KR20170035323A - Preparation Method of Graphene Thin Film Layer without Transferring - Google Patents

Abstract

The present invention relates to a preparation method of a graphene thin film layer and an electric element having a graphene thin film layer formed thereby, which can easily form a high quality graphene thin film layer having excellent crystallizability without transferring in a large area at a low temperature. Therefore, the graphene thin film layer can be directly applied to a base substrate used for a transparent electrode or a semiconductor element without an additional transferring process. More specifically, the present invention relates to a preparation method of a graphene thin film layer without transferring, which comprises the following steps of: depositing a Ti layer having a thickness of 3-20 nm by sputtering on a substrate; and growing graphene by a chemical vapor deposition on the deposited Ti layer.

Description

Preparation Method of Graphene Thin Film Layer without Transferring < RTI ID = 0.0 >

The present invention relates to a graphene layer which can be easily applied to a base substrate used for a transparent electrode or a semiconductor device without a separate transferring process and which can easily form a high-quality graphene layer having excellent crystallinity in a non- A method of forming a pinned layer and a graphene layer formed by the method.

Graphene is a two-dimensional, hexagonal sp ² complex of carbon atoms with physical strength greater than 200 times that of steel. It has 10 times more thermal conductivity than metals such as copper and aluminum, has very high mobility of electrons, has a resistance lower than 35% at copper at room temperature, exhibits anomalous hall effect at room temperature, Electrical properties are reported. Due to these characteristics, researches on the manufacture of high quality graphene and application of devices have been actively carried out.

Graphene can be largely manufactured by four methods of mechanical peeling, chemical preparation using a reducing agent, epitaxial method using silicon carbide insulator, and chemical vapor deposition (CVD).

The first representative recipe to be introduced is to produce graphene from highly ordered pyrolytic graphite (HOPG) using a very delicate mechanical exfoliation technique. The mechanical exfoliation method has played a crucial role in rapidly diffusing graphene research due to the simplicity of sample preparation, but its size is only micrometer level and there are many limitations in practical application.

In order to produce a large area graphene, a bulk graphite (HOPG) is chemically peeled off in a liquid phase using a strong acid to prepare a graphene oxide film, and the graphene oxide film is transferred to a base substrate and then subjected to chemical reduction A method of reduction to graphene is being studied. However, crystal defects may occur during the oxidation or reduction of graphene, which may deteriorate electrical characteristics.

The epitaxial process is the adsorption of crystals at high temperatures or the carbon contained therein grows into graphene along the grain surface. For example, epitaxial graphene can be produced by vacuum heat treatment on a SiC (0001) substrate. According to this method, a graphene film of about the size of a wafer can be manufactured, but there is a problem that the base substrate is limited to an expensive SiC (0001) substrate.

Recently, a technique for producing graphene on a catalyst metal such as nickel or copper using a chemical vapor deposition method using methane gas has been developed. According to the chemical vapor deposition method, it is possible to control the number of graphene layers by controlling the type and thickness of the catalyst, the reaction time, and the concentration of the reaction gas. In addition, the characteristics of the graphene produced are excellent and mass production is possible.

However, when the graphene layer is formed by the chemical vapor deposition method, the nickel or copper catalyst layer formed for the deposition of the graphene layer changes the electrical and optical characteristics of the base substrate on which the graphene layer is formed, I am crazy. In addition, since deposition at a high temperature of about 1000 ° C. is generally performed for crystallization of graphene, when the base substrate is weak against heat, deformation of the base substrate may occur during the deposition process. Therefore, in order to use the graphene layer formed by the chemical vapor deposition method in an actual electrode or device, a transferring process in which the graphene layer grown on the catalytic metal is peeled off and transferred onto a desired base substrate is essential.

Generally, a method of transferring graphene is a method in which a graphene layer is formed on a catalyst metal, polymethylsiloxane (PDMS) or polymethylmethacylate (PMMA) is used as a support layer to etch and remove the catalyst metal, Thereby removing the post support layer. However, due to the mechanical deformation (wrinkle, ripple, etc.) of graphene in the transfer process, many defect levels are formed at the interface between the transferred graphene layer and the base substrate, There is a problem that it becomes poor.

