KR102039748B1 - Carbon Based Electronic Device and Its Manufacturing Methods with Locally Reduced Graphene Oxide - Google Patents

Abstract

The present invention provides a graphene-based carbon-based electronic device and a method of manufacturing the same.
Graphene-based electronic device of the present invention is a substrate; A graphene oxide thin film layer formed on the substrate; A gate insulating layer formed on the graphene oxide thin film layer; And a gate electrode formed on the insulating layer. The graphene oxide thin film layer may be one in which graphene oxide is locally reduced by irradiating a laser onto one surface thereof. According to the present invention, the reduction of the graphene oxide has the effect of reducing resistance and improving transparency.

Description

Carbon Based Electronic Device and Locally Reduced Graphene Oxide with Local Reduction of Graphene Oxide

The present invention relates to a carbon-based electronic device using a local reduction of the graphene oxide thin film layer and a method of manufacturing the same. More particularly, the graphene oxide thin film layer is implemented by local reduction of graphene oxide by irradiating a laser to one surface of the graphene oxide thin film layer. It relates to a fin-based carbon-based electronic device and a method of manufacturing the same.

Graphene is a single layer of nanomaterials in which carbon atoms are arranged in a hexagonal form in a two-dimensional plate structure.It is a material that can replace CNTs because of its excellent mechanical strength, chemical and thermal stability, and excellent electrical and electronic properties. Is attracting attention.

Graphene has excellent physical strength, specifically known as 1,100 GPa, which is more than 200 times that of steel. Good physical strength is due to the presence of hard carbon bonds and the absence of bonds in monolayers.

Graphene is also known to have good thermal conductivity of about 500 W / mK at room temperature. Graphene's thermal conductivity is more than 50% higher than CNTs and is about 10 times greater than metals such as copper and aluminum. The excellent thermal conductivity of graphene is because it can easily transfer atomic vibrations, and affects the long average free path of electrons.

Graphene has fast electron mobility and long average free path of electrons. For example, the maximum electron mobility of graphene at room temperature is 2000,000 cm ² / Vs. The electron mobility of graphene is because the scattering degree that inhibits the movement of electrons is very small, and thus has a long average free path. Thus, it has a resistance value of at least 35% as compared with copper, which is known to have a low resistance.

On the other hand, for the industrial application of graphene it is important to synthesize a large area of graphene, the synthesis method is largely divided into a method of mechanically peeled from graphite and chemically synthesized from a carbon source.

The mechanical peeling method from graphite is a method of separating single layer graphene using the adhesive force of the adhesive tape first developed by Geim researchers, the method of chemical peeling by dispersing with a surfactant, etc. in solution, and oxidized graphene oxide. After dispersing the solution phase to make a physical / chemical reduction method (GO / rGO) and the like. As a method of chemically synthesizing from a carbon source, methods such as thermochemical vapor deposition, plasma CVD, chemical synthesis, and pyrolysis of silicon carbide (SiC) are widely used.

High crystalline graphene can be obtained in the case of mechanical peeling, but there is a disadvantage in that the control of the shape is difficult. The chemical exfoliation method and the reduction method of graphite oxide can obtain a large amount of graphene, but there is a problem that crystallinity is inferior due to structural defects generated during the treatment.

In addition, in the case of chemical vapor deposition (CVD), a metal thin plate made of a catalyst metal such as copper or platinum is disposed in an interior space of a graphene synthesis chamber, and hydrocarbons such as methane or ethane are disposed in the graphene synthesis chamber. After the injection into the inner space, by heating the inner space of the graphene synthesis chamber to a high temperature to synthesize the graphene on the surface of the metal sheet (Korea Patent Publication: 2011-0064164), the purity is higher than other graphene Graphene can be made in the desired size, but the amount of graphene produced is very small, the problem of poor productivity is pointed out.

Meanwhile, the epitaxial synthesis method using Pyrolysis of SiC, which is the most representative synthesis method (Korean Patent Publication: 2009-0124330), is a method of pyrolyzing SiC to vaporize Si and forming graphene on the surface of SiC through recombination of C. Since the carbon source is carbon contained in the SiC itself, the experimental method is simple, and it can grow to wafer-level graphene crystals, thereby allowing a large area, and graphene because the graphene / SiC structure is easy to apply to semiconductor processes and easy to apply electronic materials. It is emerging as an alternative to synthesis. However, the thermal decomposition of SiC requires a small graphene size of 30 to 200 nm due to the surface flatness of SiC and the formation of pores, high temperature of 1500 ℃ or higher, ultra low pressure of 1 × 10 ^-8 Pa, and mechanical peeling. There is a problem that the electrical properties are lower than the graphene obtained through the law.

