Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Allowable Subject Matter
Claims 5-7, 9-12, 18-20 objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 1, 13, 14, 16, 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over An et al. (US 20150243826 A1) hereafter referred to as An in view of Gruen et al. (US 20200381645 A1) hereafter referred to as Gruen
In regard to claim 1 An teaches an electromagnetic wave detector [see Fig. 1, Fig. 2(a) see paragraph 0011, 0030 “graphene/Si heterojunction photosensing devices, switched between a photodiode mode (Mode1)” “by using large-area CVD-grown graphene overlaid on Si, the architectures described herein may remain conformal to conventional semiconductor processing, and will be able to span over ten decades or more of incident power using the combination of Mode1 and Mode2, as shown in FIG. 1” ] comprising:
a semiconductor [see lightly n-doped Si] layer;
an insulating layer [see SiO2] disposed on the semiconductor layer and having [see in the middle] an opening;
a two-dimensional material layer [see Graphene] extending from on the opening to [see Fig. 1, Fig. 2(a)] on the insulating layer, including a connection part [see Graphene is on the SiO2] in contact with a peripheral part of the insulating layer facing the opening, and electrically connected [see “graphene/Si heterojunction”, see paragraph 0035, 0083 “With respect to Mode1 (Tunable Graphene/Si Photodiode), graphene/Si junctions have been reported to form a Schottky-type barrier at the interface, and when illuminated, the photoexcitation of carriers occur in Si, resulting in carrier injection into graphene” “The graphene/Si and TTG/Si heterojunction devices were fabricated on commercially purchased lightly n-doped (resistivity of 1-10 .OMEGA.-cm) Si wafers with 400 nm SiO.sub.2 layer. These wafers were diced into square pieces of 2 cm edges for device preparation. First, the front surface of SiO.sub.2/Si wafers were patterned by photolithography and wet-etching of the SiO.sub.2 layer (using a buffered oxide etchant) to prepare square windows (5 mm.times.5 mm) where the n-doped silicon was exposed. The back surface oxide was also etched out during this process. Next, an e-beam deposition technique was used to deposit rectangular Ti/Au (5 nm/100 nm) film contact pads along the periphery of the Si window on the front (FIG. 12), as well as on the back surface of Si squares, leaving the front windows exposed. To transfer graphene and TTG films onto this window or other substrates, the as-grown graphene and TTG films (on metal foils) were spin-coated with PMMA, and the metal foils were dissolved in a dilute FeCl.sub.3 solution. The PMMA-coated graphene and TTG films were then transferred onto the top of the exposed square window of Si, ensuring that they covered the window and extended onto the Au part of the top contact. After that, the devices were thoroughly rinsed with acetone and isopropanol to remove the PMMA, and dried”] to the semiconductor layer;
a first electrode part [see the top Au/Ti] disposed on the insulating layer and electrically connected [see voltage application in Mode 1] to the two-dimensional material layer;
a second electrode part [see the bottom Au/Ti] electrically connected [see voltage application in Mode 1] to the semiconductor layer; and
the two-dimensional material layer is in contact with a part of the semiconductor layer [see “graphene/Si heterojunction” in the middle] positioned inside of the opening in a planar view
but does not teach
a unipolar barrier layer disposed between the semiconductor layer and the connection part of the two-dimensional material layer and electrically connected to each of the semiconductor layer and the two-dimensional material layer,
wherein the unipolar barrier layer has an annular portion disposed annularly in interior of the opening in a planar view, and
and that the two-dimensional material layer is in contact with a part of the semiconductor layer positioned inside of the annular portion in a planar view.
The Examiner notes that a person of ordinary skill in the art is aware that graphene has a zero bandgap thus it is ambipolar.
See Gruen teaches contact doping of graphene, see paragraph 0038, 0048 “contact doping of graphene, lowering of cell series resistance, increasing work function differences and other matters pertaining to maximizing the performance parameters of the new generation of solar cells disclosed herein are detailed below. Further, while reference may be made to zinc oxide in many areas herein, it should be appreciated that other wide band-gap materials may be used in the alternative and/or in combination with zinc oxide in certain forms”, “nanowire cores may also include a variety of different materials. For example, a variety of wide bandgap materials may be used. Such wide bandgap materials may include, but are not limited to, zinc oxide, boron, titanium, silicon borides, carbides, nitrides, oxides, or sulfides, combinations thereof, and the like. Wide band-gap material will be understood to refer to a material having a valence band and a conduction band that differ by at least two volts. In one form, zinc oxide may be especially suitable for at least some of the techniques and combinations of materials discussed herein” “work function changes are due to a redistribution of charge that occurs when graphene comes into contact with ZnO, with the graphene interacting with ZnO in just the requisite manner, perhaps because its ambipolarity allows it to act as an electron acceptor” “the resulting large difference in work functions might make the graphene/ZnO junction favorable for charge separation” see paragraph 0074, 0085 “ZnO starts out as an n-type semiconductor, but when in contact with graphene material the ZnO transfers excess electrons to the graphene and the graphene becomes an n-type region that contains negatively charged electrons and ZnO becomes a p-type region that contains positive charge carriers. As is confirmed by experimental investigations presented in more detail below, the graphene coating absorbs photons of sunlight and a flow of electrons occurs from the graphene to the ZnO” “Charge separation occurs at the junction of graphene with ZnO yielding photocurrent at a cell voltage up to 2.4 V”.
