KR20180107557A - Method of manufacturing a graphene thin layer - Google Patents

Abstract

The present invention relates to a method for producing a graphene thin film. According to the present invention, the method for producing the graphene thin film comprises the following steps: (a) a step (S100) of forming a multilayer metal film (20) by sequentially coating a plurality of different metals having different carbon solubility on an upper surface of a substrate (10); (b) a step (S200) of injecting a plurality of carbon atoms (30) via an ion injection process on an upper surface of the multilayer metal film (20); (c) a step (S300) of annealing the multilayer metal film (20) injected with the carbon atoms (30) to disperse the carbon atoms (30) on the upper surface of the substrate (10) or the upper surface of the multilayer metal film (20); and (d) a step (S400) of cooling the annealed multilayer metal film (20) to form the graphene thin film (40) on the upper surface of the substrate (10) on which the carbon atoms (30) are dispersed, or on the upper surface of a second metal layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a graphene thin film manufacturing method,

The present invention relates to a method of manufacturing a graphene thin film, and more particularly, to a method of manufacturing a graphene thin film which forms a graphene thin film on a substrate.

Graphene is a thin-film material composed of carbon atoms, one atom thick, corresponding to one layer of graphite in which carbons are stacked in the form of a hexagonal honeycomb. Such graphene is utilized in various electric and electronic fields such as high-speed semiconductor, flexible display, and high-efficiency solar cell because of its excellent electric conductivity and thermal conductivity, fast mobility of electrons, and excellent elasticity with high strength.

Techniques for producing such graphene include mechanical peeling and chemical vapor deposition.

The mechanical peeling method is a technique of detaching graphene from graphite crystals by mechanical force as disclosed in the patent documents of the following prior art documents. This is possible because the electrons of the π-orbital of graphene have a smooth surface while spreading widely on the surface. However, according to the mechanical peeling method, there is a problem that the thickness of graphene can not be easily adjusted as desired.

On the other hand, the chemical vapor deposition method is a technique of synthesizing graphene using a transition metal which adsorbs carbon well at a high temperature as a catalyst layer, and has an advantage of producing graphene having excellent characteristics. However, since the transition metal is used as a catalyst layer, a process of transferring the graphene grown on the transition metal to a desired substrate is indispensably required. In addition, since the process is performed at a high temperature of about 800 to 1000 ° C., There are restrictions on the application to semiconductor processing and the electronics industry.

Accordingly, there is a desperate need for a solution to the problem of the conventional graphene manufacturing method.

KR 10-2013-0087018 A

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems of the prior art, and one aspect of the present invention is to provide a method of forming a graphene thin film by sequentially laminating metals having different carbon solubilities on a substrate, And to provide a method of manufacturing a graphene thin film which can manufacture graphene at a rapid and low process temperature.

The method of manufacturing a graphene thin film according to the present invention includes the steps of: (a) sequentially forming a plurality of different metals having different carbon solubilities on a substrate to form a multilayer metal film; (b) implanting a plurality of carbon atoms on an upper surface of the multilayer metal film in an ion implantation step; (c) annealing the carbon atom-implanted multilayer metal film to disperse the carbon atoms on the upper surface of the substrate or the upper surface of the multilayer metal film; And (d) cooling the annealed multilayer metal film to form a graphene thin film on the upper surface of the substrate on which the carbon atoms are dispersed in step (c), or on the upper surface of the multilayer metal film.

Further, in the method of manufacturing a graphene thin film according to the present invention, the carbon atoms are dispersed on the upper surface of the substrate so that the carbon solubility gradually decreases toward the upper part of the multilayer metal film, When the metal is laminated, the carbon atoms are dispersed on the upper surface of the multilayer metal film so that the carbon solubility increases gradually toward the upper part of the metal film.

Further, in the method of manufacturing a graphene thin film according to the present invention, when the graphene thin film is formed on the upper surface of the substrate, the method further comprises: removing the metal multilayer film, And transferring the graphene thin film to a transfer substrate when the thin film is formed.

In the method of manufacturing a graphene thin film according to the present invention, a step of performing pre-annealing at least once on the metal multi-layer film between the step (a) and the step (b) .

In the method of manufacturing a graphene thin film according to the present invention, at least one of the carbon ion implantation amount in the step (b), the annealing time in the step (c), and the cooling time in the step (d) , The thickness of the graphene thin film is adjusted.

In the method of manufacturing a graphene thin film according to the present invention, the plurality of metals are selected from the group consisting of nickel (Ni), silver (Ag), copper (Cu), and cobalt (Co).

