Ex parte Ehmke

Board of Patent Appeals and Interferences

Aug 22, 2000

08595901 (B.P.A.I. Aug. 22, 2000)

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(2) is not binding precedent of the Board.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 JOHN C. EHMKE
_____________

Appeal No. 1997-3443
Application No. 08/595,901
______________

ON BRIEF
_______________

Before URYNOWICZ, THOMAS, and KRASS, Administrative Patent Judges

DECISION ON APPEAL

This appeal is from the final rejection of claims 13-16, 19-22 and 25-28.
The invention pertains to infrared focal plane photodiode arrays. Claim 13 is illustrative
and reads as follows:
13. A diode comprising:

(a) a substrate of p-type group II-VI semiconductor material
having a crystal lattice structure;

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Application No. 08/595,901

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(b) an electrically conductive material extending into said lattice
structure, said electrically conductive material forming an ohmic
contact with said substrate and damaging said lattice structure by
extending into said lattice structure to provide by said damage an
n-type region in said substrate in said damaged lattice region and
in a regions [sic] adjacent to and intimate with said electrically
conductive material within said lattice structure; and

(c) an electrical contact to the p-type substrate.

The references relied upon by the examiner as evidence of obviousness are:
Wotherspoon 4,411,732 Oct. 25, 1983
Baker 4,521,798 Jun. 04, 1985
Mc Adoo et al. (Mc Adoo) 5,451,769 Sep. 19, 1995
Claims 13, 14, 19, 20, 25 and 26 stand rejected under 35 U.S.C. § 102(b) as being
anticipated by Baker.
Claims 13-16, 19-22 and 25-28 are rejected under 35 U.S.C. § 103 as being unpatentable
over Baker in view of Mc Adoo.
The respective positions of the examiner and the appellant with regard to the propriety of
these rejections are set forth in the final rejection (Paper No. 7) and the examiner’s answer and
supplemental answer (Paper Nos. 11 and 13, respectively) and the appellant’s brief and reply
briefs (Paper Nos. 10, 12 and 14, respectively).
Appellant’s Invention
As noted in the examiner’s answer, the summary of the invention contained in the
brief is correct. Reference is made to that summary.

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The Prior Art
Baker illustrates in Figures 1-6 an array of photovoltaic radiation detector elements 10
formed in a p-type substrate 14 of infrared-sensitive material (cadmium mercury telluride,
HgCdTe) having a crystal lattice structure. Electrically conductive material 23 extends into the
lattice structure. N-type regions 13b are formed by ion etching of the structure so as to form
diodes having p-n junctions 12. Electrical contacts 24 are connected to the p-type substrate 14.
The above array is mounted on a substrate 1 comprising circuit elements for processing signals
derived from the array. Substrate 1 includes conductive elements 2, 3.
Mc Adoo discloses a photodetector. At column 3, lines 30-44, it is disclosed that
tungsten is used for electrically contacting HgCdTe.
Opinion
After consideration of the positions and arguments presented by both the examiner and
the appellants, we have concluded that the rejections should be sustained. We agree in general
with the comments made by the examiner; we add the following discussion for emphasis.
With respect to the rejection of claims 13, 14, 19, 20, 25 and 26 under 35 U.S.C. § 102(b) as
being anticipated by Baker, electrically conductive material 23 extends into the lattice structure
of the substrate 13b, 14 and forms an ohmic contact with the substrate. Material 23 clearly
provides the ohmic contact to connect the n-type side wall regions 13b to conductor elements 2
and 3. See column 10, lines 6-10. Thus, no merit exists in appellant’s position that Baker does
not disclose an electrically conductive material which extends into the lattice structure of the
substrate and forms an ohmic contact with the substrate.

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Appellant argues that Baker does not teach or suggest electrically conductive material
damaging the lattice structure by extending into said lattice structure. This is a process limitation
which is entitled to no patentable weight in appellant’s apparatus claim. Appellant has
effectively admitted that process limitations in product claims are entitled to no weight at page 2
of his reply brief filed July 8, 1997 (Paper No. 14) wherein he states,
[h]owever, after correctly stating that “a ’product by process’ claim is directed to
the product per se”, the Examiner then erroneously implies that the end product is
the same as in Baker.

Furthermore, when the prior art discloses a product which reasonably appears to be either
identical with or only slightly different than a product claimed in a product-by-process claim, a
rejection based alternatively on either section 102 or section 103 of the statute is eminently fair
and acceptable. In re Brown, 459 F.2d 531, 535, 173 USPQ 685, 688 (CCPA 1972).
To the extent that appellant is arguing that Baker does not disclose damaged regions, his
position is unpersuasive. The n-type regions 13b of Baker are damaged regions of the lattice
structure and they are adjacent to the electrically conductive material 23. The damage occurs
during manufacture when the n-type regions are formed from p-type regions by ion
bombardment.
Appellant’s attack on the examiner’s reference to U.S. Patent 4,411,732 to Wotherspoon
in his answer is of no import because the reference is unnecessary to the rejection1. The
examiner merely notes that Wotherspoon details the conversion of p-type cadmium mercury

1 Wotherspoon is specifically incorporated by reference in Baker

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telluride (CdHgTe) to n-type material by way of ion implantation/etching so as to cause damage
in the p-type CdHgTe material. At column 9, lines 29-35, Baker has a teaching to the same
effect.
With respect to the rejection of claims 13-16, 19-22 and 25-28 as obvious over Baker and
Mc Adoo under 35 U.S.C. § 103, appellant does not argue against the obviousness of combining
the teachings thereof, but merely asserts the same alleged deficiencies of Baker. Because we
have found no such deficiencies in Baker, we will sustain the obviousness rejection of these
claims.
No time period for taking any subsequent action in connection with this appeal may be
extended under 37 CFR § 1.136(a).
AFFIRMED

STANLEY M. URYNOWICZ, JR. )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JAMES D. THOMAS ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
ERROL A. KRASS )
Administrative Patent Judge )

vsh

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Application No. 08/595,901

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Rene’ E. Grossman
Texas Instruments Incorporated
P.O. Box 655474 MS 219
Dallas, TX 75265