In order to solve the problem of the graphene layer forming method by the chemical vapor deposition method, various methods for increasing the transfer success rate have been developed. The inventors of the present invention have also confirmed that when graphene is transferred onto a Ti thin film, the mechanical deformation of the graphene is minimized during the transfer of the graphene, thereby maintaining excellent electrical characteristics of the graphene, and this has been registered as a patent No. 10-1475460.

However, a more fundamental problem-solving method is to develop a method of forming a graphene layer that does not require a transfer process.

For this purpose, the introduction of the metal layer necessary for the formation of the graphene layer by the chemical vapor deposition method should not affect the electrical and optical characteristics of the base substrate. However, no results have been reported.

Even if the electrical and optical characteristics of the base substrate are not affected, low-temperature deposition must be possible in order to directly form a graphene layer on a flexible substrate, which is recently attracted by the base substrate of a semiconductor device. Rafik Addou et al. Reported that a graphene layer can be formed by chemical vapor deposition even at a low temperature of about 550 ° C. when nickel is used as a catalyst. However, at 500 ° C. or lower, carbide formed on the surface of the nickel layer causes graphene growth At the same time. Polyimide is the most widely used base material for flexible devices. It has a glass transition temperature of about 300 ° C. Among them, kapton polyimide is thermally stable up to 400 ° C and is applicable to relatively high temperature processes. However, in order to form a graphene layer, not only the process temperature is high but also the cost is high and the economical efficiency is low to apply the chemical vapor deposition method to the polyimide-based synthetic resin as the base substrate. Therefore, in addition to the development of heat-resistant flexible base substrate, it is possible to produce a flexible base substrate which is low in price but weak in heat and flexible to be applied to a base substrate, such as polyethylene (PE), polyethylene terephthalate (PET), polycarbonate (PC), polyether sulfone It is strongly required to lower the processing temperature so as to be applicable.

Registration No. 10-1475460

Rafik Addou et al., Applied Physics Letters 100, 021601, 2012

It is an object of the present invention to provide a method of manufacturing a semiconductor device which does not require a separate transfer process by a pretreatment process that can promote the growth of graphene without changing the electrical and optical characteristics of the base substrate, It is another object of the present invention to provide a method for forming a high-quality graphene layer having excellent crystallinity directly on a large area.

Another object of the present invention is to provide a method capable of forming a graphene layer excellent in crystallinity even at a low temperature of 400 캜, more preferably less than 300 캜.

Another object of the present invention is to provide an electrical device comprising the graphene layer produced by the above method.

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: depositing a Ti layer having a thickness of 3 to 20 nm on a base substrate by sputtering; and growing graphene on the deposited Ti layer by chemical vapor deposition And a method of forming the electroless graphene layer.

In the present invention, the term "base substrate" refers to a substrate on which a graphene layer such as a transparent electrode or a semiconductor device is to be formed, and a graphene layer is finally transferred in a graphene layer formation method including a conventional transfer process. That is, in the present invention, since the graphene layer is directly grown on the substrate on which the graphene layer is to be finally formed, the transfer process is not required. In the present invention, the base substrate is not limited to the material and the shape, and may be a single layer substrate or a substrate in which other materials are stacked. Materials such as glass, metal oxide, SiO ₂ , polyethylene terephthalate (PET) containing oxygen in the structure, polyether sulfone (PES), polycarbonate (PC) Ti is more preferable as a base substrate since it strongly bonds with the base substrate. However, in the present invention, graphene can be grown by chemical vapor deposition (CVD) without changing the characteristics of the base substrate by forming a 3 to 20 nm Ti layer on the base substrate. Therefore, It does not have to be.

As disclosed in Korean Patent No. 10-1475460 of the present inventors, Ti forms a Ti oxide even when subjected to physical vapor deposition (PVD) and chemically bonds with oxygen derived from the substrate and strongly binds to the substrate. The present inventors expect that graphene bonds strongly due to binding of oxygen and Ti present in the mechanically peeled graphene, and confirmed that the graphene is bound strongly, and it is confirmed in the registered patent No. 10-1475460. The present invention can further grow graphene by a chemical vapor deposition method directly on a base substrate surface-modified with Ti, without catalyst metal such as nickel or copper, so as to omit the transcription process causing mechanical defects And the results are confirmed by experiments.