The Examiner notes that the teaching of Gruen is essentially benefit of using a higher bandgap to interact with graphene.
See the portion of SiO2 in An Fig. 1 around the opening in SiO2 has graphene on it and that portion is wasted space and can be replaced by suitable high bandgap material, in order to emulate the teachings of Gruen.
Thus, it 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 to modify An to add a high bandgap material to interact with graphene to affect work function i.e. to modify An to include that a unipolar barrier layer disposed between the semiconductor layer and the connection part of the two-dimensional material layer and electrically connected to each of the semiconductor layer and the two-dimensional material layer, wherein the unipolar barrier layer has an annular portion disposed annularly in interior of the opening in a planar view, and and that the two-dimensional material layer is in contact with a part of the semiconductor layer positioned inside of the annular portion in a planar view.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is to replace a portion of SiO2 window around the opening with a high bandgap material to interact with graphene to affect doping and work function and generate higher photoresponse output.
In regard to claim 13 An and Gruen as combined teaches wherein a material forming the unipolar barrier layer [see Gruen teaches high bandgap oxide semiconductor] is oxide semiconductor.
In regard to claim 14 An and Gruen as combined teaches [see paragraph 0048 An teaches application of imaging, “the systems and devices described herein may be employed in infrared detectors and sensors, imaging devices”] wherein the electromagnetic wave detectors are disposed to be aligned along at least one of a first direction and a second direction intersecting the first direction.
In regard to claim 16 An and Gruen as combined teaches [see paragraph 0034 An teaches “carbon-based material may be doped, such as p-doped or n-doped”] wherein the conductivity type of the two-dimensional material layer is the same as the conductivity type of the semiconductor layer.
In regard to claim 17 An and Gruen as combined teaches [see paragraph 0034 An teaches “carbon-based material may be doped, such as p-doped or n-doped. In one embodiment, the carbon-based material may be p-doped”] wherein the conductivity type of the two-dimensional material layer is different from the conductivity type of the semiconductor layer.
Claim(s) 8, 9, 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Xu et al. (CN 104300029 A) hereafter referred to as Xu in view of Gruen et al. (US 20200381645 A1) hereafter referred to as Gruen
In regard to claim 8 Xu teaches an electromagnetic wave detector [see paragraph 0036 “As shown in FIG. 1, the present invention uses fluorinated graphene as avalanche photoelectric detector”] comprising:
a semiconductor [“n-type silicon substrate 1”] layer;
an insulating layer [“silicon dioxide isolation layer 2”] disposed on the semiconductor layer and having an [“silicon dioxide window 3”] opening;
a two-dimensional material layer [“graphene film 6”] extending from on the opening to on the insulating layer, including a connection part on a [see Fig. 1 graphene 6 extends from the opening , over the silicon dioxide and onto the top electrode 5] peripheral part of the insulating layer facing the opening, and electrically connected to [“fluorinated graphene insulating can be used as tunneling layer, forming metal-insulator-semiconductor (MIS) structure, reduces the dark current. good for improving the opening ratio of the detector and reduce the power consumption of the device”] the semiconductor layer;
a first electrode part [“top electrode 5”] disposed on the insulating layer and electrically connected to [see Fig. 1, see “the top electrode 5 on the upper surface and a fluorinated graphene surface on the insulating layer 4 covering the graphene film 6” see the electrical biasing in Fig. 1] the two-dimensional material layer;
a second electrode part [“the n-type silicon substrate 1 is arranged on the lower surface of the bottom electrode 7”] electrically connected to the semiconductor layer; and
the electromagnetic wave detector further comprises a tunnel layer [“graphene fluoride insulating layer 4”] having a first portion disposed between a part of the semiconductor layer [see Fig. 1 see “the fluorinated graphene insulating layer 4 surface uniformly coated a layer of polymethyl methacrylate (ΡΜΜΑ/ί) film, then putting into etching solution 4h etching to remove the copper foil, leaving graphene fluoride insulating layer supported by the PMMA 4, support of the PMMA fluorinated graphite insulating layer 4 with de-ionized water after cleaning is transferred to the upper surface of the top electrode 5. top electrode 5, silicon dioxide insulating layer 2 and η-type silicon substrate 1 surrounding the inner surface of the trapezoidal space formed”] positioned inside of the opening in a planar view and the two-dimensional material layer, and the two-dimensional material layer is electrically connected to the semiconductor layer by tunnel current [“fluorinated graphene insulating can be used as tunneling layer, forming metal-insulator-semiconductor (MIS) structure, reduces the dark current. good for improving the opening ratio of the detector and reduce the power consumption of the device”] flowing through the tunnel layer,
but does not teach
that the connection part is in contact with a peripheral part of the insulating layer,
a unipolar barrier layer disposed between the semiconductor layer and the connection part of the two-dimensional material layer and electrically connected to each of the semiconductor layer and the two-dimensional material layer, wherein the unipolar barrier layer has an annular portion disposed annularly in interior of the opening in a planar view,
that the first portion is disposed between a part of the semiconductor layer positioned inside of the annular portion in a planar view and the two-dimensional material layer.
