Ex Parte Birecki et al

Board of Patent Appeals and Interferences

Mar 27, 2009

10932695 (B.P.A.I. Mar. 27, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte HENRYK BIRECKI, VU THIEN BINH, SI-TY LAM,
HUEI PEI KUO, and STEVEN L. NABERHUIS
____________

Appeal 2009-1372
Application 10/932,695
Technology Center 2800
____________

Decided:1 March 27, 2009
____________

Before MAHSHID D. SAADAT, CARLA M. KRIVAK,
and KARL D. EASTHOM, Administrative Patent Judges.

SAADAT, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 9 and 12-14. Claims 1-8 and 15-31 have been canceled

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the decided date
shown on this page of the decision. The time period does not run from the
Mail Date (paper delivery) or Notification Date (electronic delivery).
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and claims 10 and 11 have been objected to as being dependent upon
rejected base claims, but otherwise indicated as allowable if rewritten in
independent form. We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

STATEMENT OF THE CASE
Appellants’ invention relates to a field emission device, which
includes an emitter electrode, an extractor electrode, and a solid-state field
controlled emitter that utilizes a Schottky metal-semiconductor junction or
barrier. The Schottky metal-semiconductor barrier is formed on the emitter
electrode and electrically coupled with the extractor electrode such that
when an electric potential is placed between the emitter electrode and the
extractor electrode, a field emission of electrons is generated from an
exposed surface of the semiconductor layer. (Spec. 3:24-32).
Independent Claim 9 is representative and reads as follows:
9. A process for fabricating electron emission devices,
comprising:

forming an emitter electrode layer;

forming an extracting electrode layer proximate the conductive
semiconductor layer;

forming an aperture through a portion of the extracting
electrode layer to expose a portion of the emitter electrode layer;

forming a Schottky metal layer on the emitter electrode layer
through the aperture; and

forming a conductive semiconductor layer on the Schottky
metal layer through the aperture to form a Schottky metal-
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semiconductor barrier between the metal layer and the conductive
semiconductor layer, thereby forming a solid-state field controlled
emitter.

The Examiner relies on the following prior art in rejecting the claims:
Christensen US 4,663,559 May 5, 1987
Birecki US 6,976,895 B2 Dec. 20, 2005

Claims 9 and 12-14 stand rejected under 35 U.S.C. § 102(b) as being
anticipated by Christensen.
Claims 9 and 12-14 stand rejected on the ground of non-statutory
obviousness-type double patenting as being unpatentable over claims 1-7 of
Birecki in view of Christensen.
Rather than repeat the arguments here, we make reference to the
Briefs (App. Br. filed Oct. 23, 2007; Reply Br. filed Mar. 26, 2008) and the
Answer (mailed Jan. 8, 2008) for the respective positions of Appellants and
the Examiner.

ISSUE
The issue is whether the Examiner erred in rejecting the claims under
35 U.S.C. § 102(b) and non-statutory obviousness-type double patenting.
The issue specifically turns on whether Christensen discloses an electron
emission device having a Schottky metal layer over the emitter electrode
forming a Schottky metal-semiconductor barrier between the metal layer and
a conductive semiconductor layer formed on the metal layer, as recited in
claim 9.

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FINDINGS OF FACT
1. Christensen relates to a cold field emission device wherein
insulator and conductor particles are deposited as a random mixture and
form the tip of a conical structure having a base formed of a conductive
material. The insulative and conductive materials forming the particles are
chosen such that the work function of the insulator is greater than the work
function of the conductor. That work function difference defines ohmic
contact between the materials. (Abstract; col. 2, ll. 51-59).
2. Christensen discloses that emission of electrons is produced by
imposing a field on a multiplicity of insulative particles in and of the surface
of a cermet. The particles are arranged in a random distribution of insulative
and conductive commingled particles. A cermet is particularly found at the
exposed top surface or tip of a pyramid or conic structure. (Col. 4, ll. 13-
19).
3. Christensen teaches that the body of the conic structure is
formed of conductive material while the last region forms the tip and is a
mix of insulative and conductive particles, all in ohmic contact with adjacent
particles. The work function of the insulative particles exceeds the work
function of the conductive particles to define an ohmic contact therebetween.
(Col. 4, ll. 24-35).
4. Christensen discloses that upon application of potential to the
electrodes of the field emission device, assuming the field is sufficient, the
electrons flow through the conductive particles and the ohmic contacts with
the insulative particles to initiate electron flow in the conduction band of the
insulative particles. The field acting upon the conductive particles
undergoes Schottky barrier lowering to enable continual and constant
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tunneling and flow of electrons from the metal through the conductive band
into vacuum. (Col. 4, l. 63 – col. 5, l. 4).
5. As shown in Figure 2 of Christensen, the bottom layer 41 of the
conic structure is a conductor layer made of the same material as conductive
particles 43 commingled in the cermet 42. (Col. 11, ll. 33-38).
6. Christensen further discloses that the conductive particles 43
are in ohmic contact with the insulative particles 44 having an initial deposit
biased in favor of conductive particles in ohmic contact with the bottom or
support layer 41. (Col. 11, ll. 49-56).
7. With further reference to Figure 2, Christensen discloses that
the base of the conic structure 41 is in ohmic contact with a conductor 31,
which is insulated from or formed upon an insulator substrate 28. (Col. 12,
ll. 16-18).