The transmittance of the glass substrate on which the Ti layer was deposited was measured by a UV-Vis spectrophotometer according to the thickness of the Ti layer. As a result, when the thickness of the Ti layer was 20 nm or less, the transmittance of the glass substrate was almost the same And then the transmittance rapidly decreased as the thickness of the Ti layer increased. The sheet resistance of the Ti (20 nm) / glass is about 2.3 × 10 ⁹ Ω / Ω, which is almost similar to the sheet resistance of glass of 2.4 × 10 ⁹ Ω /. The Ti layer below 20 nm has almost no effect on the conductivity of the substrate there was. Therefore, when the thickness of the Ti layer deposited on the base substrate is 3 to 20 nm, only the surface properties can be modified without substantially affecting the electrical and optical characteristics of the base substrate itself such as transmittance and conductivity. Further, if the base substrate is made of a transparent and flexible material such as PET, the transparency and flexibility of the graphene can be maintained even after transferring the graphene.

The temperature of the substrate during the growth of graphene by the chemical vapor deposition method may be from 150 to 900 캜. If the other reaction conditions are the same, the higher the temperature, the better the crystallinity of the graphene. Therefore, even if the temperature is higher than 900 ° C., the higher the temperature, the higher the manufacturing cost.

Particularly, according to the present invention, a graphene layer having excellent crystallinity can be formed even when the temperature of the substrate is 150 to 400 ° C during the growth of graphene by a chemical vapor deposition method. According to the prior art, even when a metal catalyst layer such as nickel or copper is used, deposition can be performed at a temperature of 400 ° C or less by chemical vapor deposition. Therefore, the capton polyimide, which is known to be heat stable up to about 400 ° C, The graphene layer can be directly formed on the substrate by the electroless method. Further, the method of the present invention can form a high-quality graphene layer even at a temperature of 150 ° C or more and less than 300 ° C. Kapton polyimide is widely used in flexible substrates because it is relatively heat resistant, but it is expensive, and polyethylene, polyethylene terephthalate, polycarbonate, Polymer resins such as polyethersulfone are inexpensive, but are weak to heat, so they are deformed due to the manufacturing process of flexible substrates and their use is limited. However, the present invention was able to form a graphene layer even at a low temperature of 150 DEG C, and the graphene characteristics measured on the Raman spectrum were also excellent. In order to form a good quality graphene layer at a temperature of 150 to 400 ° C, it is more preferable that the working pressure during the growth of graphene by chemical vapor deposition is 10 mTorr or less.

The crystallinity of the formed graphene layer could be further controlled by the working pressure, the composition of the reaction gas and the flow rate.

As the reaction gas for growth of graphene, at least one gas selected from the group consisting of methane, ethane, propane, acetylene, methanol, ethanol and propanol can be used as the carbon source. In addition, the reaction gas may be supplied with a stable gas such as argon or helium as an atmospheric gas to grow graphene. However, in order to prevent the process pressure from being increased while increasing the concentration of carbon source, Is preferably used. It is further preferable to inject a mixture of hydrogen gas and carbon gas into the reaction gas in order to prevent the oxidation reaction in the reaction.

It has been reported that bonds such as C = O and C-OH exist in graphene produced by chemical vapor deposition. The graphene-derived oxygen is expected to contribute to the stabilization of graphene deposited by bonding with Ti. Since the graphene can not be stabilized when the Ti layer formed on the base substrate is bound to oxygen in the air and is present as titanium oxide, it is possible to remove the oxide film of the Ti layer by reduction before the deposition of the graphene in the present invention As shown in Fig. The removal of the oxide film can be achieved by treating the Ti with hydrogen gas in a heated state, but is not limited thereto. In the following examples, it was confirmed that the treatment of Ti with hydrogen gas increased the growth area of graphene and improved the crystalline properties of graphene.

