Ex Parte Ramdani et al

Patent Trial and Appeal Board

Dec 18, 2018

13617584 (P.T.A.B. Dec. 18, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/617,584 09/14/2012
27660 7590 12/20/2018
The Law Offices of Bradley J. Bereznak
465 S. Murphy A venue
Sunnyvale, CA 94086
FIRST NAMED INVENTOR
Jamal Ramdani
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www .uspto.gov
ATTORNEY DOCKET NO. CONFIRMATION NO.
03692.Bl56 4001
EXAMINER
HARGROVE, FREDERICK B
ART UNIT PAPER NUMBER
2819
NOTIFICATION DATE DELIVERY MODE
12/20/2018 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
bbereznak@bbpatent.com
jbereznak@bbpatent.com
BJBPATENT@YAHOO.COM
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte JAMAL RAMDANI, MICHAEL MURPHY, and LINLIN LIU
Appeal 2018-003112
Application 13/617,584
Technology Center 2800
Before LINDA M. GAUDETTE, CHRISTOPHER C. KENNEDY, and
LILAN REN, Administrative Patent Judges.
GAUDETTE, Administrative Patent Judge.
DECISION ON APPEAL 1
STATEMENT OF THE CASE
Appellants2 appeal under 35 U.S.C. § 134(a) from the Examiner's decision
finally rejecting claims 1, 12-24, 27, 28, 30, and 33-35. We have jurisdiction
under 35 U.S.C. § 6(b ).
We AFFIRM.
1 This Decision includes citations to the following documents: Specification filed
Sept. 14, 2012 ("Spec."); Final Office Action dated Jan. 27, 2017 ("Final"); Appeal
Brief filed Feb. 21, 2017 ("Appeal Br."); Examiner's Answer dated June 5, 2017
("Ans."); and Reply Brief filed July 24, 2017 ("Reply Br.").
2 Appellants identify Power Integrations, Inc. as the real party in interest. Appeal
Br. 1.
Appeal 2018-003112
Application 13/617,584
The "invention relates generally to high-voltage field effect transistors
(FE Ts); more specifically, to high-electron-mobility transistors (HEMTs)
and heterostructure field-effect transistors (HFETs ), and to methods of fabricating
such power transistor devices." Spec. ,r 1. Of the appealed claims, claims 1 and 20
are independent. Appeal Br. A-1-A-3. Claim 20 recites "[a] method of fabricating
a heterostructure semiconductor device" and includes limitations similar to those
recited in claim 1, reproduced below. Compare id. at A-2-A-3, with id. at A-1.
1. A heterostructure semiconductor device comprising:
a first active layer;
a second active layer disposed on the first active layer, a two-
dimensional electron gas layer forming between the first and second
active layers;
a first gate dielectric layer comprising a nitride-based compound
selected from the group consisting of silicon nitride (SiN), carbon
nitride (CN), and boron nitride (BN), the first gate dielectric layer being
disposed on the second active layer;
a second gate dielectric layer comprising aluminum oxide
(Ab03) disposed on the first gate dielectric layer, the first gate dielectric
layer having a first thickness and the second gate dielectric having a
second thickness, the second thickness being more than twice as large
as the first thickness, the first thickness being in a first range of
approximately 1-5 nanometers thick, and the second thickness being in
a second range of approximately 10-20 nanometers thick;
a passivation layer disposed over the second gate dielectric layer;
a gate that extends through the passivation layer to the second
gate dielectric layer, a bottom of the gate being vertically separated
from the second active layer by the first and second gate dielectric
layers; and
first and second ohmic contacts that electrically connect to the
second active layer, the first and second ohmic contacts being laterally
spaced-apart, the gate being disposed between the first and second
ohmic contacts.
Id. at A-1.
2
Appeal 2018-003112
Application 13/617,584
The Examiner relies on the following references as evidence of
unpatentability:
Kanamura et al. ("Kanamura") US 2006/0197107 Al
Iwakami et al. ("Iwakami") US 2006/0261356 Al
Wu et al. ("Wu") US 2007/0114569 Al
Derluyn et al. ("Derluyn") US 2010/0012977 Al
Herbert US 2010/0330754 Al
Tanaka et al. ("Tanaka") US 2012/0112263 Al
Van Hove ("Van Hove Pub") US 2012/0319169 Al
Sept. 7, 2006
Nov. 23, 2006
May 24, 2007
Jan. 21, 2010
Dec. 30, 2010
May 10, 2012
Dec. 20, 2012
Van Hove "CMOS Process-Compatible High-Power Low-Leakage AIGaN/Gan
MISHEMT on Silicon," May 2012. IEEE Electron Device Letters, Vol., 33. ("Van
Hove NPL").