Korea Patent Publication 10-2011-0064164

The present invention was derived to solve the above problems, by irradiating a laser to the graphene oxide thin film layer, induces local reduction of the graphene oxide thin film layer to improve the transparency of the graphene-based carbon-based electronic device without a subsequent patterning process It is an object of the present invention to provide a method for simultaneously producing a single substrate.

In addition, a second object of the present invention is to provide a method for producing a graphene-based carbon-based electronic device capable of local reduction of the graphene oxide thin film layer.

Graphene-based carbon-based electronic device according to the present invention for achieving this object,

Board; A graphene oxide thin film layer formed on the substrate; A gate insulating layer formed on the graphene oxide thin film layer; And a gate electrode formed on the insulating layer. The graphene oxide thin film layer may be locally reduced by irradiating a laser onto one surface of the graphene oxide thin film layer.

In this case, the laser may be an excimer laser.

In the graphene oxide thin film layer, a drain electrode, a source electrode, and a channel layer may be integrally formed on the same surface on the substrate.

A gate insulating layer may be formed on the channel layer, and the channel layer may be formed between the drain electrode and the source electrode.

In addition, the drain electrode and the source electrode may be formed by the local reduction of the graphene oxide thin film layer.

The gate electrode may be formed by depositing a metal on the graphene oxide thin film layer.

Method for manufacturing a graphene-based carbon-based electronic device according to the present invention for achieving the second object of the present invention,

Forming a graphene oxide thin film layer on the substrate; Providing a mask on the graphene oxide thin film layer, and irradiating and patterning a laser; And removing the mask, wherein the graphene oxide thin film layer may be one in which graphene oxide is locally reduced by irradiating a laser.

As one preferred example, the laser may be an excimer laser.

As described above, the graphene-based carbon-based electronic device according to the present invention induces local reduction of the graphene oxide thin film layer by irradiating a laser to one surface of the graphene oxide thin film layer, thereby minimizing the process cost since no patterning process is required. There is an advantage.

In addition, as the graphene oxide thin film layer according to the present invention is locally reduced, the resistance is reduced and the transparency is improved as compared with the conventional art.

In addition, according to the present invention, the integrated circuit can be implemented in a roll-to-roll process to a flexible substrate in a room temperature process has the advantage that it can be mass-produced.

1 is a cross-sectional view of a transistor which is one of graphene-based carbon-based electronic devices according to a preferred embodiment of the present invention;
2 is a schematic diagram of reducing graphene oxide to graphene using an excimer laser according to an embodiment of the present invention;
3 is a flowchart illustrating a method of manufacturing a graphene carbon-based electronic device according to an embodiment of the present invention;
4 is a schematic diagram illustrating a process of a carbon-based device using a roll-to-roll process according to an embodiment of the present invention;
5 is a schematic diagram showing a manufacturing diagram of a graphene-based bottom gate FET (field effect transistor) according to an embodiment of the present invention;
6 is a cross-sectional view illustrating an example of a large-area carbon layer based integrated device according to one preferred embodiment of the present invention;
7 is a graph showing the sheet resistance of Experimental Example 1 according to the present invention;
8 is a graph showing the transparency of Experimental Example 1 according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the following Examples are provided to illustrate the present invention, and the scope of the present invention is not limited thereto.

The present invention provides a graphene-based carbon-based electronic device.

As one preferred example, a substrate; A graphene oxide thin film layer formed on the substrate; A gate insulating layer formed on the graphene oxide thin film layer; And a gate electrode formed on the insulating layer. The graphene oxide thin film layer may be locally reduced by irradiating a laser onto one surface of the graphene oxide thin film layer.

1 is a cross-sectional view showing a graphene-based carbon-based electronic device according to an embodiment of the present invention.

As illustrated in FIG. 1, the graphene-based carbon-based electronic device of the present invention includes a substrate 10, a drain electrode 21, a source electrode 22, and the drain electrode 21 formed on the substrate 10, respectively. ) And a channel layer 30 formed between the source electrode 22 and the source electrode 22, a gate insulating layer 40 formed on the channel layer 30, and a gate electrode 50 formed on the gate insulating layer 40. Can be.

As such, the graphene-based carbon-based electronic device including the graphene oxide thin film layer 20 according to the present invention may induce local reduction by irradiating a laser to one surface of the graphene oxide thin film layer 20, thereby eliminating the subsequent patterning process. Can be.