Further, in the method of manufacturing a graphene thin film according to the present invention, one of the plurality of metals is cobalt.

In the method of manufacturing a graphene thin film according to the present invention, the thickness of each of the metal single layers formed by coating a plurality of the metals in the step (a) is 30 to 300 nm.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention, by sequentially laminating metals having different carbon solubilities on a substrate to form a multilayer metal film, introducing carbon atoms into the metal film, and inducing movement of carbon atoms in a direction of high carbon solubility, It is possible to control the formation position of the graphene film and form a graphene film on the substrate without a transfer process.

Further, by using a dissimilar metal, formation energy of graphene is lower than that in the case of using a single metal, so that high quality graphene can be produced at a rapid and low process temperature.

Furthermore, the thickness of the resulting graphene thin film can be easily controlled by controlling the amount of carbon ions injected, heat treatment, or cooling time.

1 is a process diagram of a graphene manufacturing method according to the present invention.
FIGS. 2 to 3 are process drawings showing, in cross section, the process of the method for producing graphene according to the present invention.
Figures 4 to 7 are Raman spectrum graphs of graphene.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms "first "," second ", and the like are used to distinguish one element from another element, and the element is not limited thereto. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a process diagram of a method of manufacturing a graphene according to the present invention, and FIGS. 2 to 3 are process drawings showing a process of a graphene manufacturing method according to the present invention.

As shown in FIGS. 1 and 2, the method of manufacturing a graphene thin film according to the present invention comprises the steps of: (a) sequentially coating a plurality of different metals having different carbon solubilities on a substrate 10, (B) implanting a plurality of carbon atoms 30 into the upper surface of the multi-layered metal film 20 by an ion implantation process (S200); (c) (S300) of dispersing carbon atoms (30) on the upper surface of the substrate (10) or the upper surface of the multilayer metal film (20) by annealing the multi-layered metal film (20) The annealed multilayered metal film 20 is cooled to form a graphene thin film 40 on the upper surface of the substrate 10 or the upper surface of the multilayered metal film 20 on which the carbon atoms 30 of the step (c) (S400).

The present invention relates to a method for producing a graphene thin film (40). Graphene is a material composed of a structure corresponding to one layer of graphite in which carbons are stacked in the form of hexagonal honeycomb, and has excellent electrical and thermal conductivity, fast electrons and high elasticity. It is used in the field. Conventional techniques for producing such graphenes include a mechanical peeling method in which graphene is removed by applying a mechanical force from a graphite crystal and a chemical vapor deposition method in which graphene is synthesized using a transition metal at a high temperature. However, according to the conventional graphene manufacturing technique, it is difficult to control the thickness of the graphene film. In particular, since the chemical vapor deposition technique requires a transfer process, the production process is slow and the process is performed only at a high temperature of 800 ° C or more. The present invention has been made in order to solve this problem.

The method of manufacturing a graphene thin film according to the present invention includes forming a multilayer metal film 20 (S100), injecting carbon atoms 30 (S200), annealing (S300), and cooling (S400).

First, in the step of forming the multilayer metal film 20, different metals are sequentially coated on the upper surface of the substrate 10 and laminated to form a multilayer metal film 20 (S100). Here, the substrate 10 may be a silicon substrate or a silicon oxide substrate, for example, a member on which a metal can be coated with a layered structure on the surface, and the type of the substrate 10 is not particularly limited.

A plurality of metals constituting the multilayer metal film 20 are used, each metal being individually coated to form a metal monolayer 21, 23, and the different metal monolayer 21, 23 is sequentially laminated To form a multi-layered metal film 20 in a bilayer or triple layer, or in multiple layers. Here, the metal may be deposited in an electron beam evaporation process using an e-beam evaporator, wherein the thickness of the metal monolayer 21, 23 is greater than the thickness of the carbon atoms 30 in an annealing step (S300) And 30 to 300 nm is preferable for diffusion. However, the thickness may be variable depending on the process conditions and the kind of the metal, and therefore, the thickness is not necessarily limited thereto.

Here, the order in which the metal monolayers 21 and 23 are laminated is based on the carbon solubility. Therefore, the plurality of metals must have different carbon solubility, and the metal monolayer 21, 23 is arranged in order of decreasing carbon solubility in the substrate 10 or in decreasing order of carbon solubility. That is, a structure in which different kinds of metals are sequentially stacked so that the carbon solubility gradually decreases toward the upper part of the multilayer metal film 20, or a structure in which different kinds of metals are sequentially deposited so as to increase the carbon solubility toward the upper part of the multilayer metal film 20. [ As shown in FIG. According to this structure, the formation position of the graphene thin film 40 is changed, which will be described later.

