# US 2021/0242314 A1 · Methods of manufacturing a graphene-based device

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- Number: US 2021/0242314 A1
- Document ID: US20210242314A1
- Status: Published application
- Kind: A1
- Application number: 16/972,545
- Filed: 2019-06-04
- Published: 2021-08-05
- Earliest claimed: 2018-06-05
- Applicants: The University of Manchester
- Inventors: Max MIGLIORATO; Rakesh KUMAR; Umberto MONTEVERDE
- Web page: https://patentgrep.com/patent/US20210242314A1

## CPC

- H10D 62/882: {Graphene}
- C01B 32/186: by chemical vapour deposition [CVD]
- C30B 25/22: Sandwich processes
- G01N 27/4146: {involving nanosized elements, e.g. nanotubes, nanowires}
- H10P 14/3406: {Carbon, e.g. diamond-like carbon}
- H10P 90/1914: {using bonding}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

A method of manufacturing a graphene-baseddevice, comprising (i) providing a graphene assembly comprising one or more layers of graphene, a first photoresist layer disposed on the one or more layers of graphene, and an ultra-violet (UV) barrier layer disposed on the photoresist layer on an opposite side to the one or more layers of graphene; (ii) transferring the graphene assembly onto a substrate comprising at least one cavity so that the one or more layers of graphene traverse the at least one cavity; (iii) using photolithography to expose portions of the one or morelayers of graphene on opposite sides of the at least one cavity;(iv) forming conductive contacts over the exposed portions of graphene; (v) removing the UV barrier layer; and (vi) removing the first photoresist layer.

## Claims

### Claim 1

A method of manufacturing a graphene-based device, comprising:
providing a graphene assembly comprising one or more layers of graphene, a first photoresist layer disposed on the one or more layers of graphene, and an ultra-violet (UV) barrier layer disposed on the first photoresist layer on an opposite side to the one or more layers of graphene;
transferring the graphene assembly onto a substrate comprising at least one cavity so that the one or more layers of graphene traverse the at least one cavity;
using photolithography to expose portions of the one or more layers of graphene on opposite sides of the at least one cavity;
forming conductive contacts over the exposed portions of graphene;
removing the UV barrier layer; and
removing the first photoresist layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the UV barrier layer comprises aluminium, gold, silver or chromium.

### Claim 3 (depends on 1)

The method of claim 1, wherein providing the graphene assembly comprises providing a precursor graphene assembly, wherein the precursor graphene assembly comprises the graphene assembly and a layer of copper disposed on a side of the one or more layers of graphene that is opposite to the first photoresist layer, and wherein the layer of copper is removed to provide the graphene assembly.

### Claim 4

(canceled)

### Claim 5 (depends on 3)

The method of claim 3, wherein the precursor graphene assembly further comprises one or more sacrificial layers of graphene disposed on a side of the layer of copper that is opposite the one or more layers of graphene, and wherein the method further comprises removing the one or more sacrificial layers of graphene prior to removing the layer of copper.

### Claim 6

(canceled)

### Claim 7 (depends on 1)

The method of any preceding claim 1, wherein the substrate comprises of Si, SiO2, or SU8 polymer.

### Claim 8 (depends on 1)

The method of any preceding claim 1, wherein using photolithography to expose portions of the graphene on opposite sides of the at least one cavity comprises disposing a second photoresist layer on the UV barrier layer, using a photomask to lithographically pattern the second photoresist layer so that second photoresist layer remains on the UV barrier layer whilst exposing portions of the UV barrier layer on opposite sides of the at least one cavity, removing the exposed portions of the UV barrier layer so as to expose portions of the first photoresist layer on opposite sides of the at least one cavity and leave remaining UV barrier layer traversing therebetween, removing the exposed portions of the first photoresist layer so as to expose the portions of the one or more layers of graphene and leave remaining first photoresist layer traversing therebetween.