In addition, the graphene-based carbon-based electronic device according to the present invention has a low sheet resistance and excellent transparency characteristics, and because the capacitor, the source / drain electrode and the like can be simultaneously manufactured on a single substrate, the process efficiency is excellent.

For reference, in the present invention, an electronic device should be understood as a concept of referring to various devices including a memory device, a detection device, a diode, a transistor, a light emitting device, an integrated circuit, or a part of these devices.

The substrate 10 may be made of metal, glass, resin, or the like. As the material of the substrate 10, silicon, silicon carbide, gallium arsenide, spinel, indium phosphide, gallium phosphide, aluminum phosphide, gallium nitride, and indium nitride , Aluminum nitride, zinc oxide, magnesium oxide, aluminum oxide, titanium oxide, sapphire, quartz, pyrex may be used, but is not limited to these materials.

Forming a graphene oxide thin film layer 20 on the substrate 10, the graphene oxide thin film layer 20 may be formed by spraying, coating and drying a graphene oxide solution on the substrate 10 and then heat treatment have. The graphene oxide solution may be preferably formed by oxidizing the graphite powder by adding an acid such as sulfuric acid, followed by heat treatment, and then performing UV or O ₂ plasma treatment. no.

The coating may be any one of spin coating, electrospray coating, screen coating, offset printing, inkjet printing, spray method, pad printing, knife coating, key coating, gravure coating, brushing, ultrasonic fine spray coating, and spray-mist spray coating. It may be selected, but is not limited thereto.

The solvent of the graphene oxide solution is water, acetone, methyl ethyl ketone, methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, ethylene glycol, ethylene glycol, polyethylene glycol, tetrahydrofuran, dimethylformamide , Dimethylacetamide, N-methyl-2-pyrrolidone, hexane, cyclohexanone, toluene, chloroform, distilled water, dichlorobenzene, dimethylbenzene, trimethylbenzene, pyridine, methylnaphthalene, nitromethane, acrylonitrile It can be one.

In addition, a non-polar solvent may be added for uniform dispersion of the graphene oxide solution of the present invention, for example, acetone, methyl ethyl ketone, methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, ethylene glycol Chol, ethylene glycol, polyethylene glycol, tetrahydrofuran, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, hexane, cyclohexanone, toluene, chloroform, distilled water, dichlorobenzene, Preference is given to dimethylbenzine, trimethylbenzene, pyridine, methylnaphthalene, nitromethane, acrylonitrile, octadecylamine, aniline, dimethylsulfoxide, methylene chloride, diethylene glycol methyl ethyl ether, ethyl acetate. Such a nonpolar solvent not only makes the dispersion of graphene oxide uniform, but also has an effect of reducing surface roughness.

In order to locally reduce the graphene oxide thin film layer 20 of the present invention, it may be irradiated using an excimer laser.

2 is a schematic diagram of reducing graphene oxide to graphene using an excimer laser according to an embodiment of the present invention.

Specifically, referring to Figure 2, by irradiating the graphene oxide in the form of a pulse using an excimer laser, only the region irradiated with the laser is reduced to graphene while removing the -O-, -OH or -COOH functional group. As described above, since only the region irradiated with the excimer laser is locally reduced to graphene, the graphene local reduction and patterning may be simultaneously performed.

In this case, the excimer laser may be irradiated using the S / D mask or the channel mask, and the subsequent patterning process may not be performed by directly patterning the S / D mask or the channel mask.

In some cases, when irradiating an excimer laser, it can be focused by using an objective lens or the like, can be irradiated at room temperature, and can be irradiated while heating the substrate at a temperature of 200 ° C. or less in consideration of device characteristics.

In one preferred example, the pulse width of the excimer laser may be greater than 10 and less than 50 nS. If the pulse width is greater than 50 nS, the thermal energy may be excessively supplied and the surface may be damaged. Since this cannot be done, it is not desirable.

In another preferred example, the irradiated energy of the excimer laser may be between 100 and 1000 mJ or less. When the energy of the laser is less than 100 mJ, the reaction temperature is lowered to prevent sufficient reduction. On the contrary, when the energy is exceeded 1000 mJ, the surface of the graphene oxide thin film layer may be damaged, and thus the desired effect of the present invention cannot be expected. .

The graphene oxide thin film layer 20 formed on the substrate 10 has a structure in which the drain electrode 21, the source electrode 22, and the channel layer 30 are integrally formed on the same surface on the substrate 10 (FIG. 1). The drain electrode 21 and the source electrode 22 may be formed of locally reduced graphene by irradiating the excimer laser.