The Examiner maintains the following grounds of rejection on appeal:
1. Claims 1, 12-24, 27, 28, 30, and 33-35 under 35 U.S.C. § 112(a) or
35 U.S.C. § 112 (pre-AIA), first paragraph, as failing to comply with the written
description requirement;
2. Claims 1, 12, 13, 15, 17, 18, 20, 22, 27, and 28 3 under 35 U.S.C.
§ I02(b) as anticipated by or, in the alternative, under 35 U.S.C. § I03(a) as
obvious over by Van Hove NPL;
3. Claims 21, 24, 30, and 34 under 35 U.S.C. § I03(a) as obvious over
Van Hove NPL in view of Van Hove Pub;
4. Claim 14 under 35 U.S.C. § I03(a) as obvious over Van Hove NPL in
view of Wu;
5. Claim 16 under 35 U.S.C. § I03(a) as obvious over Van Hove NPL in
view of Kanamura;
3 We view the Examiner's inclusion of claims 21, 24, 30-32, and 34 in the list of
claims subject to this ground of rejection as harmless error. Claims 31 and 32 are
no longer pending in the Application. The Examiner does not discuss claims 21,
24, 30, and 34 in the body of the rejection.
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Application 13/617,584
6. Claim 19 under 35 U.S.C. § 103(a) as obvious over Van Hove NPL in
view of Iwakami;
7. Claim 23 under 35 U.S.C. § 103(a) as obvious over Van Hove NPL in
view of Hebert;
8. Claim 33 under 35 U.S.C. § 103(a) as obvious over Van Hove NPL in
view of Tanaka; and
9. Claim 35 under 35 U.S.C. § 103(a) as obvious over Van Hove NPL in
view of Derluyn.
Rejection under 35 USC§ 112, written description requirement
Independent claims 1 and 20 recite "the first dielectric layer having a first
thickness and the second dielectric layer having a second thickness, the second
thickness being more than twice as large as the first thickness." Appeal Br. A-1, A-
3. Dependent claim 24 requires that "the second thickness is approximately 4 times
as thick as the first thickness." Id. at A-4. The Examiner finds there is no written
descriptive support for the recited range of thickness ratios in claims 1 and 20, and
for the recited thickness ratio in claim 24. Final 5---6.
Appellants argue the Examiner has not met the initial "burden of presenting
a prima facie case of unpatentability with respect to the written description
requirement." Appeal Br. 8. Appellants argue that even if we determine the
Examiner's findings are sufficient to support a prima facie case of unpatentability,
the Examiner reversibly erred in rejecting the claims under 35 U.S.C. § 112,
because the ordinary artisan would recognize from Figure 4 and Specification
paragraphs 23, 24, 33, 34, 43, and 50 that the inventor was in possession of the
claimed subject matter. Appeal Br. 11-13.
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Appeal 2018-003112
Application 13/617,584
The disclosure of a broad range of values does not by itself provide
written description support for a particular value within that range.
Instead, where a specification discloses a broad range of values and a
value within that range is claimed, the disclosure must allow one
skilled in the art to "immediately discern the limitation at issue in the
claims."
General Hospital Corp. v. Sienna Biopharmaceuticals, Inc., 888 F.3d 1368, 1372
(Fed. Cir. 2018) (quoting Purdue Pharma L.P. v. Paulding Inc., 230 F.3d 1320,
1323 (Fed. Cir. 2000)). In Purdue Pharma, the Federal Circuit affirmed a district
court finding that a claim requiring a pharmacokinetic concentration ratio above 2
was not supported by sufficient written description where the specification (1) did
not emphasize the concentration ratio as an aspect of the invention; (2) included
examples of ratios above and below 2; and (3) "disclose[d] a multitude of
pharmacokinetic parameters, with no blaze marks directing the skilled artisan to
the [concentration] ratio or what that ratio should exceed." 230 F.3d at 1326.
