Ex parte GORONKIN et al.

Board of Patent Appeals and Interferences

Oct 2, 1998

08297279 (B.P.A.I. Oct. 2, 1998)

Application for patent filed August 29, 1994.1
1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1)
was not written for publication in a law journal and (2) is not
binding precedent of the Board.
Paper No. 16
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte HERBERT GORONKIN
SAIED N. TEHRANI and
JUN SHEN
_____________
Appeal No. 96-1512
Application 08/297,2791
______________
ON BRIEF
_______________
Before URYNOWICZ, KRASS and JERRY SMITH, Administrative Patent
Judges.
JERRY SMITH, Administrative Patent Judge.
DECISION ON APPEAL
Appeal No. 96-1512
Application 08/297,279
2
This is a decision on the appeal under 35 U.S.C. § 134
from the examiner’s rejection of claims 1-22, which constitute
all the claims in the application.
The disclosed invention pertains to a complementary
heterojunction semiconductor device. More specifically, the
invention is directed to the interconnection of first and second
resonant interband tunneling transistors (RITTs). The gates of
the first and second RITTs are made from different semiconductor
materials. The first gate material has a valence band having an
energy greater than a conduction band of the second gate
material.
Representative claim 1 is reproduced as follows:
1. A complementary heterojunction semiconductor device,
comprising:
a first resonant interband tunneling transistor having a
first gate of a first compound semiconductor type, a drain
coupled to said first gate, and a common output coupled to said
first gate; and
a second resonant interband tunneling transistor having a
second gate of a second compound semiconductor type, said second
gate coupled to said common output, and a source coupled to said
second gate, wherein said first compound semiconductor type has a
valence band having an energy greater than a conduction band of
said second compound semiconductor type when said complementary
heterojunction semiconductor device is in an unbiased state.
The examiner relies on the following references:
Aoki et al. (Aoki) 4,768,076 Aug. 30, 1988
Söderström et al. (Söderström) 5,113,231 May 12, 1992
Appeal No. 96-1512
Application 08/297,279
3
Zhu et al. (Zhu) 5,142,349 Aug. 25, 1992
Claims 1-22 stand rejected under 35 U.S.C. § 103. As
evidence of obviousness the examiner offers the collective
teachings of Zhu, Söderström and Aoki.
Rather than repeat the arguments of appellants or the
examiner, we make reference to the brief and the answer for the
respective details thereof.
OPINION
We have carefully considered the subject matter on
appeal, the rejection advanced by the examiner and the evidence
of obviousness relied upon by the examiner as support for the
rejection. We have, likewise, reviewed and taken into
consideration, in reaching our decision, the appellants’
arguments set forth in the brief along with the examiner’s
rationale in support of the rejection and arguments in rebuttal
set forth in the examiner’s answer.
It is our view, after consideration of the record before
us, that the evidence relied upon and the level of skill in the
particular art would not have suggested to one of ordinary skill
in the art the obviousness of the invention as set forth in
claims 1-22. Accordingly, we reverse.
Appeal No. 96-1512
Application 08/297,279
4
We consider first the rejection of independent claim 1
under 35 U.S.C. § 103 as being unpatentable over the collective
teachings of Zhu, Söderström and Aoki. In rejecting claims under
35 U.S.C. § 103, it is incumbent upon the examiner to establish a
factual basis to support the legal conclusion of obviousness.
See In re Fine, 837 F.2d 1071, 1073, 5 USPQ2d 1596, 1598 (Fed.
Cir. 1988). In so doing, the examiner is expected to make the
factual determinations set forth in Graham v. John Deere Co., 383
U.S. 1, 17, 148 USPQ 459, 467 (1966), and to provide a reason why
one having ordinary skill in the pertinent art would have been
led to modify the prior art or to combine prior art references to
arrive at the claimed invention. Such reason must stem from some
teaching, suggestion or implication in the prior art as a whole
or knowledge generally available to one having ordinary skill in
the art. Uniroyal Inc. v. Rudkin-Wiley Corp., 837 F.2d 1044,
1051, 5 USPQ2d 1434, 1438 (Fed. Cir.), cert. denied, 488 U.S. 825
(1988); Ashland Oil, Inc. v. Delta Resins & Refractories, Inc.,
776 F.2d 281, 293, 227 USPQ 657, 664 (Fed. Cir. 1985), cert.