The Examiner notes that a person of ordinary skill in the art is aware that graphene has a zero bandgap thus it is ambipolar.
See Gruen teaches contact doping of graphene, see paragraph 0038, 0048 “contact doping of graphene, lowering of cell series resistance, increasing work function differences and other matters pertaining to maximizing the performance parameters of the new generation of solar cells disclosed herein are detailed below. Further, while reference may be made to zinc oxide in many areas herein, it should be appreciated that other wide band-gap materials may be used in the alternative and/or in combination with zinc oxide in certain forms”, “nanowire cores may also include a variety of different materials. For example, a variety of wide bandgap materials may be used. Such wide bandgap materials may include, but are not limited to, zinc oxide, boron, titanium, silicon borides, carbides, nitrides, oxides, or sulfides, combinations thereof, and the like. Wide band-gap material will be understood to refer to a material having a valence band and a conduction band that differ by at least two volts. In one form, zinc oxide may be especially suitable for at least some of the techniques and combinations of materials discussed herein” “work function changes are due to a redistribution of charge that occurs when graphene comes into contact with ZnO, with the graphene interacting with ZnO in just the requisite manner, perhaps because its ambipolarity allows it to act as an electron acceptor” “the resulting large difference in work functions might make the graphene/ZnO junction favorable for charge separation” see paragraph 0074, 0085 “ZnO starts out as an n-type semiconductor, but when in contact with graphene material the ZnO transfers excess electrons to the graphene and the graphene becomes an n-type region that contains negatively charged electrons and ZnO becomes a p-type region that contains positive charge carriers. As is confirmed by experimental investigations presented in more detail below, the graphene coating absorbs photons of sunlight and a flow of electrons occurs from the graphene to the ZnO” “Charge separation occurs at the junction of graphene with ZnO yielding photocurrent at a cell voltage up to 2.4 V”.
The Examiner notes that the teaching of Gruen is essentially benefit of using a higher bandgap to interact with graphene.
The Examiner notes that in Xu Fig. 1 the portion of insulating 4 on silicon dioxide 2 does not further insulate graphene 6 because both insulating 4 and silicon dioxide 2 are both insulating, thus even if graphene 6 is in contact with silicon dioxide 2, it is still insulated.
See that in Xu Fig. 1 the graphene 6 is on the silicon dioxide 2 around the window 3 and separated by insulating 4, and that portion of silicon dioxide 2 is wasted space and can be replaced by suitable high bandgap material, and the area occupied by insulating 4 on the silicon dioxide 2 can be reduced and the tunnel insulating 4 is between the high band gap material and the graphene 6, in order to emulate the teachings of Gruen.
Thus, it 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 to modify Xu to add a high bandgap material to interact with graphene to affect work function i.e. to modify Xu to include that the connection part is in contact with a peripheral part of the insulating layer, a unipolar barrier layer disposed between the semiconductor layer and the connection part of the two-dimensional material layer and electrically connected to each of the semiconductor layer and the two-dimensional material layer, wherein the unipolar barrier layer has an annular portion disposed annularly in interior of the opening in a planar view, that the first portion is disposed between a part of the semiconductor layer positioned inside of the annular portion in a planar view and the two-dimensional material layer.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is to replace a portion of SiO2 window around the opening with a high bandgap material to interact with graphene to affect doping and work function and generate higher photoresponse output and ease of manufacture and simpler design by letting insulating 4 be smaller in area.
In regard to claim 9 Xu and Gruen as combined teaches wherein the tunnel layer further has a second portion [see combination claim 8 see that the tunnel insulating 4 is between the high band gap material and the graphene 6] disposed between the annular portion and the two-dimensional material layer.
In regard to claim 21 Xu and Gruen as combined teaches wherein a material forming the unipolar barrier layer [see Gruen teaches high bandgap oxide semiconductor] is oxide semiconductor.
Claim(s) 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Xu and Gruen as combined and further in view of An et al. (US 20150243826 A1) hereafter referred to as An
In regard to claim 21 Xu and Gruen as combined does not specifically teach an electromagnetic wave detector array comprising a plurality of the electromagnetic wave detectors according to claim 8 wherein the electromagnetic wave detectors are disposed to be aligned along at least one of a first direction and a second direction intersecting the first direction.
See An paragraph 0048 An teaches application of imaging, “the systems and devices described herein may be employed in infrared detectors and sensors, imaging devices”.
Thus, it 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 to modify Xu to include an electromagnetic wave detector array comprising a plurality of the electromagnetic wave detectors according to claim 8 wherein the electromagnetic wave detectors are disposed to be aligned along at least one of a first direction and a second direction intersecting the first direction.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is to perform work such as imaging.
Conclusion
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/SITARAMARAO S YECHURI/ Primary Examiner, Art Unit 2893