DETAILED ACTION
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1, 9 and 11-15 are rejected under 35 U.S.C. 102 (a)(1) as being anticipated by JIANGBIN WU et al., "High tunnelling electroresistance in a ferroelectric van der Waals heterojunction via giant barrier height modulation" Nature Electronics volume 3, pages 466-472 (hereinafter; “Wu”).
In regard to claim 1, Wu teaches a device (a ferroelectric tunnel junction (FTJ)) (Fig. 1a [pg. 1, col.1, ln. 1]), comprising:
a first contact made of a semi-metallic material (a graphene contact) (Fig. 1a and [pg. 1, col.2, ln. 14]);
a second contact made of a metal material (a chromium layer (CR)), the first contact and the second contact forming asymmetric electrodes (the two electrodes are asymmetrical as described in [pg. 1, col.2, ln. 14-15]) (Fig. 1a); and
a ferroelectric insulating layer (a CuInP2S6 (CIPS) layer) disposed between the first contact and the second contact and electrically connected to the first contact and the second contact ( the layered CIPS is used as the ferroelectric tunnelling barrier layer, and graphene and Cr are used as the asymmetric electrodes) (Fig. 1a and [pg. 1, col.2, ln. 14-15]).
In regard to claim 9, Wu teaches wherein the first ferroelectric insulating layer comprises CuInP2S6 (Wu teaches the use of two-dimensional (2D) van der Waals (vdW) materials such as CuInP2S6 (CIPS)).
In regard to claim 11, Wu teaches wherein the ferroelectric insulating layer is a two-dimensional van der Waals material (CuInP2S6 is a known two-dimensional (2D) van der Waals (vdW) material).
In regard to claim 12, Wu teaches wherein the first contact comprises graphene (the contact is a graphene contact) (Fig. 1a and [pg. 1, col.2, ln. 14]).
In regard to claim 13, Wu teaches wherein the first contact comprises monolayer graphene (monolayer graphene (1LG) is used as asymmetric electrodes) (Fig. 1a and [pg. 1, col.2, ln. 14]).
In regard to claim 14, Wu teaches wherein the second contact comprises chromium (a chromium layer (Cr) forms a second contact as described above).
In regard to claim 15, Wu teaches wherein the asymmetric electrodes cause a large modulation of average barrier height (ABH) when ferroelectric polarization changes direction, exponentially influencing the tunneling current ([pg. 1, col.2, ln. 1-6]).
Claims 1-2, 16 and 18-20 are rejected under 35 U.S.C. 102 (a)(1) as being anticipated by Wu. This rejection of claim 1 relies on different elements mapped as the first contact from the claim 1 rejection above. This rejection of claim 1 will be referred to as claim 1A in dependent claim 35 U.S.C 103 rejections shown below.
In regard to claim 1, Wu teaches a device (a ferroelectric tunnel junction (FTJ)) (Fig. 1a [pg. 1, col.1, ln. 1]), comprising:
a first contact made of a semi-metallic material (a graphene contact formed from a graphene bilayer) (Fig. 1a, Fig. 4a, [pg. 1, col.2, ln. 14] and [pg. 5, col.2, ln. 14-15]);
a second contact made of a metal material (a chromium layer (CR)), the first contact and the second contact forming asymmetric electrodes (the two electrodes are asymmetrical as described in [pg. 1, col.2, ln. 14-15]) (Fig. 1a); and
a ferroelectric insulating layer (a CuInP2S6 (CIPS) layer and a top layer of a graphene bilayer) disposed between the first contact and the second contact and electrically connected to the first contact and the second contact (the layered CIPS is used as the ferroelectric tunnelling barrier layer, and graphene and Cr are used as the asymmetric electrodes) (Fig. 1a, Fig. 4a, [pg. 1, col.2, ln. 14] and [pg. 5, col.2, ln. 14-15]).
In regard to claim 2, Wu teaches wherein the ferroelectric insulating layer comprises a first ferroelectric layer and a graphene layer sandwiched together (the top layer of the graphene bilayer layer and the CIPS layer would be sandwiched between the top chromium layer and the bottom graphene layer of the graphene bilayer) ([pg. 5, col.2, ln. 14-18]).
In regard to claim 16, Wu teaches a device comprising:
a first contact made of graphene material (a graphene contact formed from the graphene bilayer) (Fig. 1a, Fig. 4a, [pg. 1, col.2, ln. 14] and [pg. 5, col.2, ln. 14-15]);
a second contact made of chromium (a chromium layer (CR)), the first contact and the second contact forming asymmetric electrodes (the two electrodes are asymmetrical as described in [pg. 1, col.2, ln. 14-15]) (Fig. 1a);
a first ferroelectric layer comprising CuInP2S6 and a graphene layer comprising monolayer graphene disposed between the first contact and the second contact (the top layer of the graphene bilayer layer and the CIPS layer would be sandwiched between the top chromium layer and the bottom graphene layer of the graphene bilayer) ([pg. 5, col.2, ln. 14-18]).