### Claim at position 9

-11. (canceled)

### Claim 12 (depends on 1)

The method of claim 1, wherein forming conductive contacts comprises depositing conductive material onto the exposed portions of graphene by thermal evaporation, and wherein the conductive material comprises a layer of a first conductive material and a layer of a second conductive material.

### Claim 13 (depends on 12)

The method of claim 12, wherein the first conductive material comprises Cr and/or wherein the second conductive material comprises Au.

### Claim 14 (depends on 8)

The method of claim 8, wherein forming conductive contacts comprises depositing conductive material onto the exposed portions of graphene by thermal evaporation, and the method further comprises using a third photoresist layer to mask the conductive material deposited on the exposed potions of graphene, removing any other deposited conductive material, and lithographically removing the third photoresist layer prior to removing the UV barrier layer.

### Claim at position 13

-20. (canceled)

### Claim 21 (depends on 1)

The method of claim 1, wherein the at least one cavity is a single cavity or an array of adjacent cavities.

### Claim 22

A method of manufacturing a graphene-based device, comprising:
providing a graphene assembly comprising one or more layers of graphene, and a first photoresist layer disposed on the one or more layers of graphene, transferring the graphene assembly onto a substrate comprising at least one cavity so that the one or more layers of graphene traverse the at least one cavity;
transferring the graphene assembly onto a substrate comprising at least one cavity so that the one or more layers of graphene traverse the at least one cavity;
using photolithography to expose portions of the graphene on opposite sides of the at least one cavity;
forming conductive contacts over the exposed portions of graphene; and
removing the first photoresist layer;
wherein removing the first photoresist layer comprises using critical point drying or immersing the device in a solvent which is then replaced with a low surface tension solvent.

### Claim 23 (depends on 22)

The method of claim 22, wherein providing the graphene assembly comprises providing a precursor graphene assembly, wherein the precursor graphene assembly comprises the graphene assembly and a layer of copper disposed on a side of the one or more layers of graphene that is opposite to the first photoresist layer, and wherein the layer of copper is removed to provide the graphene assembly.

### Claim at position 17

-26. (canceled)

### Claim 27 (depends on 22)

The method of claim 22, wherein the substrate comprises of Si, SiO2, or SU8 polymer.

### Claim 28 (depends on 22)

The method of claim 22, wherein using photolithography to expose portions of the graphene on opposite sides of the at least one cavity comprises disposing a second photoresist layer on the UV barrier layer, using a photomask to lithographically pattern the first photoresist layer so as to expose the portions of the one or more layers of graphene and leave remaining first photoresist layer traversing therebetween.

### Claim 29

(canceled)

### Claim 30 (depends on 28)

The method of claim 28, wherein forming conductive contacts comprises depositing conductive material onto the exposed portions of trraphene by thermal evaporation, and wherein the conductive material comprises a layer of a first conductive material and a layer of a second conductive material.

### Claim 31

(canceled)

### Claim 32 (depends on 28)

The method of claim 28, wherein forming conductive contacts comprises depositing. conductive material onto the exposed portions of graphene by thermal evaporation, and the method further comprises using a further photoresist layer to mask the conductive material deposited on the exposed potions of graphene, removing any other deposited conductive material, and lithographically removing the further photoresist layer.

### Claim at position 24

-35. (canceled)

### Claim 36 (depends on 22)

The method of claim 22, wherein the at least one cavity is a single cavity or an array of adjacent cavities.

### Claim 37

(canceled)

### Claim 38

A graphene-based device comprising:
a substrate comprising a plurality of cavities;
a plurality of layers of graphene, wherein each layer of graphene is disposed on the substrate and traverses at least one of the plurality of cavities; and
electrical contacts comprising conductive material disposed on the layers of graphene on opposite sides of each of the plurality of cavities.

### Claim 39 (depends on 38)

The graphene-based devices according to claim 38, wherein the graphene-hased device forms part of a gas sensor.

### Claim 40 (depends on 1)

The method of claim 1, wherein removing the first photoresist layer comprises (a) using critical point drying, or (b) immersing the device in a solvent which is then replaced with a low surface tension solvent.