Similar to the facts in Purdue Pharma, the present Application's written
description does not discuss thickness ratio as an aspect of the invention. As found
by the Examiner, the Specification uses the terms "about" and "approximately" to
describe the thickness ranges for the first and second gate dielectric layers,
respectively, 1-5 nm and 10-20 nm. Ans. 2-3; see, e.g., Spec. ,r,r 24, 33, 34, 45.
These terms suggest that the invention, as described in the written description,
encompasses thickness ratios of 2 or less (e.g., where the first layer thickness is 5
nm or slightly greater than 5 nm and/or the second layer thickness is 10 nm or
slightly less than 10 nm). See Central Admixture Pharmacy Servs., Inc. v.
Advanced Cardiac Solutions, P.C., 482 F.3d 1347, 1355-56 (Fed. Cir. 2007)
( explaining that use of the term "about" avoids a strict numerical boundary to the
specified parameter). Unlike the specification in Purdue Pharma, however, the
present Specification includes only examples of first and second layer thicknesses
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Appeal 2018-003112
Application 13/617,584
that would result in a thickness ratio above 2 and, as discussed below, includes
some blaze marks directing the ordinary artisan to the claimed range of thickness
ratios.
The Specification describes two examples wherein the thickness of the first
gate dielectric layer is "substantially between 1-5 nanometers (nm) thick"-
suggesting that the first layer thickness is less than 5 nm-and the second gate
dielectric layer is "approximately 10-20 nm thick." Spec. ,r,r 23, 24; see id. ,r,r 43,
45. As noted above, a thickness ratio of 2 or less would exist only where the first
layer thickness is 5 nm or slightly greater than 5 nm and/or the second layer
thickness is 10 nm or slightly less than 10 nm). In other words, the ordinary
artisan would recognize that only a very small percentage of the first and second
layer thicknesses that fall within the disclosed ranges would result in a ratio of 2 or
less. The Specification discloses more specific examples wherein the thickness of
the first gate dielectric layer is "about 4 nm" and the thickness of the second gate
dielectric layer is "about 15 nm" (Spec. ,r,r 33, 34), resulting in a thickness ratio of
3.75 (Appeal Br. 12; Ans. 2). Appellants also point out that Figure 4 discloses test
results for a plurality of devices wherein thickness of the first gate dielectric layer
is about 4 nm and thickness of the second gate dielectric layer varies between
about 10 and 20 nm thick, which Appellants contend is a description of a thickness
ratio range of about 2.5 to 5.0. Appeal Br. 13. The Examiner does not address this
latter argument. See Ans. 2-3.
In sum, given that the only examples in the Specification are ones in which
the thickness ratio exceeds 2 and that there are a comparatively small number of
possible combinations of first and second thicknesses that would result in a
thickness ratio of 2, we are persuaded that the Examiner's rejection of claims 1 and
20 as failing to comply with the written description requirement of 35 U.S.C. § 112
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Application 13/617,584
is not supported by a preponderance of the evidence. See In re Wertheim, 541 F .2d
257,265 (CCPA 1976) ([I]n light of the description of the invention as employing
solids contents within the range of 25---60% along with specific embodiments of
36% and 50%, we are of the opinion that, as a factual matter, persons skilled in the
art would consider processes employing a 3 5---60% solids content range to be part
of appellants' invention .... The PTO has done nothing more than to argue lack of
literal support, which is not enough.").
Accordingly, we do not sustain the rejection of claims 1, 12-23, 27, 28, 30,
and 33-35. We do, however, sustain the rejection of claim 24 as Appellant does
not identify error in the facts and reasons relied on by the Examiner in rejecting
this claim. See Final 6; see generally Appeal Br. 9-13.
Rejection of claims 1, 12, 13, 15, 17, 18, 20, 22, 27, and 28
under 35 USC§ 102(b) as anticipated by or, in the alternative,
under 35 USC§ 103(a) as obvious over by Van Hove NPL
The Examiner's rejection under 35 U.S.C. § 102(b) is based on a finding that
that Figure 2 of Van Hove NPL, a transmission electron microscopy (TEM) cross-
section of a substrate with bilayer gate dielectric (see Van Hove NPL 668),
illustrates a thickness ratio between second and first dielectric layers of greater
than 2.0. Final 7-8. The Examiner acknowledges that Van Hove NPL describes the
layers of the Figure 2 device as a 5 nm ShN4 layer and a 10 nm Ah03 layer, but
contends "the authors provide[ d] round number labels in an attempt to describe the
picture of the device." Id. at 7.
