Ex Parte Matocha

Patent Trial and Appeal Board

Oct 12, 2012

11295915 (P.T.A.B. Oct. 12, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte KEVIN SEAN MATOCHA
____________

Appeal 2010-004971
Application 11/295,915
Technology Center 2800
____________

Before JOSEPH F. RUGGIERO, DENISE M. POTHIER, and
JENNIFER L. McKEOWN, Administrative Patent Judges.

McKEOWN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the Examiner’s rejection
of claims 1-23 as obvious. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

STATEMENT OF THE CASE
Appellant’s invention is a method of fabricating a silicon carbide
(SiC) semiconductor device including a gate oxide layer that is ion-
implanted to decrease the interface state density at the interface between the
Appeal 2010-004971
Application 11/295,915

2
SiC and gate oxide layer while improving the channel mobility. (See
generally Abstract; Spec. ¶ [0012].) Claim 1 is illustrative and is reproduced
below, with the key disputed limitation emphasized:
1. A method comprising:
forming a source region and a drain region over a silicon
carbide layer;
subjecting the source region and the drain region to a
temperature greater than about 1400°C;
subsequently, forming a gate oxide layer over the silicon
carbide layer; and
ion-implanting an atomic species into the gate oxide
layer.
Claim 13 also recites the same ion-implanting limitation.

THE REJECTION1
The Examiner rejected claims 1-23 under 35 U.S.C. § 103(a) as
unpatentable over Ryu (US 2004/0119076 A1; published June 24, 2004) and
Yuusuke Maeyama et al., Improvement of SiO2/SiC Interface Properties by
Nitrogen Radical Irradiation, 42 JAPAN J. APPLIED PHYSICS L575-77 (2003).
(Ans. 4-6.)

1 The Examiner objected to the Specification for failing to provide proper
antecedent basis for the claimed subject matter recited in claims 2 and 14.
Office Action 2 (Feb. 6, 2009). Since this is a petitionable, not appealable,
matter under 37 C.F.R. § 1.181, we will not address this objection. See
MPEP § 706.01 (“[T]he Board will not hear or decide issues pertaining to
objections and formal matters which are not properly before the Board.”);
see also MPEP § 1201 (“The Board will not ordinarily hear a question that
should be decided by the Director on petition . . . .”).
Appeal 2010-004971
Application 11/295,915

3
CONTENTIONS
The Examiner finds that Ryu discloses every recited feature of
representative claim 1 except for ion-implanting an atomic species into the
gate oxide layer, but cites Maeyama as teaching this feature in concluding
that the claim would have been obvious. (Ans. 4-6.)
Appellant argues that Ryu and Maeyama collectively do not teach or
suggest the ion-implanting limitation of claim 1. (App. Br. 12-15.) In
particular, Appellant asserts that the Examiner incorrectly equates
Maeyama’s ion-irradiation technique with the claimed ion-implantation
limitation. (App. Br. 12.) Further, Appellant contends that the Examiner
“has not shown the requisite motivation or suggestion to combine the cited
references . . . .” (App. Br. 14.)

ISSUES
(1) Under § 103, has the Examiner erred by finding that Ryu and
Maeyama, collectively, would have taught or suggested ion-implanting an
atomic species into the gate oxide layer as recited in claim 1?
(2) Is the Examiner’s reason to combine the teachings of these
references supported by articulated reasoning with some rational
underpinning to justify the Examiner’s obviousness conclusion?

ANALYSIS
Claims 1 and 13
On this record, we find no error in the Examiner’s obviousness
rejection of exemplary claim 1. Appellant contends that Maeyama does not
teach or suggest the claimed ion implanting step because Maeyama discloses
Appeal 2010-004971
Application 11/295,915

