellants characterize these Figures as illustrative. Spec. 42 43.
Moreover, although these Figures depict schematically that cell performance
as reflected by efficiency and fill factor are increased as the plasma exposure
time is increased, Appellants do not point to any evidence to support that the
resulting enhancement would not have been expected. See In re Klosak, 455
F.2d 1077, 1080 (CCPA 1972) (“[I]t is not enough to show that results are
obtained which differ from those obtained in the prior art: that difference
must be shown to be an unexpected difference.”). Conversely, Choi II
acknowledges that plasma treatment enhances formation of the
microcrystalline layer, and that the microcrystalline layer improves cell
efficiency due to enhanced current collection. Choi II 32, 36. Appellants
acknowledge in the Specification that the observed increased efficiency and
fill factor correspond to an increased conductivity of the microcrystalline
layer (Spec. 35, 40), which Pemet teaches to be an expected consequence
to plasma treatment of the underlying amorphous material (Pemet 3). On
this record, the Appellants have not shown by a preponderance of the
evidence that unexpected results support a conclusion of nonobviousness.
Appellants argue that “Pemet fails to recognize the increased cell
efficiency and fill factor that can result from adjusting the time period for the
plasma treatment.” App. Br. 22. However, as noted, Appellants relate
efficiency and fill factor to conductivity. Spec. 35, 40. Pemet teaches
that for a given pressure and power applied in a plasma treatment operation,
8
Appeal 2016-002206
Application 13/161,081
the resulting conductivity of a deposited microcrystalline layer “depends on
the exposure time of the substrate to the Eh or CO2 plasma.” Pemet 3.
Moreover, Appellants fail to persuasively dispute the Examiner’s
determination that the combined teachings of Choi I, Choi II, and Pemet
suggest a process that applies substantially the same steps to substantially
the same materials, Final Act. 12, which supports a reasonable inference that
the resulting cell would have exhibited the same properties as claimed. See
In re Best, 562 F.2d 1252, 1255 (CCPA 1977) (“Where, as here, the claimed
and prior art products are identical or substantially identical, or are produced
by identical or substantially identical processes, the PTO can require an
applicant to prove that the prior art products do not necessarily or inherently
possess the characteristics of his claimed product.”).
Finally, Appellants argue that the cited prior art fails to teach the
particular plasma treatment times recited in claim 1. App. Br. 24-25.
Appellants argue that the Examiner does not address their contention that
plasma treatment time in the range of 250 to 500 seconds yields unexpected
results and, therefore, is critical. Id. This argument, however, fails to refute
the Examiner’s finding that the plasma treatment time would have been a
known result-effective variable, such that its optimization would have been
obvious to one of ordinary skill, because, as set forth above, Appellants
showing of unexpected results is unpersuasive. Pemet’s express teaching
that conductivities obtained for microcrystalline layers formed after plasma
treatment “depends on the exposure time of the substrate” such that, “for a
fixed set of parameters (pressure and power), an optimum in surface
treatment can be found,” (Pemet 3), further weighs against Appellants’
9
Appeal 2016-002206
Application 13/161,081
contention that the claimed exposure times exhibit a result that would have
been unexpected.
For the foregoing reasons, Appellants do not persuade us of reversible
error in the Examiner’s Rejection of claims 1—4, 6-8, and 26 under 35
U.S.C. § 103(a). Accordingly, Rejection III is sustained.
Rejection IV
Appellants fail to present any substantive argument against Rejection
IV beyond those arguments discussed above in connection with Rejection
III. See App. Br. 26-27. Accordingly, Rejection III also is sustained.
DECISION
The Examiner’s decision rejecting claims 1—4, 6-9, and 26 under 35
U.S.C. § 112, second paragraph, is reversed.
The Examiner’s decisions rejecting claims 1—4, 6-9, and 26 under 35
U.S.C. §§ 112, first paragraph, and 103(a) are 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).
AFFIRMED
10