denied, 475 U.S. 1017 (1986); ACS Hospital Systems, Inc. v.
Montefiore Hospital, 732 F.2d 1572, 1577, 221 USPQ 929, 933 (Fed.
Cir. 1984). These showings by the examiner are an essential part
of complying with the burden of presenting a prima facie case of
Appeal No. 96-1512
Application 08/297,279
5
obviousness. Note In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ2d
1443, 1444 (Fed. Cir. 1992).
Zhu is directed to a complementary heterojunction field
effect transistor (HFET). The Zhu HFET is designed to have a P-
channel quantum well and an N-channel quantum well separated by a
barrier layer. Zhu teaches that "[t]he particular materials for
P-channel quantum well 12 and N-channel quantum well 14 are
chosen because P-channel quantum well 12 must have a valence band
energy greater than conduction band energy of N-channel quantum
well 14" [column 3, lines 6-10]. The examiner relies on this
relationship between the P-channel and the N-channel materials in
Zhu to meet the similar relationship of the gate materials
recited in claim 1.
Söderström is directed to a resonant interband tunneling
device in which the lateral layers of compound semiconductor
material and barrier layers are shown [Figures 16 and 19]. The
examiner states that "[t]he variation of embodiments as shown by
Soderstrom in combination with Zhu’s more general structure would
have been obvious to a skilled artisan in order to achieve proper
integration" [answer, page 3]. The examiner does not further
elaborate on this point. Aoki is cited to show the connection of
transistors and biases to implement an inverter operation.
Appeal No. 96-1512
Application 08/297,279
6
Appellants argue that the collective teachings of the
applied prior art do not support the examiner’s conclusion.
Specifically, appellants argue that claim 1 is directed to the
interconnection of two RITTs having a specific relationship
between the gate materials and that none of the applied
references suggests the interconnection as specifically recited
in claim 1 [brief, pages 3-5].
Based upon the evidence of record provided in this case,
we agree with appellants that the examiner’s conclusion of
obviousness has not been properly established. The examiner has
essentially equated the relationship between Zhu’s P-channel and
N-channel materials with the claimed relationship between the
gate materials of a first and second RITT as recited in claim 1.
The applied prior art only establishes that it was known that
different compound semiconductor materials had different energy
bands which would permit tunneling to occur in a semiconductor
device. This prior art, however, does not suggest that two RITTs
should be interconnected as recited in claim 1 with the gate
materials as specifically claimed. We do not agree with the
examiner’s finding that the FET teachings of Zhu are teachings of
the interconnection of two RITTs [answer, page 5].
Appeal No. 96-1512
Application 08/297,279
7
For all the reasons discussed above, we do not sustain
the rejection of independent claim 1 based on the evidence of
record in this case. Accordingly, we also do not sustain the
rejection of dependent claims 2-15. Since independent claim 21
is similar in scope to claim 1, we do not sustain the rejection
of claim 21 or dependent claim 22.
Independent claim 16 recites the specific interconnection
of layers between a first heterojunction transistor and a second
heterojunction transistor. Appellants argue that the examiner
has failed to establish a prima facie case of obviousness for the
structure specifically recited in claim 16 [brief, pages 5-6].
We agree. The examiner has not indicated how each of the
recitations of independent claim 16 is suggested by the teachings
of the applied prior art. The examiner’s conclusion of
obviousness must be supported by appropriate factual findings
which have not been made here. Therefore, we do not sustain the
rejection of independent claim 16 or dependent claims 17-20.
In conclusion, we have not sustained the examiner’s
rejection of any of the claims under 35 U.S.C. § 103. Therefore,
the decision of the examiner rejecting claims 1-22 is reversed.
REVERSED
Appeal No. 96-1512
Application 08/297,279
8
)
STANLEY M. URYNOWICZ, JR. )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
ERROL A. KRASS )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
JERRY SMITH )
Administrative Patent Judge )
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