In regard to claim 18, Wu teaches a device comprising:
a pair of asymmetric electrodes, each electrode of the pair of asymmetric electrodes being of a different material (a bottom layer of a graphene bilayer and chromium electrode are asymmetrical as described in [pg. 1, col.2, ln. 12-15]) (Fig. 1a, Fig. 4a, [pg. 1, col.2, ln. 14] and [pg. 5, col.2, ln. 14-15]); and
a ferroelectric insulating layer disposed between the pair of asymmetric electrodes and providing a ferroelectric tunnel junction (the layered CIPS used as the ferroelectric tunnelling barrier layer and the top layer of the graphene bilayer function as the ferroelectric tunnel junction) (Fig. 1a and [pg. 1, col.2, ln. 12-15]);
wherein a change of direction of ferroelectric polarization causes a large modulation of average barrier height of the ferroelectric insulating layer between the pair of asymmetric electrodes (an ultra-thin ferroelectric layer is used as the tunnelling barrier and its average barrier height (ABH) can be modified by switching the ferroelectric polarization as taught by Wu) ([pg. 1, col.2, ln. 4-6]).
In regard to claim 19, Wu teaches wherein the pair of asymmetric electrodes includes a first electrode made of a semi-metallic material and a second electrode made of a metallic material (the two electrodes are made of chromium and graphene) ([pg. 1, col.2, ln. 12-15]).
In regard to claim 20, Wu teaches wherein the ferroelectric insulating layer includes a first ferroelectric layer and a graphene layer (the layered CIPS used as the ferroelectric tunnelling barrier layer and the top layer of the graphene bilayer function as the ferroelectric tunnel junction).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Wu as applied to claim 1A above, and further in view of Ino et al. (US 2016/0365133 A1; hereinafter “Ino”)
In regard to claim 3, Wu doesn’t explicitly teach wherein the ferroelectric insulating layer further comprises a first insulating buffer layer disposed between the first ferroelectric layer and the graphene layer.
Ino teaches a device (memory cell 101 is a two-terminal FTJ) (Fig. 1 and paragraph 34), wherein a ferroelectric insulating layer (a first low oxygen concentration conductive layer 22, an insulating film 24, and a ferroelectric film 26 of hafnium oxide comprise the ferroelectric insulating layer) further comprises a first insulating buffer layer (an insulating film 24) disposed between a first ferroelectric layer and a graphene layer (the insulating film 24 is shown disposed between the first low oxygen concentration conductive layer formed of graphene and the ferroelectric film 26 of hafnium oxide in Fig. 1) (Fig. 1 and paragraphs 42 and 45).
It would have been obvious to one skilled in the art to combine the teachings of Wu with the teachings of Ino to have the ferroelectric insulating layer further comprises a first insulating buffer layer disposed between the first ferroelectric layer and the graphene layer since this layout reduces the polarization degradation at the ferroelectric layer, and therefore, the number of times data can be rewritten is increased as taught by Ino (paragraph 30).
Claims 4 -7 are rejected under 35 U.S.C. 103 as being unpatentable over Wu in view of Ino as applied to claim 3 above, and further in view of Geim, A. K. “Van Der Waals Heterostructures.” Nature. 499 (2013): 419–425. Web; hereinafter “Geim”.
In regard to claim 4, Wu in view of Ino doesn’t explicitly teach wherein the first ferroelectric layer comprises a bulk ferroelectric material and wherein the first ferroelectric insulating buffer layer comprises monolayer hexagonal boron nitride.
Geim teaches a device (‘vertical’ devices) ([pg. 421, col.2, ln.26]), wherein the first ferroelectric layer comprises a bulk ferroelectric material and wherein the first ferroelectric insulating buffer layer comprises monolayer hexagonal boron nitride (Geim teaches mono- layers of hBN were used as tunnel barriers with graphene layers as taught by Geim) ([pg. 421, col.2, ln.45-47]).
It would have been obvious to one skilled in the art to combine the teachings of Wu in view of Ino with the teachings of Geim to have the first ferroelectric layer comprises a bulk ferroelectric material and wherein the first ferroelectric insulating buffer layer comprises monolayer hexagonal boron nitride since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
In regard to claim 5, Wu in view of Ino doesn’t explicitly teach wherein the first ferroelectric layer comprises a bulk ferroelectric material and wherein the first ferroelectric insulating buffer layer comprises multilayer hexagonal boron nitride.
