Ex parte Freeouf

Board of Patent Appeals and Interferences

Apr 20, 2000

08179601 (B.P.A.I. Apr. 20, 2000)

1
Paper No. 22
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(2) is not binding precedent of the Board.
UNITED STATES PATENT AND TRADEMARK OFFICE
_______________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_______________
Ex parte JOHN L. FREEOUF
______________
Appeal No. 1997-1249
Application 08/179,601
_______________
ON BRIEF
_______________
Before FLEMING, RUGGIERO and HECKER, Administrative Patent
Judges.
HECKER, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 2 through 4, 11 through 14, 16 through 20 and 22
through 27, Paper No. 10, mailed November 22, 1995 (claims 1,
5 through 10 and 15 had been canceled). Although claim 21 had
been rejected in a previous rejection (Paper No. 8), no
Appeal No. 1997-1249
Application 08/179,601
2
indication of its status appears in Paper No. 10. However,
the status of claim 21 is moot since it was canceled by an
entered amendment after final rejection, Paper No. 12,
received February 12, 1996, which paper also canceled claims
14, 16 through 20 and 22 through 26. This amendment (Paper
No. 12) also added new claims 28 through 32, and amended claim
27. As a result of the amendment of Paper No. 12, claims 2
through 4, 11 through 13 and 28 through 32 stand finally
rejected and claim 27 stands allowable as recited in the
Examiner’s Advisory Action, Paper No. 13, mailed March 14,
1996. The invention relates to a radiation detector
made of solid state materials. In particular, noting Figure
1, the detector (3) is made up of a stack of absorption
members (4) where each member is an intrinsic (i) layer (6,8)
(of high density, high band gap semi-conductor) with a
relatively thin high conductivity layer p (7) or n (5,9) layer
(or a metal), that covers each entire face of the i layer and
with a bias across each i layer via a pair of the p/n or metal
layers.
Representative independent claim 28 is reproduced as
follows:
Appeal No. 1997-1249
Application 08/179,601
3
28. A radiation detector comprising:
a plurality of planar absorption members arranged in a
stack having a surface made up of the edges of said absorption
members,
each said absorption member having at least one
terminating edge exposed in a surface of said stack,
each said absorption member further having a center layer
of high density, high band gap, semiconductor material that is
intrinsic, and has a selected thickness dimension,
a first highly conductive contacting layer of only one of
a high extrinsic conductivity semiconductor material and a
metal,
said first contacting layer being contiguous with a first
surface of said intrinsic layer, coextensive with said
intrinsic layer, and having a thickness that is small relative
to said selected thickness of said intrinsic layer, and,
a second highly conductive contacting layer of only one
of a high extrinsic conductivity semiconductor material and a
metal,
said second contacting layer being contiguous with a
second and opposite surface of said intrinsic layer,
coextensive with said intrinsic layer, and has a thickness
that is small relative to said selected thickness of said
intrinsic layer, and,
an electrical bias applied between said first and said
second contacting layers, in a magnitude related to said
bandgap, the carrier density and said thickness dimension of
said intrinsic layer, of a magnitude sufficient for
essentially full charge extraction.
The Examiner relies on the following references:
Appeal No. 1997-1249
Application 08/179,601
From the language of the claims, it appears that this rejection is directed to claim 4 instead of1
claim 11.
4
Capasso 4,486,765 Dec. 4, 1984
Doehler et al. (Doehler) 4,839,714 Jun. 13,
1989
Danos 4,891,521 Jan. 2, 1990
Yamazaki et al.(Yamazaki) 4,917,474 Apr. 17, 1990
Biefeld et al. (Biefeld) 4,947,223 Aug.
7, 1990