According to the method of the present invention, since the grains are directly grown on the substrate after the Ti thin film is deposited without changing the transparency or the conductivity of the base substrate, a transfer process is unnecessary and thus, there is a concern about the occurrence of mechanical defects in the transfer process There is no. Even if a pattern of graphene is desired to be formed on a substrate, it is possible to easily form a pattern even if there is no additional process such as etching by forming masking when depositing titanium or graphene.

The present invention is also produced by the above method, comprising: a base substrate; A 3 to 20 nm thick Ti layer deposited by sputtering on a base substrate; And a graphene layer deposited on the Ti layer by a chemical vapor deposition method. Since the graphene is directly grown on the substrate by a chemical vapor deposition method without a separate transfer process, the substrate is minimized in mechanical defects and exhibits more stable electrical characteristics due to its excellent electrical characteristics.

It is a matter of course that all the devices to which the conventional graphene junction device is applied include the electric device. That is, all of the components using graphene as electrodes are examples of the electric device, and examples thereof include, but are not limited to, an electrode material of a capacitor, a display, an organic field effect transistor, a solar cell, and an LED.

As described above, according to the method of forming a graphene layer of the present invention, graphene can be grown directly on a substrate by surface modification with a Ti thin film without changing the transparency and electrical characteristics of the base substrate, Mechanical defects of graphene are minimized and can be used to manufacture high quality graphene electrical devices.

In addition, according to the method of the present invention, since graphene having excellent crystallinity can be grown even at a low temperature of 400 ° C or lower, particularly 150 ° C, a flexible substrate of a polymeric material such as PET is used as a base substrate, It is possible to grow directly, and since graphene is strongly bonded to graphene by bonding of oxygen and Ti layer derived from graphene and bonding of Ti layer and oxygen derived from substrate in the growth process of graphene, The present invention can be more effectively utilized for a flexible electric device that receives a flexible electric device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simulation result of adsorption positional analysis of carbon on titanium surface. FIG.
Figure 2 shows a simulation result of the activation energy required for the surface diffusion of carbon at the titanium surface.
Figure 3 is a thermodynamic analysis simulation result for C6 ring formation and graphene layer formation.
Fig. 4 is a simulation result showing that a complete Ti-C lattice matching is performed on a Ti (0001) substrate to grow graphene.
5 is a schematic diagram of a 3-zone furnace used in chemical vapor deposition in an embodiment of the present invention.
FIG. 6 is a Raman spectrum showing the growth characteristics of graphene according to an embodiment of the present invention. FIG.
FIG. 7 is a Raman spectrum illustrating the growth characteristics of graphene according to the deposition conditions according to an embodiment of the present invention. FIG.
8 is a Raman spectrum and graph showing the growth characteristics of graphene according to working pressure.
Figure 9 is a Raman spectrum and graph showing the growth characteristics of graphene over time of hydrogen treatment.
10 is a Raman spectrum and a graph showing the growth characteristics of graphene according to the inflow amount of hydrogen gas in the reaction gas.
11 is a Raman spectrum and graph showing the growth characteristics of graphene according to methane gas inflow in the reaction gas.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, these embodiments are merely examples for explaining the content and scope of the technical idea of the present invention, and thus the technical scope of the present invention is not limited or changed. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention based on these examples.

[Example]

Example 1: Simulation of graphene growth on Ti surface based on density function theory

The growth of graphene due to adsorption and surface diffusion of carbon on the Ti (0001) crystal structure surface was simulated based on density functional theory (DFT).

More specifically, a projector-augmented-wave (PAW) method [Phys. Rev. B 50, 1795317979 (1994)], which is based on the density function theory in the Vienna Ab-initio Simulation Package (VASP) [Phys. Rev. B 54, 1116911186 (1996)). The exchange correlation energy function is determined by the Perdew-Burke-Ernzerhof (PBE) method [Phys. Rev. Lett. 77, 38653868 (1996)) with a kinetic energy cut-off of 400 eV. The electron density function calculation for grafting of graphene and Ti was carried out using three layers of titanium layers arranged in the direction of Ti (0001) with a size of 5 × 5 carbon atoms of 72 carbon atoms. In this case, 37 oxygen atoms were gradually adsorbed on the titanium to oxidize the titanium.