Geim teaches a device (vertical devices) ([pg. 421, col.2, ln. 26]), wherein the first ferroelectric layer comprises a bulk ferroelectric material and wherein the first ferroelectric insulating buffer layer comprises multilayer hexagonal boron nitride (Geim teaches a few layers of hBN were used as tunnel barriers with graphene layers as taught by Geim) ([pg. 420, col.2, ln. 53]).
It would have been obvious to one skilled in the art to combine the teachings of Wu in view of Ino with the teachings of Geim to have the first ferroelectric layer comprises a bulk ferroelectric material and wherein the first ferroelectric insulating buffer layer comprises multilayer hexagonal boron nitride since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
In regard to claim 6, Wu in view of Ino and Geim teach wherein the bulk ferroelectric material comprises at least one of HfO2 and Hf0.5Zr0.5O2 (Ino teaches the ferroelectric film 26 can be HfO2 and Hf0.5Zr0.5O2) (paragraph 53).
In regard to claim 7, Wu in view of Ino and Geim teach wherein the bulk ferroelectric material comprises at least one of HfO2 and Hf0.5Zr0.5O2 (Ino teaches the ferroelectric film 26 can be HfO2 and Hf0.5Zr0.5O2) (paragraph 53).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Wu in view of Ino as applied to claim 3 above, and further in view of Lee (US 2018/0269216 A1).
In regard to claim 8, Wu in view of Ino don’t explicitly teach wherein the first ferroelectric layer comprises a perovskite-based ferroelectric material.
Lee teaches a device (a ferroelectric memory device 10) (Fig. 1 and paragraph 22), wherein a first ferroelectric layer (a first tunnel barrier layer 120) comprises a perovskite-based ferroelectric material (the first tunnel barrier layer 120 may include a perovskite-based material).
It would have been obvious to one skilled in the art to combine the teachings of Wu in view of Ino with the teachings of Lee to have the first ferroelectric layer comprises a perovskite-based ferroelectric material since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
In regard to claim 10, Wu teaches the first ferroelectric insulating layer comprises α-In2Se3.
Wu teaches it is known that two-dimensional (2D) van der Waals (vdW) materials such as CuInP2S6 (CIPS) and α-In2Se3 are used in ferroelectric tunnel junction. Therefore, the examiner takes official notice that it would have been obvious to one skilled in the art to use α-In2Se3 as a first ferroelectric insulating layer.
Claim 17 is rejected under 35 U.S.C. 103 as being unpatentable over Wu as applied to claim 16 above, and further in view of Ino and Geim.
In regard to claim 17, Wu doesn’t explicitly teach a first insulating buffer layer disposed between the first ferroelectric layer and the graphene layer, wherein the first insulating buffer layer comprises hexagonal boron nitride.
Ino teaches a device (memory cell 101 is a two-terminal FTJ) (Fig. 1 and paragraph 34), further comprising a first insulating buffer layer (an insulating film 24) disposed between the first ferroelectric layer and the graphene layer (the insulating film 24 is shown disposed between the first low oxygen concentration conductive layer formed of graphene and the ferroelectric film 26 of hafnium oxide in Fig. 1) (Fig. 1 and paragraphs 42 and 45).
It would have been obvious to one skilled in the art to combine the teachings of Wu with the teachings of Ino to have a first insulating buffer layer disposed between the first ferroelectric layer and the graphene layer since this layout reduces the polarization degradation at the ferroelectric layer, and therefore, the number of times when data can be rewritten is increased as taught by Ino (paragraph 30).
Geim teaches a device (‘vertical’ devices) ([pg. 421, col.2, ln. 26]),wherein the first ferroelectric insulating buffer layer comprises hexagonal boron nitride (Geim teaches layers of hBN were used as tunnel barriers with graphene layers as taught by Geim).
It would have been obvious to one skilled in the art to combine the teachings of Wu in view of Ino with the teachings of Geim to have the first ferroelectric insulating buffer layer comprises monolayer hexagonal boron nitride since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEYON ALI-SIMAH PUNCHBEDDELL whose telephone number is (571)270-0078. The examiner can normally be reached Mon-Thur: 7:30AM-3:30 PM.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Sue Purvis can be reached at (571) 272-1236. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/SEYON ALI-SIMAH PUNCHBEDDELL/ Examiner, Art Unit 2893
/SUE A PURVIS/Supervisory Patent Examiner, Art Unit 2893