4
an ion irradiation technique, not ion implantation. (App. Br. 12-14.) Based
upon the record before us, we disagree.
Appellant primarily relies on conclusory statements without providing
persuasive evidence or reasoning to support the contention that ion
irradiation and ion implantation are different. For example, Appellant
maintains that one of skill in the art knows “that ion implantation and ion
irradiation are two completely different techniques of burying nanostructures
in fabrication of various articles.” (App. Br. 12-13; Reply Br. 3.) Notably
absent though is supporting evidence or a description of how these processes
are “completely different.” Instead, Appellant merely states that ion
irradiation is “employed for taming nanostructures” while ion implantation
is “primarily employed for growth of nanostructures.” (App. Br. 13
(emphases omitted).) Identifying potential different uses of these
techniques, without more, fails to persuasively distinguish between them as
claimed.
Then, for the first time in the Reply Brief, Appellant provides a single
figure to support the distinction between ion irradiation and ion
implantation. Submitting new evidence in the reply brief is untimely, and
the new evidence will not be admitted. See 37 C.F.R. § 41.33(d)(2) (stating
that other evidence filed after the date of filing an appeal will not be
admitted); 37 C.F.R. § 41.41(a)(2) (“A reply brief shall not include . . . any
new or non-admitted affidavit or other evidence.”).
Nonetheless, the cited website does not support Appellant’s argument.
(See Ion Implantation und Ion Irradiation,
http://www.fzd.de/db/Cms?pNid=61 &pOid=24324 (last visited
Oct. 3, 2012).) For example, the website introduces the cited figure by
Appeal 2010-004971
Application 11/295,915

5
stating that “[i]n general, for the application of ion implantation to the
fabrication of (buried) nanostructures two physical principles [i.e. the
depicted ion implantation and ion irradiation processes] can be used.” (Id.
(emphasis added).) In other words, the website at least identifies ion
irradiation as a form of ion implantation. Therefore, Appellant fails to
provide persuasive evidence to support that one of skill in the art would
understand ion irradiation and ion implantation to be different processes.
The Examiner, on the other hand, persuasively explains that
Maeyama’s ion irradiation meets the claimed ion implantation limitation.
(Ans. 5, 8.) For example, the Examiner states that Maeyama’s ion
irradiation process exposes the gate oxide to nitrogen ions and the nitrogen
ions are introduced (e.g., implanted) into the gate oxide layer. (Ans. 5
(citing Maeyama L575, ll. 29-38, L576, ll. 3-5).) And because “the
irradiation step of Maeyama implants ions into the gate oxide, it can
reasonably be considered an ion implantation step.” (Ans. 9.)
Appellant rebuts the Examiner’s finding by highlighting that the
broadest reasonable interpretation of a claim term must be consistent with
the Specification. (Reply Br. 4-5.) Appellant, however, then fails to explain
how the Examiner’s interpretation of ion-implantation is inconsistent with
the disclosure. Here, the Specification generally describes that “the gate
oxide layer is ion-implanted with an atomic species.” (Spec. ¶ [0018].)
Additionally, Appellant admits that ion irradiation is at least one way to bury
or implant ions into an article. (See App. Br. 12-13; Reply Br. 3 (stating that
ion irradiation does “bury[] nanostructures in fabrication of various
articles.”) We see no basis, nor has Appellant provided any, to find that the
Appeal 2010-004971
Application 11/295,915

6
Examiner’s interpretation of the claimed ion-implantation limitation is
inconsistent with the Specification and therefore improper.
To further support the finding that ion irradiation is an ion
implantation method, the Examiner also discusses Murakoshi (US 6,646,268
B2; Nov. 11, 2003). (Ans. 7, 9 (citing Murakoshi, col. 1, ll. 21-22).)
Appellant argues that the Examiner incorrectly takes “two distinct concepts
of ion implantation and ion irradiation out of the broader context of ion
generation and mistakeningly equating them.” (Reply Br. 3-4 (emphasis
omitted).) We disagree. As identified by the Examiner, Murakoshi states
“[t]he ion implantation method (ion irradiation method) is widely employed
as a method of forming pn junction by introducing with an impurity . . . into
a semiconductor substrate.” (Ans. 7 (citing Murakoshi col. 1, ll. 24-28); see
also Murakoshi claim 5 (reciting an ion irradiation apparatus for ion
implantation).) Murakoshi’s reference to ion generation separately does not
negate Murakoshi’s support for the Examiner’s finding that one of skill in
the art would consider ion irradiation a method of ion implantation.
Appellant further contends that “it is not clear on what technical basis
Murakoshi may be cited as an objective [sic] evidence to support that
Maeyama discloses ion implantation.”2 (Reply Br. 4.) As noted above, the
Examiner’s reliance on Maeyama to teach ion implantation has not been
sufficiently rebutted. Nonetheless, “extrinsic evidence may be considered

