Ex Parte Frank

Patent Trial and Appeal Board

Jan 2, 2013

10283971 (P.T.A.B. Jan. 2, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte MICHAEL L. FRANK
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Appeal 2010-008541
Application 10/283,971
Technology Center 2800
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Before CARL W. WHITEHEAD, JR., ERIC S. FRAHM and
ANDREW J. DILLON, Administrative Patent Judges.

WHITEHEAD, JR., Administrative Patent Judge.

DECISION ON APPEAL
Appeal 2010-008541
Application 10/283,971

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STATEMENT OF THE CASE
Appellant is appealing claims 3 and 5. Appeal Brief 3. We have
jurisdiction under 35 U.S.C. § 6(b) (2012).
We reverse.

Introduction
The invention is directed resistors in gallium arsenide semiconductor
devices. Appeal Brief 3-4.

Illustrative Claims
3. A device comprising:
a resistor including:
a semi-insulating substrate;
an active layer, positioned over the semi-insulating
substrate, including an epitaxial layer designed for enhancement
mode operation;
a first channel region positioned over the active layer;
a first gate metal covering a portion of the first channel
region;
ohmic contact material positioned at opposing ends of the
active layer;
a second gate metal covering a portion of the first
channel region; and
metal positioned over the opposing ends of the active
layer to form input/output pads.

5. A device comprising:
a resistor including:
a semi-insulating substrate;
an active layer, positioned over the semi-insulating
substrate, including an epitaxial layer designed for enhancement
mode operation;

Appeal 2010-008541
Application 10/283,971

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a first channel region having a serpentine shape,
positioned over the active layer;
a first gate metal covering a portion of the first channel
region; ohmic contact material positioned at opposing ends of
the active layer;
a second gate metal covering a portion of the first
channel region; and
metal positioned over the opposing ends of the active
layer to form input/output pads.

Rejections on Appeal
Claim 3 stands rejected under 35 U.S.C. §103(a) as being
unpatentable over Sriram (U.S. Patent Number 6,906,350 B2; issued June
14, 2005, filed October 24, 2001), Schnabel (U.S. Patent Number 5,268,650;
issued December 7, 1993) and Yamashita (U.S. Patent Application
Publication Number: 2005/0017272 A1; published January 27, 2005,
Foreign Application Priority Data , JP 2001-366767, Nov. 30, 2001).
Answer 3-4.
Claim 5 stands rejected under 35 U.S.C. §103(a) as being
unpatentable over Sriram, Schnabel, Yamashita and Cheney (U.S. Patent
Number 3,731,164; issued May 1, 1973). Answer 5.

Issues on Appeal
Do Sriram, Schnabel and Yamashita, either alone or in combination,
disclose a semiconductor device having enhancement mode semiconductor
device as claimed?
Do Sriram, Schnabel, Yamashita and Cheney, either alone or in
combination, disclose a semiconductor device having enhancement mode
semiconductor device as claimed?
Appeal 2010-008541
Application 10/283,971

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ANALYSIS
Appellant argues that Sriram is deficient because it does not disclose
an “epitaxial layer designed for enhancement mode operation” as recited in
claim 3. Appeal Brief 6. The Examiner acknowledges Sriram’s deficiency
and relies upon the teachings of Yamashita to address it. Answer 4.
Appellant argues that Yamashita does not address Sriram’s deficiency
because there is no indication within Yamashita that the delta doped SiC
layer 41 is either epitaxial or designed for enhancement mode operation.
Appeal Brief 7.
The Examiner finds that because Sriram discloses an epitaxial delta
doped active layer 14, Yamashita was cited to show that a delta doped SiC
layer can used in an enhancement mode transistor operation and together,
Sriram and Yamashita discloses that an epitaxial delta doped SiC layer can
be used in an enhancement mode transistor operation. Answer 6. The
employment of epitaxial layers are well known in the art and it is evident by
Appellant’s own Specification that growing the enhancement mode layer as
opposed to forming it via a deposition method is not critical to the
invention’s novelty. See Specification [0017].
However, we do not agree with the Examiner’s findings and we find
Appellant’s argument that there is no motivation to combine the references
because the combination of references would not disclose the claimed
resistor to be persuasive. Appeal Brief 7. Sriram discloses a MESFET
(metal semiconductor field effect transistor) which is a depletion mode
transistor because of its ability to control the channel by varying the
depletion layer under the metal contact. See Sriram’s Figure 1. Therefore
Appeal 2010-008541
Application 10/283,971

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there is no reason to modify Sriram’s active layer 14 in the manner in which
the Examiner’s proposes by including an enhancement mode layer which is
counter intuitive to Sriram’s basic operation. Schnabel does not address
Sriram’s deficiency. Therefore we do not sustain the Examiner’s rejection
of claim 3.
We do not sustain the Examiner’s rejection of claim 5, having
limitations commensurate in scope with claim 3, for the same reasons as
stated above because Cheney does not address the noted deficiency of the
combination of Sriram, Yamashita and Schnabel.

DECISION
The rejections of claims 3 and 5 are reversed.

REVERSED

Vsh