We agree with Appellants that the Examiner's position lacks evidentiary
support and is based on conjecture. Appeal Br. 17. Accordingly, we do not sustain
the rejection of claims 1, 12, 13, 15, 17, 18, 20, 22, 27, and 28 under 35 U.S.C.
§ 102(b) as anticipated by Van Hove NPL.
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Application 13/617,584
The Examiner also rejects claims 1, 12, 13, 15, 17, 18, 20, 22, 27, and 28
under 35 U.S.C. § 103(a) as obvious over Van Hove NPL. As conceded by
Appellants, Van Hove NPL discloses a device comprising a 10 nm thick ShN4
layer and a 5 nm thick Ah03 layer (thickness ratio of 0.5) and a device comprising
a 5 nm thick ShN4 layer and a 10 nm thick Ab03 layer (thickness ratio of 2.0). See
Appeal Br. 15; Van Hove NPL 668.
Appellants argue the Examiner has not established a prima facie case of
obviousness because the "claimed thickness ratio and ranges do not overlap or lie
inside ranges disclosed in the prior art," and, therefore, the burden has not been
shifted to Appellants to show criticality in the claimed ranges. Appeal Br. 21.
Appellants' argument is not persuasive because "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." In re Peterson, 315 F.3d 1325, 1329 (Fed. Cir. 2003).
Appellants contend Van Hove NPL teaches away from a thickness ratio of
more than 2. Appeal Br. 19. Appellants argue that Van Hove NPL "Fig. 3(b) shows
that a device having a 10/5 nm ShN4/Ab03 first/second gate dielectric thickness
(ratio of 0.5) performs better, i.e., lower leakage current, than a ShNi Ab03 bilayer
gate dielectric having a ratio of 2.0." Id. As explained by the Examiner,
Appellants' argument is not persuasive because Van Hove NPL discloses that both
devices provide improved performance when compared to conventional devices.
See Ans. 5; Van Hove NPL 668 ("The forward bias gate leakage curves for wafers
with 10/5 nm and 5/10 nm ShN4/Ab03 gate dielectric are compared in Fig. 3(b) to
a reference wafer with 15-nm Ab03 only. By adding in situ ShN4 below Ab03, the
leakage current is reduced by several orders of magnitude."); In re Fulton, 391
F.3d 1195, 1201 (Fed. Cir. 2004) ("The prior art's mere disclosure of more than
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Application 13/617,584
one alternative does not constitute a teaching away from any of these alternatives
because such disclosure does not criticize, discredit, or otherwise discourage the
solution claimed in the ... application.").
Appellants argue the Specification includes evidence that the claimed
thickness ratio achieves unexpected results. Appeal Br. 22-24. We agree with the
Examiner that Appellants have not shown criticality in the claimed thickness ratio.
See Ans. 4---6. As noted above, the original Specification does not mention
thickness ratio. See supra p. 5. The thickness ranges for the first and second gate
dielectric layers encompass thickness ratios of 2 or less, see id., and there is no
explicit disclosure of unexpected results in, or even a preference for, "the second
thickness being more than twice as large as the first thickness" ( claims 1, 20). We
disagree with Appellants' assertion that Specification Figure 4 represents a
comparison with the closest prior art. See Appeal Br. 23-24. As acknowledged by
Appellants, Specification Figure 4 compares testing of devices wherein thickness
ratio ranges from about 2.5 to 5.0. Appeal Br. 13. There is no comparison to Van
Hove NPL's device wherein thickness ratio is 2.0. Moreover, the testing is not
persuasive of unexpected results because it is not commensurate in scope with the
claims. Although thickness of the second gate dielectric layer was varied in the
tested devices, thickness of the first gate dielectric layer was not varied. Spec. ,r 50;
see Appeal Br. 13 ("FIG. 4 shows results for a plurality of devices, each having a
first gate dielectric layer of about 4 nm thick .... "). There is no evidence
demonstrating that the same results would have been expected over the claimed
range of thicknesses for the first gate dielectric layer. See In re Kao, 639 F.3d
1057, 1068 (Fed. Cir. 2011).