2 Appellant also requests that if the Examiner is relying on Murakoshi as
disclosing any of the claimed features that Murakoshi be cited as a reference
either alone or in combination with Ryu and Maeyama. (Reply Br. 4.) To
the extent Appellant is arguing that the Examiner should have identified a
new ground of rejection, we note that this is a petitionable matter, not before
us on appeal. See 37 C.F.R. § 1.181(a).
Appeal 2010-004971
Application 11/295,915

7
when it is used to explain, but not expand, the meaning of a reference.” In
re Baxter Travenol Labs., 952 F.2d 388, 390 (Fed. Cir. 1991) (internal
citation omitted); see also In re Grasselli, 713 F.2d 731, 739 (Fed. Cir.
1983). Here, the Examiner merely relies on Murakoshi to further support
how one of ordinary skill in the art would understand the term ion
irradiation.
Accordingly, based upon the record before us, we agree with the
Examiner that Maeyama teaches or suggests ion-implanting.
Next, Appellant argues that “Maeyama is not related to
ion-implantation technique as a part of a method of fabricating a silicon
carbide device.” (App. Br. 13 (emphasis omitted).) This argument is also
unavailing because being part of a method of fabricating a silicon device is
not a claimed limitation. (See App. Br. 18-20 (Claims 1 and 13 reciting “a
method” including the step of “ion-implanting an atomic species into the
gate oxide layer.”).) Even so, Maeyama does discuss techniques used in
making semiconductor structures made from silicon. (See Abstract; see also
Ans. 8).
Finally, Appellant argues that “the Examiner has not shown the
requisite motivation or suggestion to combine the cited references to reach
the present claims.” (App. Br. 14.) In particular, Appellant contends that
the Examiner relied on a conclusory and subjective statement. To the
contrary, the Examiner properly identifies that Ryu disclose a silicon dioxide
(SiO2)/SiC interface and that it would be obvious to expose the gate oxide
(SiO2) of Ryu to nitrogen radicals, as taught by Maeyama, with the
motivation to improve the electric properties at the SiO2/SiC interface.
(Ans. 5 (citing Maeyama L576, ll. 14-16).)
Appeal 2010-004971
Application 11/295,915

8
Appellant also states that “[t]here is no objective evidence on how an
invention on fabricating a silicon carbide metal-oxide semiconductor field
effect transistor unit cell can be combined with an invention on a technique
of improvement of SiO2/SiC Interface [sic] properties by nitrogen radical
irradiation to arrive at the present application.” (App. Br. 15.) However,
“[t]he test for obviousness is not whether the features of a secondary
reference may be bodily incorporated into the structure of the primary
reference . . . . Rather, the test is what the combined teachings of the
references would have suggested to those of ordinary skill in the art.” In re
Keller, 642 F.2d 413, 425 (CCPA 1981). “[I]f a technique has been used to
improve one device, and a person of ordinary skill in the art would recognize
that it would improve similar devices in the same way, using the technique is
obvious unless its actual application is beyond his or her skill.” KSR Int’l
Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007). Here, one of ordinary skill
would recognize the advantages of exposing the gate oxide (SiO2) of Ryu to
nitrogen radicals, as taught by Maeyama, to improve interface properties.
Appellant’s argument is thus unavailing.
Accordingly, we are therefore not persuaded that the Examiner erred
in rejecting claim 1 and independent claim 13, which is not separately
argued and has a similar ion-implanting step disputed by Appellant.

Claims 2-12 and 14-23
Because Appellant relies on the same arguments with respect to the
remaining claims (App. Br. 16), we also sustain the Examiner’s obviousness
rejection of dependent claims 2-12 and 14-23 (Ans. 4-6) for the reasons
noted above.
Appeal 2010-004971
Application 11/295,915

9

CONCLUSION
The Examiner did not err in rejecting claims 1-23 under § 103.

ORDER
The Examiner’s decision rejecting claims 1-23 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)(iv).

AFFIRMED

babc