The channel layer 30 may be formed by partially reducing the graphene oxide thin film layer 20 between the drain electrode 21 and the source electrode 22, and the gate electrode 50 may be formed. It may be formed by depositing a metal 13 on the fin oxide thin film layer 20.

In addition, the insulating layer 40 is a region not irradiated with laser, and the lower portion of the metal 13 is oxidized or subsequently formed by chemical bonding while depositing the metal 13 on the graphene oxide thin film layer 20. It may be oxidized and formed by a thermal process.

In a preferred embodiment of the present invention, the graphene-based carbon-based electronic device may be applied to integrated devices such as thin film transistors, gas sensors, memories, capacitors, and the like.

In addition, the present invention provides a method for manufacturing a graphene-based carbon-based electronic device.

In one preferred example, forming a graphene oxide thin film layer on a substrate; Providing a mask on the graphene oxide thin film layer, and irradiating and patterning a laser; And removing the mask, wherein the graphene oxide thin film layer may be one in which graphene oxide is locally reduced by irradiating a laser. Preferably, it can be irradiated using an excimer laser.

3 is a flowchart illustrating a method of manufacturing a graphene-based carbon-based electronic device according to an embodiment of the present invention.

As shown in FIG. 3, the method for manufacturing a graphene-based carbon-based electronic device of the present invention includes forming a graphene oxide thin film layer on a substrate (S310); Providing a mask on the graphene oxide thin film layer, and patterning by irradiating a laser (S320); And removing the mask (S330); to form a graphene-based carbon-based electronic device S340.

The series of processes may be applied to a roll-to-roll type process for implementing graphene-based carbon-based integrated devices.

Figure 4 is a schematic diagram illustrating a process of a carbon-based device using a roll-to-roll process according to an embodiment of the present invention.

Referring to FIG. 4, a supply unit 410 continuously supplying a substrate; A graphene synthesis unit 420 for spraying and coating a graphene oxide solution on the surface of the supplied substrate; A laser irradiation part 430 irradiating a laser onto one surface of the graphene oxide thin film passing through the graphene synthesis part; It may have a structure including a recovery unit 440 for recovering the irradiated graphene oxide thin film.

The graphene synthesis unit 420 may spray and coat a graphene oxide solution on a substrate to generate a graphene oxide thin film layer, and then dry and heat-treat the surface. In addition, the laser irradiation unit 430 may include a step of directly patterning using an S / D mask, a channel mask, and the like.

Furthermore, the FET of the integrated device of the present invention can be implemented by using a S / D mask and a channel mask and continuously irradiating a laser. FIG. 5 is a conceptual diagram illustrating the fabrication of an organic FET according to an embodiment of the present invention. It is a schematic diagram.

Referring to FIG. 5, a graphene oxide thin film layer 520 is formed on a SiO ₂ / Si substrate 510, and an excimer laser 540 using an S / D mask 531 on the graphene oxide thin film layer 520. ). When the number of laser pulses is irradiated 10 times or more, a region of high reduction graphene oxide (HrGO) 551 is formed, and the S / D mask is removed. Subsequently, the number of laser pulses may be irradiated less than five times using the channel mask 532 to form a region of reduced reduction graphene oxide (LrGO) 552. That is, the integrated device FET may be implemented by continuously irradiating a laser using the S / D mask 531 and the channel mask 532.

As described above, the graphene-based carbon-based electronic device according to the present invention, by using a roll-to-roll method on the substrate at room temperature, a graphene-based carbon-based electronic device directly on a single substrate, for example, gate electrode, source / drain electrode And the like can be implemented simultaneously. This is shown in FIG. 6.

6 is a cross-sectional view illustrating an example of a large area carbon-based integrated device.

Referring to FIG. 6, when an excimer laser is irradiated using an S / D mask, a channel mask, or the like on a graphene oxide thin film layer, the conductive regions 610, 640, 650, and 670 may be formed according to the number of laser pulse irradiation (ρ < 1 Ω / cm) and the semiconducting regions 620 and 660 (1 <ρ <10 ³ cm / cm) can be simultaneously implemented. In addition, as described above, the insulating region 630 (ρ> 10 ³ μs / cm) may also be implemented in the region to which the laser is not irradiated. The conductive regions 610, 640, 650, and 670 may be used as electrodes 640, 650, and 670 of integrated devices, and the semiconductor regions may be insulated from active layers and capacitors in channel memories of field effect transistors (FETs). The layer 660 may be utilized.