On the other hand, the different metals having different carbon solubilities can be selected from the group consisting of nickel (Ni), silver (Ag), copper (Cu), and cobalt (Co). Here, nickel or cobalt has a relatively high solubility in carbon, but copper has a low solubility in carbon. However, the different kinds of metals are not necessarily limited thereto, and various combinations can be made using other metals. At this time, any of the metals constituting the metal single layers 21 and 23 may be cobalt. Since cobalt has a low formation temperature of graphene, it can function to lower the graphene generation temperature.

When a multilayer metal film 20 is formed, a carbon atom 30 implantation step is performed (S200), where a plurality of carbon atoms 30 are implanted into the top surface of the multilayer metal film 20 through an ion implantation process. At this time, the multilayer metal film 20 acts as a catalyst in the process of manufacturing the graphene thin film 40, and by controlling the implantation amount of the carbon atoms 30 or the energy intensity of the ion implantation process, The thickness of the fin thin film 40 can be adjusted.

Next, in the annealing step, a heat treatment process is performed on the multi-layered metal film 20 into which the carbon atoms 30 are implanted (S300). At this time, the different metals constituting the multi-layered metal film 20 are alloyed, and the carbon atoms 30 move in different directions according to the difference in carbon solubility of the respective metals.

Concretely, in the case of the structure (i) in which the metal single layers 21 and 23 are arranged such that the carbon solubility gradually decreases toward the upper part of the multilayer metal film 20, the metal single layer 21 having the highest carbon solubility The carbon atoms 30 migrate and eventually disperse on the upper surface of the substrate 10. [

On the other hand, in the case of the structure (ii) in which the carbon solubility is gradually increased toward the upper part of the multilayer metal film 20, the carbon atoms 30 are formed on the surface of the outermost metal monolayer 23 having the highest carbon solubility, And is dispersed on the upper surface of the multilayer metal film 20.

In either case, the thickness and quality of the subsequently formed graphene film 40 can be adjusted by controlling the annealing temperature.

Finally, a cooling step is performed (S400). At this time, the graphene thin film 40 is formed at the position where the carbon atoms 30 are disposed. That is, during the cooling process, the carbon atoms 30 are mutually bonded to form the graphene thin film 40. On the other hand, in the cooling step, the thickness and quality of the graphene thin film 40 can be controlled by controlling the cooling time.

3, when the graphene thin film 40 is formed on the upper surface of the substrate 10 by the multilayered metal film 20 having the structure (i), the multilayered metal film 20 is formed, It is possible to form a high-quality graphene on the substrate 10 without a separate transfer step. Thus, the damage of the graphene thin film 40 caused in the transferring process is suppressed. At this time, the removal of the multilayer metal film 20 may be performed by etching or the like.

On the other hand, when the graphene film 40 is formed on the upper surface of the multilayer metal film 20 having the structure (ii), the graphene film 40 can be transferred using the transfer substrate 50 such as PMMA. Here, the transfer substrate 50 is a transfer object to which the graphene film 40 formed on the multilayer metal film 20 is transferred, and the material and material are not particularly limited.

Meanwhile, in the above-described embodiment of the present invention, a further preliminary annealing step may be further included between the forming step S100 of the multilayer metal film 20 and the step of injecting carbon atoms 30 (S200). Here, the preliminary annealing is repeated at least once, preferably about 1 to 3 times. However, the number of times of the preliminary annealing may be varied depending on the process conditions and the difference in materials, and therefore, the number of preliminary annealing is not limited thereto. When this preliminary annealing process is performed, the size of the grain boundary of the metal in the multilayer metal film 20 is reduced, and the uniformity of the surface of the metal monolayer 21, 23 is increased.

In general, according to the present invention, metals having different carbon solubility are successively laminated on a substrate 10 to form a multilayer metal film 20, carbon atoms 30 are injected into the metal film, carbon solubility The graphene film 40 can be formed on the substrate 10 without transferring the graphene film 40 by controlling the formation position of the graphene film 40 by inducing the movement of the carbon atoms 30 in a high direction. Further, by using a dissimilar metal, formation energy of graphene is lower than that in the case of using a single metal, so that high quality graphene can be produced at a rapid and low process temperature. Further, the amount of carbon ions implanted, heat treatment, The thickness and quality of the resulting graphene film 40 can be easily controlled.

Hereinafter, the present invention will be described with reference to specific examples.

