Ex Parte Komada

Patent Trial and Appeal Board

Mar 10, 2014

12073215 (P.T.A.B. Mar. 10, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
_________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte SATOSHI KOMADA
__________

Appeal 2011-009218
Application 12/073,215
Technology Center 2800
___________

Before ADRIENE LEPIANE HANLON, CATHERINE Q. TIMM, and
JAMES C. HOUSEL, Administrative Patent Judges.

HANLON, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2011-009218
Application 12/073,215

2

A. STATEMENT OF THE CASE
The Appellant appeals under 35 U.S.C. § 134 from the final rejection
of claims 1-6. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
Claims 1, 2, and 6 are representative of the subject matter on appeal
and are reproduced below from the Claims Appendix of the Appeal Brief
dated August 6, 2010 (“App. Br.”).
1. A nitride semiconductor light emitting device
comprising:
a substrate;
a first n-type nitride semiconductor layer;
a light emitting layer;
a p-type nitride semiconductor layer;
a p-type nitride semiconductor tunnel junction layer;
an n-type nitride semiconductor tunnel junction layer;
and a second n-type semiconductor layer;
formed on the substrate in this order;
wherein said p-type nitride semiconductor tunnel
junction layer contacts said n-type nitride semiconductor tunnel
junction layer to form a tunnel junction,
said p-type nitride semiconductor tunnel junction layer
and said n-type nitride semiconductor tunnel junction layer
contain In,
said p-type nitride semiconductor tunnel junction layer
contacts said p-type nitride semiconductor layer, said p-type
nitride semiconductor layer having a larger band gap energy
than said p-type nitride semiconductor tunnel junction layer,
and
Appeal 2011-009218
Application 12/073,215

3

said n-type nitride semiconductor tunnel junction layer
contacts said second n-type nitride semiconductor layer, said
second n-type nitride semiconductor layer having a larger band
gap energy than said n-type nitride semiconductor tunnel
junction layer,
a shortest distance between an interface of said p-type
nitride semiconductor tunnel junction layer and said p-type
nitride semiconductor layer and an interface of said p-type
nitride semiconductor tunnel junction layer and said n-type
nitride semiconductor tunnel junction layer is greater than 2 nm
but less than 10 nm,
a shortest distance between an interface of said n-type
nitride semiconductor tunnel junction layer and said second n-
type nitride semiconductor layer and an interface of said p-type
nitride semiconductor tunnel junction layer and said n-type
nitride semiconductor tunnel junction layer is less than 40 nm.
2. The nitride semiconductor light emitting device
according to Claim 1, wherein the ratio of the number of In
atoms to the total number of Al, Ga, and In atoms in said p-type
nitride semiconductor tunnel junction layer is larger than 0.1.
6. The nitride semiconductor light emitting device
according to Claim 1, wherein the ratio of the number of In
atoms to the total number of Al, Ga, and In atoms in said n-type
nitride semiconductor tunnel junction layer is larger than 0.1.
Claims 1-6 stand rejected under 35 U.S.C. § 103(a) as unpatentable
over Kneissl.1
B. DISCUSSION
1. Claim 1

1 US 2003/0116767 A1, published June 26, 2003.
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Appeal 2011-009218
Application 12/073,215

5

semiconductor tunnel junction layer (5) is greater than 2 nm but less than 10
nm.
The Examiner finds:
Kneissl discloses a shortest distance between an interface
of said p-type nitride semiconductor tunnel junction layer 216
and said p-type nitride semiconductor layer 214 and an
interface of said p-type nitride semiconductor tunnel junction
layer 216 and said n-type nitride semiconductor tunnel junction
layer 218 is typically around 20nm [0039-0040].
Ans. 5.
More specifically, Kneissl discloses that the thickness of the p-type
nitride semiconductor tunnel junction layer 216 “has a thickness between 10
nm and 100 nm and typically around 20 nm.” Kneissl, para. [0039]. The
Examiner concludes that it would have been obvious to one of ordinary skill
in the art to decrease this thickness to a value within the claimed range “in
order to reduce the operating voltage.” Ans. 5.
The Appellant argues:
Kneissl neither discloses nor suggests reducing the operating
voltage by reducing the thickness of the tunnel junction layer
216. Rather, Kneissl explicitly teaches that a “lower bandgap
Egap of the InGaN layer” and a “larger total electric field across
the tunnel junction would reduce the operating voltage”. . . .
App. Br. 12.
Kneissl discloses:
[T]he first part of the tunnel junction can be formed from highly
p-type doped InGaN:Mg or InGaAlN:Mg. The tunnel
probability increases exponentially with decreasing tunnel
junction bandgap [~exp(-Egap1.5)] and therefore the lower
Appeal 2011-009218
Application 12/073,215