PRINCIPLES OF LAW
In rejecting claims under 35 U.S.C. § 102, “[a] single prior art
reference that discloses, either expressly or inherently, each limitation of a
claim invalidates that claim by anticipation.” Perricone v. Medicis Pharm.
Corp., 432 F.3d 1368, 1375 (Fed. Cir. 2005) (citing Minn. Mining & Mfg.
Co. v. Johnson & Johnson Orthopaedics, Inc., 976 F.2d 1559, 1565 (Fed.
Cir. 1992)). See also In re Paulsen, 30 F.3d 1475, 1478-79 (Fed. Cir. 1994).
“Anticipation of a patent claim requires a finding that the claim at issue
‘reads on’ a prior art reference.” Atlas Powder Co. v. IRECO, Inc., 190 F.3d
1342, 1346 (Fed. Cir. 1999) (quoting Titanium Metals Corp. of Am. v.
Banner, 778 F.2d 775, 781 (Fed. Cir. 1985)).

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ANALYSIS
Appellants argue that Christensen does not disclose the claimed
Schottky metal barrier between the metal layer formed on the emitter
electrode layer and the conductive semiconductor layer formed on the metal
layer (App. Br. 5). Appellants further assert that Christensen, in contrast
with the claimed Schottky barrier, discloses an ohmic contact between
cermet 42 and conductive layer 41 (App. Br. 5-6; Reply Br. 5). With respect
to the reference made to the “‘Schottky barrier lowering’” in Christensen,
Appellants argue that it is the barrier between the emitter and vacuum that is
lowered, and not the barrier between the conductive base 41 and the cermet
(App. Br. 6; Reply Br. 6).
The Examiner relies on the only reference made to a Schottky barrier
in Christensen, starting at column 4, line 63, and asserts (Ans. 6) that the
same barrier lowering between the conductive particles and the insulative
particles in the cermet layer must be between the cermet and base layer 41
(Ans. 7). The Examiner reasons that layer 41 is taught to be made of the
same conductive material as the material forming conductive particles 43 in
the cermet and therefore, a Schottky barrier is present between base layer 41
and insulative particles 44 in the cermet (id.).
Upon a review of Christensen, we disagree with the Examiner’s
characterization of the contact between base layer 41 and cermet layer 42 as
a Schottky barrier. Christensen repeatedly teaches that the contact between
the conductive conic structure 41 and the cermet layer 42 is an ohmic
contact (FF 3 and 5-7). Christensen further describes the cermet layer
formed over the tip of the conic structure as a random mixture of conductive
and insulative particles in ohmic contact with each other (FF 1 and 2).
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Therefore, the contact between layers 41 and 42, as shown in Figure 2 of
Christensen, is an ohmic contact.
As argued by Appellants (App. Br. 6; Reply Br. 6), the only reference
Christensen makes to a “Schottky barrier” is with respect to the behavior of
the conductive and insulative particles in the presence of an electric field (FF
4). The described Schottky barrier lowering enables continual and constant
tunneling and flow of electrons from the metal through the conductive band
into vacuum (id.). While Christensen explains how the conduction within
the cermet layer 42 takes place by tunneling between the conductive and
insulative particles and the applied electric field has a Schottky barrier
lowering effect (FF 4), the macroscopic nature of the contact between the
cermet layer and the metal layer forming the conic structure 41 is identified
as an ohmic contact. See also FF 6.

CONCLUSION
On the record before us, and in view of our analysis above, we find
that Christensen does not disclose an electron emission device having a
Schottky metal-semiconductor barrier between the metal layer formed on the
emitter electrode and a conductive semiconductor layer formed on the metal
layer, as recited in claim 9. Therefore, since Appellants have shown error in
the Examiner’s position that Christensen anticipates claim 9, we do not
sustain the 35 U.S.C. § 102 rejection of claims 9 and 12-14. Additionally,
for the same reasons, we do not sustain the obviousness-type double
patenting rejection of claims 9 and 12-14 as being unpatentable over claims
1-7 of Birecki in view of Christensen.

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Application 10/932,695

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ORDER
The decision of the Examiner rejecting claims 9 and 12-14 is reversed.

REVERSED

KIS

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