Figures 4 to 7 are Raman spectrum graphs of graphene.

Example  1: a multilayer composed of silver, copper, and nickel Metal membrane  using Grapina  Thin film manufacturing

In the present embodiment, a multilayer metal film was produced by individually depositing silver, copper, and nickel on the substrate in an electron beam vaporization process to form a single layer. Then, carbon ions were injected into the multilayered metal film using an ion implantation process, followed by annealing and cooling. At this time, the generation time of the graphene film (high temperature holding time except for the temperature rise and the cooling time) was 5 minutes, 20 minutes and 30 minutes.

Example  2: silver, a multilayer of cobalt Metal membrane  using Grapina  Thin film manufacturing

In this embodiment, silver and cobalt were deposited to form a multi-layered metal film, and other processes were performed in the same manner as in Example 1 to produce a graphene thin film.

Comparative Example  1: Copper Single layer  using Grapina  Thin film manufacturing

In this comparative example, copper was deposited as a single layer on the substrate, carbon ions were implanted thereon by an ion implantation process, and annealed and cooled to form a graphene thin film. That is, this embodiment is the same as the first embodiment except that a copper single layer is used in comparison with the first embodiment.

Experimental Example  One: Grapina  Generation time analysis

Raman spectral analysis was carried out to determine the graphene generation time for Example 1 and Comparative Example 1.

As a result, in the case of Example 1, a graphene thin film was produced in all types of graphene thin films, that is, the graphene thin films were stably formed at a generation time of 5 minutes or more (see FIG. 4). However, in the case of Comparative Example 1, graphene was produced only when the generation time was 30 minutes or more (see FIG. 5).

Therefore, it can be confirmed that the time required for forming the graphene thin film is shortened when the multilayer metal film is used as the catalyst layer according to the present invention.

Experimental Example  2: Grapina  Generation temperature

Raman spectral analysis was carried out for Example 2 and Comparative Example 2 in order to grasp the graphene generation temperature.

As a result, in the case of Example 2 including cobalt, graphene was produced from a production temperature of 500 ° C or higher (see FIG. 6), but in Comparative Example 1, graphene was produced only above 750 ° C (see FIG. 7).

Therefore, in the method of manufacturing a graphene thin film according to the present invention, when a multilayer metal film including cobalt as a single metal layer is used, the production temperature can be relatively lower than that in the case of using a metal other than cobalt as a single layer Able to know.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification or improvement is possible.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: substrate 20: multilayer metal film
21, 23: metal single layer 30: carbon atom
40: Graphene thin film 50: Transfer substrate

Claims (8)

(a) sequentially coating a plurality of different metals having different carbon solubilities on an upper surface of a substrate to form a multilayer metal film;
(b) implanting a plurality of carbon atoms on an upper surface of the multilayer metal film in an ion implantation step;
(c) annealing the carbon atom-implanted multilayer metal film to disperse the carbon atoms on the upper surface of the substrate or the upper surface of the multilayer metal film; And
(d) cooling the annealed multilayer metal film to form a graphene thin film on the upper surface of the substrate on which the carbon atoms are dispersed in step (c), or on the upper surface of the multilayer metal film;
Wherein the graphene thin film is formed on the substrate.
The method according to claim 1,
The carbon atoms are dispersed on the upper surface of the substrate so that the carbon solubility gradually decreases toward the upper part of the multilayer metal film,
Wherein the carbon atoms are dispersed on the upper surface of the multilayer metal film so that carbon solubility increases gradually toward the upper portion of the multilayer metal film when the metals are stacked.
The method according to claim 1,
And removing the metal multilayer film when the graphene thin film is formed on the upper surface of the substrate,
And transferring the graphene thin film to a transfer substrate when the graphene thin film is formed on the upper surface of the metal multilayer film.
The method according to claim 1,
Performing at least one pre-annealing on the metal multi-layer film between the step (a) and the step (b);
Wherein the graphene thin film is formed on the substrate.
The method according to claim 1,
The graphene thin film is manufactured by adjusting the thickness of the graphene thin film by controlling at least one of the carbon ion implantation amount in the step (b), the annealing time in the step (c), and the cooling time in the step (d) Way.
The method according to claim 1,
Wherein the plurality of metals are selected from the group consisting of nickel (Ni), silver (Ag), copper (Cu), and cobalt (Co).
The method according to claim 1,
Wherein one of the plurality of metals is cobalt.
The method according to claim 1,
In the step (a), the thickness of each of the metal single layers formed by coating each of the plurality of the metals is 30 to 300 nm.

Images