1) Simulation of adsorption sites of carbon atoms on titanium surface

First, the binding energy (E _bind ) of carbon atoms adsorbed on the titanium surface was simulated for each adsorption position, and the results are shown in FIG. In Fig. 1, gray represents a titanium atom and yellow represents a carbon atom. The bond energy is expressed as the difference between the sum of the ground state energy of the carbon atom adsorbed on the titanium surface and the ground state energy of each of the titanium surface and the carbon atom. As shown in FIG. 1, it can be confirmed that the FCC site is the most preferred site for adsorption of carbon atoms with the binding energy of -8.22 eV / C atom at the FCC site where the three titanium atoms are gathered in a triangular form and the lower titanium layer is located . This means that when graphene is formed on the titanium surface, the carbon atoms can be located at the titanium FCC point and the Ti-C atoms are morphologically well matched.

2) Simulation of graphene growth by surface diffusion of carbon on titanium surface

The surface diffusion of carbon on the titanium surface was simulated by DFT calculation. FIG. 2 shows the calculation of the activation energy required for the surface diffusion of carbon on the titanium surface, indicating that a minimum activation energy of 0.26 eV and a maximum of 0.56 eV is required depending on the diffused position. Table 1 shows the results of simulating the surface diffusion rate of carbon with the deposition temperature in the case of diffusion with activation energy of 0.56 eV. In Table 1, the surface diffusion rate of carbon at 300 K is 3.91 × 10 ² / sec, which means that carbon can diffuse the surface of titanium even at low temperatures if the amount of carbon is sufficient.

Figure 3 shows the results of a thermodynamic analysis simulation of C6 ring formation and graphene layer formation through DFT calculation. Assuming that a sufficient amount of carbon is present and sufficient time for diffusion is given, the carbon atoms adsorb to the FCC point on the surface of the titanium layer and form the C6 ring by surface diffusion. The formation energy (E _form ) of the C6 ring indicates that the C6 ring formed with a total of -1.66 eV is in a stable state. Since the C6 ring acts as nuclei for growth and the formation energy gradually decreases as graphene grows, it can be confirmed that it can grow into large area graphene through continuous supply and diffusion of C. Figure 4 shows a simulation result of graphene growth where a complete Ti-C lattice match is achieved on a Ti (0001) substrate given a sufficient amount of C and sufficient time.

Example 2: Growth of a graphene layer through a titanium layer

1) Deposition of Ti by sputtering

Ti was deposited on the base substrate by sputtering to modify the surface of the substrate. That is, SiO ₂ (250 nm) / Si substrate or PET (polyethylene terephthalate, thickness: 100 μm) substrate was washed as a base substrate and N 2 gas was used to remove foreign substances on the surface. Ti was deposited at room temperature using a dc sputtering method using a 2-inch diameter Ti metal target (purity 99.99%). The working pressure was maintained at 0.13 Pa, 20 sccm (standard cc / min) of Ar gas was used as the sputtering gas, and a dc power of 20 W was applied to the Ti target to form a Ti thin film of 10 nm at a deposition rate of 1.5 nm / Respectively.

2) Characterization of graphene by graphene growth temperature

(10 nm) / SiO ₂ (250 nm) / Si substrate prepared in 1) by rapid thermal pulse chemical vapor deposition (T-CVD) using the 3-zone furnace shown in FIG. 5 To form a graphene layer. In the 3-zone furnace, there is a heating device at the inlet side where the reaction gas is introduced, and C atoms are generated by pyrolysis of the reaction gas. Since the furnace is heated only at the beginning of the furnace, the temperature decreases as the furnace moves away from the inlet, so the reaction temperature can be controlled by the position of the substrate. For example, a heat-resistant substrate such as a Si substrate or glass is placed in a high temperature region or a middle temperature region, and a substrate having a low thermal stability such as a flexible substrate made of a polymer material is placed in a low temperature region, Can be adjusted.

To confirm the growth of graphene on the Ti layer, CH ₄ : H ₂ = 50: 50 sccm was flowed as a reaction gas, and CH ₄ gas was decomposed at a process temperature of 1000 ° C at a rate of 5 ° C / min. In order to remove the surface oxide film of Ti, H ₂ gas of 50 sccm was flowed during the temperature rise time. The deposition pressure was maintained at 200 mTorr and deposition was carried out at 900, 800, 400 and 150 ° C for 2 hours, respectively, by adjusting the position of the substrate.