In addition, when implementing a graphene-based carbon-based integrated device according to the present invention, the advantage of not having to perform an O ₂ plasma etching process for the patterning and removal of the photo-resistor (PR) and the removal of the undesired graphene oxide thin film layer have.

{Example}

Example 1

A graphene oxide solution was prepared and 5 mg / ml was sprayed and coated on a transparent substrate using a spin coating method to form a 30 nm graphene oxide thin film layer.

The desired graphene oxide thin film layer was irradiated with a laser to reduce only desired regions to graphene. At this time, irradiation was performed with a pulse width of 20 nS, an energy of 300 mJ per pulse, a beam width of 5 x 15 mm ² , a wavelength of 248 nm, and the number of laser pulses.

Example 2

In the said Example 1, it irradiated similarly to Example 1 except having irradiated with the laser pulse number 3.

Example 3

In Example 1, irradiation was performed in the same manner as in Example 1 except that the number of laser pulses was set at five.

Example 4

In Example 1, irradiation was performed in the same manner as in Example 1 except that the number of laser pulses was 10.

Comparative Example 1

In Example 1, the same method as in Example 1 was used except that the graphene oxide thin film layer was not irradiated with laser (pritine GO).

Experimental Example 1: Measurement of sheet resistance (Rs) and transparency due to laser irradiation]

According to Examples 1 to 4 and Comparative Example 1, sheet resistance and transparency according to the number of laser pulses were measured, and the results are shown in FIGS. 7 and 8.

7 is a graph showing the sheet resistance of Experimental Example 1, Figure 8 is a graph showing the transparency of Experimental Example 1.

Referring to FIG. 7, it was confirmed that the sheet resistance decreased as the number of laser pulses increased (Example 1 to Example 4). In addition, the sheet resistance value of Example 1 was slightly higher than the sheet resistance value of Example 4, but Example 1 was also reduced (Lower reduction), Example 4 was confirmed to be a complete reduction (Higher reduction).

In addition, the sheet resistance is expressed as a specific resistance per unit thickness of the thin film, so that the resistivity of Comparative Example 1 is 3.0 × 10 ³ Ω / cm, the resistivity of Example 4 is 9.09 × 10 ⁻¹ Ω / cm, and the sheet resistance of Example 4 is As compared with the sheet resistance value of Comparative Example 1, it was confirmed that the decrease of about ~ 10 ⁵ . This can be said to improve the sheet resistance characteristics.

On the other hand, there is a correlation between the sheet resistance and transparency, referring to Figure 8, it can be seen that the transparency is also improved. Specifically, it can be seen that the transparency of Comparative Example 1 is 73, the transparency of Example 2 is 80, and the transparency of Example 4 is increased to 92 at a wavelength of 550 nm.

That is, the locally reduced graphene oxide thin film layer prepared according to the present invention may be applied to a flexible display, an integrated circuit, etc. as the sheet resistance decreases and the transparency increases as the number of laser pulses increases.

The embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical spirit of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention, as will be apparent to those skilled in the art.

10: substrate
12: mask
13: metal
20: graphene oxide thin film layer
21: drain electrode
22: source electrode
30: channel layer
40: insulation layer
50: gate electrode

Claims (9)

Board;
A graphene oxide thin film layer formed on the substrate;
A gate insulating layer formed on the graphene oxide thin film layer by oxidation by a subsequent thermal process; And
Including; a gate electrode formed on the insulating layer,
The graphene oxide thin film layer is a graphene oxide is locally reduced by applying a high temperature by irradiating an excimer laser on one surface;
The graphene oxide thin film layer is a graphene carbon-based electronic device, characterized in that the drain electrode, the source electrode and the channel layer is integrally formed on the same surface on the substrate. The method of claim 1,
Graphene-based carbon-based electronic device, characterized in that the pulse width of the excimer laser is more than 10nS 50nS. delete The method of claim 1,
The graphene-based carbon-based electronic device, characterized in that the gate insulating layer formed on the channel layer by the subsequent thermal process is formed by itself. The method of claim 1,
The channel layer is a graphene-based carbon-based electronic device, characterized in that formed between the drain electrode and the source electrode. The method of claim 1,
The drain electrode and the source electrode is a graphene carbon-based electronic device, characterized in that the graphene oxide thin film layer is formed by local reduction. The method of claim 1,
The gate electrode is a graphene carbon-based electronic device, characterized in that formed by depositing a metal on the graphene oxide thin film layer. delete delete

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