In sum, we are not convinced of reversible error in the Examiner's
conclusion that claims 1, 12, 13, 15, 17, 18, 20, 22, 27, and 28 are unpatentable
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Appeal 2018-003112
Application 13/617,584
under 35 U.S.C. § 103(a) as obvious over Van Hove NPL. The rejection is
sustained.
Rejection of claims 21, 24, 30, and 34 under 35 USC§ 103(a)
as obvious over by Van Hove NPL in view of Van Hove Pub
Appellants argue the claims as a group. See generally Appeal Br. 24--29.
Accordingly, we decide patentability of the rejected claims based on claim 21. See
37 C.F.R. § 4I.37(c)(iv)(2016).
Claim 21 depends from method claim 20, and recites "depositing, prior to
the forming of the first and second ohmic contacts, a passivation layer over the
second gate dielectric layer." Appeal Br. A-3. The Examiner finds one of ordinary
skill in the art would have modified Van Hove NPL's method to include this step
based on Van Hove Pub's teaching that adding a passivation layer provides a
suitable HEMT arrangement. Final 13.
Appellants argue both Van Hove NPL and Van Hove Pub teach away from a
thickness ratio of more than 2. Appeal Br. 25-29. We are not persuaded that Van
Hove NPL teaches away from the claimed thickness ratio for the reasons discussed
above. Nor are we persuaded that Van Hove Pub teaches away from the claimed
thickness ratio, but agree with the Examiner that Van Hove Pub clearly teaches
that devices having thickness ratios of both 0.5 and 2.0 provide improved
performance when compared to conventional devices. See Ans. 7-8; Van Hove
Pub ,r,r 153, 154, 175, 176.
Accordingly, we sustain the rejection of claims 21, 24, 30, and 34.
Rejections of claims 14, 16, 19, 23, 33, and 35 under 35 USC§ 103(a)
As to the rejections of claims 14, 16, 19, 23, 33, and 35, Appellants argue
the Examiner reversibly erred in finding one of ordinary skill in the art would have
been motivated to modify Van Hove NPL in view of the secondary references.
Appeal Br. 29-32. Appellants' arguments are not persuasive because they fail to
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Application 13/617,584
identify error in the Examiner's fact finding and reasoning. Compare Final 15-18
and Ans. 8-12, with Appeal Br. 29-32.
As to claim 33, Appellants also argue Tanaka is non-analogous art. Appeal
Br. 31-32. This argument is unpersuasive for the reasons explained by the
Examiner in the Answer. See Ans. 11.
Because Appellants have not identified reversible error in the Examiner's
conclusion of obviousness as to claims 14, 16, 19, 23, 33, and 35, we sustain these
grounds of rejection.
Any additional arguments made by Appellants but not discussed in this
Decision have been considered, but were not found persuasive for the reasons
explained in the Answer.
Order
1, 12-24, § 112(a), 24 1, 12-23,
27, 28, 30, or§ 112, 27, 28, 30,
and 33-35 ,r 1, and 33-35
written
description
1, 12, 13, § 102(b) VanHoveNPL 1, 12, 13,
15, 17,18, 15, 17, 18,
20, 22, 27, 20, 22, 27,
and28 and28
1, 12, 13, § 103(a) VanHoveNPL 1, 12, 13, 15,
15, 17,18, 17, 18,20,
20, 22, 27, 22, 27, and
and28 28
21, 24, 30, § 103(a) VanHoveNPL 21, 24, 30,
and 34 and Van Hove and 34
Pub
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Application 13/617,584
14 § 103(a)
16 § 103(a)
19 § 103(a)
23 § 103(a)
33 § 103(a)
35 § 103(a)
Summary
VanHoveNPL 14
and Wu
VanHoveNPL 16
and Kanamura
VanHoveNPL 19
and I wakami
VanHoveNPL 23
and Hebert
VanHoveNPL 33
and Tanaka
VanHoveNPL 35
and Derlu n
1, 12-24, 27,
28,30,and
33-35
No time period for taking any subsequent action in connection with this
appeal may be extended under 37 C.F.R. § 1.136(a)(l )(iv).
AFFIRMED
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