The Raman spectrum was measured to confirm that graphenes were grown on the substrate produced by the above method, and the results are shown in FIG. As shown in FIG. 6, graphene does not grow at a low temperature of 150 ° C., but G peak and 2D peak exist at a temperature of 400 ° C. or higher, indicating that graphene can grow on a Ti layer at a high temperature without nickel or copper catalyst metal Respectively. Especially, graphene was formed at 400 ℃, which confirmed the possibility of low - temperature growth. The G peak, which is formed at about 1581 cm ^-1 , shows that the graphene grown on the Ti layer has excellent crystallinity, and the 2D peak formed at about 2704 cm ^-1 without sharp shift C was deposited on the Ti layer as graphene instead of graphite.

Example 3: Low temperature growth and characterization of graphene

In order to grow graphene on a polymer substrate such as a flexible substrate having low thermal stability, it is essential to grow at a low temperature. Thus, the growth characteristics of graphene by deposition conditions were evaluated to confirm the possibility of low temperature growth of graphene.

(10 nm) / PET substrate fabricated according to the method described in 1) of Example 2 was used to grow graphenes on a transparent and flexible PET substrate by thermal chemical vapor deposition (T-CVD) in the same manner as in 2) , thermal chemical vapor deposition) method. The CH ₄ gas was decomposed at a process temperature of 1100 ° C at a rate of 5 ° C / min. In order to remove the surface oxide film of Ti, a flow rate of 50 sccm of H ₂ gas was applied during the temperature rise time. During the reaction time, the deposition temperature was maintained at 150 ° C and the deposition pressure was maintained at 300 mTorr. The composition and flow rate of the reaction gas were adjusted to CH ₄ : H ₂ = 60: 150, 100: 200, or 200: 100 sccm, Lt; / RTI >

Figure 7 is the Raman spectrum of C deposited on the Ti layer by the above method. 7, it can be seen that graphene is not generated under the growth temperature of 150 ° C and CH ₄ : H ₂ = 60: 150. However, as the ratio with the flow rate of CH ₄ increases CH _4: H ₂ = 100: Although Although accompanied by a shift of the peak in the 200 condition G, have determined the generation of the 2D peak, yes albeit crystallinity and quality of the pin, but Indicating that graphene was grown on the substrate. CH ₄ ratio and which further increase the flow rate of CH _4: H ₂ = 200: The graphene growth under the conditions of 100 was confirmed that has excellent crystallinity through the G peak, which is formed in the sharp at ~ 1582 cm ^-1 It was confirmed that the C pyrolyzed by the above method at a low temperature was grown on the Ti layer of the PET polymer substrate as graphene instead of graphite, through the 2D peak formed at ~ 2704 cm ^-1 without shift at a temperature of ~ 2704 cm ^-1 .

The effect of graphene growth on the growth of graphene was investigated in order to form a graphene layer with excellent crystallinity even at low temperatures.

1) Evaluation of growth characteristics of graphene according to working pressure

Graphene was grown in the same manner as in 2) using a Ti (10 nm) / SiO ₂ / Si substrate produced according to the method described in 1) of Example 2. CH ₄ gas was decomposed at a process temperature of 1100 ° C at a rate of 5 ° C / min. In order to remove the surface oxide film of Ti, 10 sccm of H ₂ gas was flown at 750 ° C for 240 minutes during the temperature rise time. During the reaction time, the deposition temperature was maintained at 150 ° C and the composition and flow rate of the reaction gas were flowed at a ratio of CH ₄ : H ₂ = 1: 10 sccm for 2 hours. Graphene was grown under the conditions that the working pressure was 5, 10, and 50 mTorr, respectively.

FIG. 8 is a graph showing the Raman spectrum of the graphene layer formed by the above method, the growth area of graphene, and the peak characteristics observed on the Raman spectrum. In FIG. 8, it can be seen that as the working pressure is lower, the growth area of graphene is increased and a graphene layer having excellent crystallinity is formed.