6

bandgap Egap of the InGaN layer would reduce the operating
voltage. In addition, the large polarization fields present in
pseudomorphicaly strained InGaN films would add to the built-
in field of the pn-junction and consequently increase the total
electric field across the tunnel junction. As the tunnel
probability increases exponentially with increasing tunnel
junction field F [~exp(-1/F)], the larger total electric field
across the tunnel junction would reduce the operating voltage.
Kneissl, para. [0039] (emphasis added).
Relying on an article by T. Gessmann, et al.,2 the Examiner finds that
tunneling probability also increases exponentially upon decreasing layer
thickness. Ans. 8-9. Thus, the Examiner finds the motivation provided for
decreasing the tunnel layer thickness in Kneissl (i.e., to reduce the operating
voltage) is not based on impermissible hindsight but rather is supported by
the evidence of record. Ans. 9. The Appellant does not offer a response.
Moreover, relying on In re Aller, 220 F.2d 454, 456 (CCPA 1955), the
Examiner points out that “where the general conditions of a claim are
disclosed in the prior art, discovering the optimum or workable ranges
involves only routine skill in the art.” Ans. 5. In this regard, we find
Kneissl expressly discloses a thickness range “between 10 nm and 100 nm”
and would have taught one of ordinary skill in the art that a thickness at the
lower end of this range, e.g., 10.1 nm, would have been workable in
Kneissl’s device. See Kneissl, para. [0039].
As stated in In re Peterson, 315 F.3d 1325, 1329 (Fed. Cir. 2003):

2 T. Gessmann, et al., Ohmic contacts to p-type GaN mediated by
polarization fields in thin InxGa1-xN capping layers, 80 APPLIED PHYSICS
LETTERS 986, 988 (2002).
Appeal 2011-009218
Application 12/073,215

7

[A] prima facie case of obviousness exists when the claimed
range and the prior art range do not overlap but are close
enough such that one skilled in the art would have expected
them to have the same properties. Titanium Metals Corp. v.
Banner, 778 F.2d 775, 783 (Fed. Cir. 1985).
We find that the lower limit of Kneissl’s range and the upper limit of
the claimed range (i.e., “less than 10 nm”) are close enough that one of
ordinary skill in the art would have expected the claimed p-type nitride
semiconductor tunnel junction layer (5) and the p-type nitride semiconductor
tunnel junction layer disclosed in Kneissl (216) to have the same properties.
The Appellant has failed to establish reversible error in the
Examiner’s conclusion of obviousness. Therefore, the § 103(a) rejection of
claims 1 and 3-5 is sustained.3
2. Claims 2 and 6
The Examiner finds Kneissl discloses that the ratio of the number of
In atoms to the total number of Al, Ga, and In atoms in the p- and n-type
nitride semiconductor tunnel junction layers is larger than 0.1 as recited in
claims 2 and 6, respectively. Ans. 6, 7. For support, the Examiner relies on
paragraph [0039] and Kneissl FIG. 3. Ans. 6, 7.
Relying on paragraph [0029] of Kneissl, the Appellant argues
“Kneissl explicitly states that the In mole fraction of FIG. 3 is merely with
regard to a ‘InGaN’ film (and not a film that includes Al).” App. Br. 16, 17.

3 The Appellant does not present separate arguments in support of the
patentability of dependent claims 3-5. Therefore, claims 3-5 stand or fall
with the patentability of claim 1. 37 C.F.R. § 41.37(c)(1)(vii).
Appeal 2011-009218
Application 12/073,215

8

Kneissl discloses that “FIG. 3 is a graph of the strength of the
piezoelectric field versus the indium content in InGaN layers in the nitride
semiconductor laser structure with a p-n tunnel junction of FIG. 2.”
Kneissl, para. [0029]. The Examiner recognizes as much. However, the
Examiner finds Kneissl discloses that InGaAlN layers are an alternative to
the InGaN layers referred to by the Appellant and would have also been
expected to have a ratio within the range recited in claims 2 and 6. Ans. 10,
11. The Appellant does not offer a response.
The Appellant has failed to establish reversible error in the
Examiner’s conclusion of obviousness. Therefore, the § 103(a) rejection of
claims 2 and 6 is sustained.
C. DECISION
The decision of the Examiner is affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1).

AFFIRMED

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