Claims 2 through 4, 13 and 28 through 32 stand rejected
under 35 U.S.C. § 103 as being unpatentable over Capasso,
Biefeld, Doehler and Yamazaki, considered together.
Claims 11 and 12 stand rejected under 35 U.S.C. § 103 as1
being unpatentable over Capasso, Biefeld, Doehler and
Yamazaki, and further in view of Danos.
Rather than reiterate the arguments of Appellant and the
Examiner, reference is made to the brief, reply brief and
answer for the respective details thereof.
OPINION
After a careful review of the evidence before us, we will
not sustain the rejection of claims 2 through 4, 11 through 13
and 28 through 32 under 35 U.S.C. § 103.
The Examiner has failed to set forth a prima facie case.
It is the burden of the Examiner to establish why one having
Appeal No. 1997-1249
Application 08/179,601
5
ordinary skill in the art would have been led to the claimed
invention by the reasonable teachings or suggestions found in
the prior art, or by a reasonable inference to the artisan
contained in such teachings or suggestions. In re Sernaker,
702 F.2d 989, 995, 217 USPQ 1, 6 (Fed. Cir. 1983).
"Additionally, when determining obviousness, the claimed
invention should be considered as a whole; there is no legally
recognizable 'heart' of the invention." Para-Ordnance Mfg. v.
SGS Importers Int’l., 73 F.3d 1085, 1087, 37 USPQ2d 1237, 1239
(Fed. Cir. 1995) (citing W. L. Gore & Assocs. v. Garlock,
Inc., 721 F.2d 1540, 1548,
220 USPQ 303, 309 (Fed. Cir. 1983), cert. denied, 469 U.S. 851
(1984)).
With regard to the rejection of claims 28 and 31, grouped
together by both the Examiner (answer-page 5) and Appellant
(brief-page 6), the Examiner reasons that Doehler teaches a
photodetector with the claimed layered structure (Figures 3A
and 3B), except that the intrinsic (i) layers are shown as the
same thickness as the n and p layers. The Examiner then cites
Yamazaki for its photodetector with n and p layers thinner
Appeal No. 1997-1249
Application 08/179,601
6
than the i layer. Thus, the Examiner states, it would have
been obvious to make the i layers of Doehler thicker than its
n and p layers, as taught by Yamazaki, “to increase the volume
of i-type material available to absorb light, in order to
increase the sensitivity of the device to incident light.”
(Answer-page 3.)
Appellant argues that there is no motivation for the
combination of references (brief-page 8). We agree. The
Examiner’s reasoning that increasing the volume of the i layer
will increase detector sensitivity is not supported by
Yamazaki, and without more, is mere speculation. Also, an
increase in volume could be achieved by increasing the area
without increasing the thickness. In addition, even if
Yamazaki taught increased sensitivity with increased i layer
thickness, we see no reason to use this teaching in Doehler.
The i layer of Doehler does not contribute to sensitivity.
Doehler states at column 1 lines 42-66:
A doping superlattice consists of an alternating
sequence of n and p doped layers in a semiconductor.
These doped layers may, but need not, be separated
by layers of undoped (intrinsic) semiconductor
material. The doping superlattice is also referred
to as a NIPI superlattice because of the alternating
Appeal No. 1997-1249
Application 08/179,601
7
n-doped, intrinsic, p-doped and intrinsic layers in
such a superlattice.
The recombination of electrons from the n-type
layers with holes from the p-type layers results in
a periodic charge variation in the superlattice that
produces a periodic variation in the bottom of the
conduction band and in the top of the valence band,
thereby producing a periodic array of potential
wells as in a compositional superlattice. This also
results in a separation between the holes and the
electrons so that the recombination time for excess
holes and electrons is greatly increased. When
excited optically or electrically, a large number of
excess holes and electrons are created that flatten
the periodic potential and increase the effective
band gap (defined as the distance between a minimum
in the bottom of the conduction band and a maximum
in the top of the valence band) of the superlattice.
Therefore, the electrical and optical properties can
be varied by varying the number of excess holes and
electrons in the superlattice. (Emphasis added.)
Thus, the i layer of Doehler is not required, and does
not contribute to its optical properties. Therefore,
increasing the thickness of the i layer would not increase
sensitivity in Doehler, even if it would have increased
sensitivity in Yamazaki.
The Federal Circuit states that "[t]he mere fact that the
prior art may be modified in the manner suggested by the
Examiner does not make the modification obvious unless the
prior art suggested the desirability of the modification." In
Appeal No. 1997-1249
Application 08/179,601
8
re Fritch, 972 F.2d 1260, 1266 n.14, 23 USPQ2d 1780, 1783-84
n.14 (Fed. Cir. 1992), citing In re Gordon, 733 F.2d 900, 902,
221 USPQ 1125, 1127 (Fed. Cir. 1984). "Obviousness may not be
established using hindsight or in view of the teachings or
suggestions of the inventor." Para-Ordnance Mfg. v. SGS
Importers Int’l., 73 F.3d at 1087, 37 USPQ2d at 1239, citing
W. L. Gore & Assocs. v. Garlock, Inc., 721 F.2d at 1551, 1553,
220 USPQ at 311, 312-13.
The Examiner cites Biefeld (Figures 5 and 6), Doehler
(Figure 4) and Capasso (Figure 1) as redundantly teaching
“contacts” (answer-page 4). However, Appellant’s disclosed
contacts are not even recited in the claims.
Appellant notes that Danos “is the one reference directed
to general radiation detection.” (Brief-page 12.) Appellant
contends that his claims distinguish over Danos “by the fact
that the conductive layers [of Appellant] are coextensive with
the intrinsic region so as to extend to the edge . . . . In
Danos in contrast, the conductive layers 5 in Fig. 2, are
neither coextensive nor do they extend to the edges.” (Brief-
pages 12 and 13.) However, we note that in Figure 2 (as well
Appeal No. 1997-1249
Application 08/179,601
We note that claims 2 and 3 recite “said at least one absorption member(s)”, and claim 42
(continued...)
9
as Figure 1), Danos is not “coextensive” with the layers
because region C is reserved for an integrated circuit with a
buffer and amplifier (column 2, lines 62-64). An alternate
arrangement of Figure 3 places the integrated circuit in a
separate chip 18, off the detector region. Thus, in Figure 3
of Danos, the layers are “coextensive” (column 3, lines 34+).
However, Danos also lacks the claimed limitation of making the
p and n layers (or metal layers 5) thinner than the i layer.
Since there is no evidence in the record that the prior
art suggested the desirability of a radiation detector with a
p-i-n structure and the p and n layers “having a thickness
that is small relative to said selected thickness of said
intrinsic layer” as claimed in both independent claims 28 and
31, we will not sustain the Examiner’s rejection of these
claims.
The remaining claims on appeal also contain the above
limitations discussed in regard to claims 28 and 31 and
thereby, we will not sustain the rejection as to these
claims.2
Appeal No. 1997-1249
Application 08/179,601
(...continued)2
recites “said at least one intrinsic layer”. This language should be corrected to be consistent with the
new independent claim from which they depend.
10
We have not sustained the rejection of claims 2 through
4, 11 through 13 and 28 through 32 under 35 U.S.C. § 103.
Accordingly, the Examiner's decision is reversed.
REVERSED
Michael R. Fleming )
Administrative Patent Judge )
)
)
)
Joseph F. Ruggiero ) BOARD OF
PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
Stuart N. Hecker )
Administrative Patent Judge )

SNH/cam
Appeal No. 1997-1249
Application 08/179,601
11
Alvin J. Riddles
Box 34 Candlewood Isle
New Fairfield, CT 06812