2) Evaluation of growth characteristics of graphene by pretreatment time of Ti layer

Graphene was grown by the same method as in 1) except that the treatment time of the H ₂ gas for removing the surface oxide film of Ti was adjusted to 60, 120, 180 and 240 minutes at 750 ° C, respectively. The working pressure was maintained at 5 mTorr.

9 is a graph showing the Raman spectrum showing the characteristics of graphene formed according to the hydrogen treatment time and the peak characteristics observed on the growth rate and Raman spectrum of graphene. In FIG. 9, it can be seen that the growth area of the graphene increases with the increase of the hydrogen treatment time. When the hydrogen treatment time is short, the signal of the Raman spectrum is weak. However, as the hydrogen treatment time increases, And it was found that the crystallinity was increased because a clear spectrum was obtained.

3) Evaluation of growth characteristics of graphene according to the composition of reaction gas

(1) Evaluation of growth characteristics of graphene with increase of hydrogen inflow in reaction gas

Graphene was grown in the same manner as in 1) except that the composition and flow rate of the reaction gas were adjusted to CH ₄ : H ₂ = 1: 10, 1:20, 1:30 and 1:40 sccm. The working pressure was maintained at 10 mTorr.

10 is a graph showing the Raman spectrum showing the characteristics of graphene formed according to the increase of the hydrogen inflow of the reaction gas and the peak characteristics observed on the growth rate and Raman spectrum of graphene. And also secure the flow rate of the carbon source is CH ₄ at 10, in accordance with the increase of only the hydrogen inflow yes growth speed of the pin was gradually reduced CH _4: H ₂ = 1: the case of 40 sccm Yes sharply reduced growth area of the pin Respectively. The Raman properties of the resulting graphene decreased with increasing hydrogen uptake, and graphene formed under the condition of CH ₄ : H ₂ = 1: 40 sccm showed weak Raman spectral signal.

(2) Evaluation of growth characteristics of graphene with increasing carbon source in reaction gas

Graphene was grown in the same manner as in 1) except that the composition and flow rate of the reaction gas were adjusted to CH ₄ : H ₂ = 1:10, 3:10, 5:10, and 10:10 sccm. The working pressure was maintained at 10 mTorr.

11 is a graph showing the Raman spectrum showing the characteristics of graphene formed according to the increase of the flow rate of methane gas as the carbon source in the reaction gas and the peak characteristics observed on the growth rate and Raman spectrum of graphene. Yes Raman properties of graphene significant decrease in the growth area of the pin, formed as the influx amounts of CH ₄ also increased from 11 was also confirmed that the decrease rapidly.

Claims (8)

(A) depositing a 3 to 20 nm thick Ti layer on the base substrate by sputtering; and
(B) growing graphene on the deposited Ti layer by chemical vapor deposition;
Wherein the graphene layer is formed on the substrate.
The method according to claim 1,
Wherein the base substrate is glass, SiO _2, or a synthetic resin containing oxygen atoms in the structure.
The method according to claim 1,
Wherein the step (B) comprises growing graphene by chemical vapor deposition at a substrate temperature of 150 to 900 占 폚.
The method of claim 3,
Wherein the step (B) comprises growing graphene by a chemical vapor deposition (CVD) process at a substrate temperature of 150 to 400 ° C.
5. The method of claim 4,
Wherein the working pressure during the growth of graphene by chemical vapor deposition in the step (B) is 10 mTorr or less.
The method according to claim 1,
Wherein the Ti layer is treated with hydrogen gas before deposition of the graphene.
The method according to claim 1,
Wherein the reaction gas in the chemical vapor deposition method is a carbon source and is made of a mixture of at least one selected from the group consisting of methane, ethane, propane, acetylene, methanol, ethanol and propanol, and hydrogen gas.
8. A method of manufacturing a semiconductor device comprising a graphene layer formed by the method of any one of claims 1 to 7,
A base substrate;
A 3 to 20 nm Ti layer deposited by sputtering on a base substrate; And
A graphene layer deposited on the Ti layer by chemical vapor deposition;
≪ / RTI > wherein the substrate comprises a substrate.

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