KR102036971B1 - Oxide thin film transistor and method of manufacturing the same - Google Patents

Abstract

The present invention discloses an oxide thin film transistor and a method of manufacturing the same. An oxide thin film transistor according to an embodiment of the present invention includes a gate electrode formed on a substrate; A gate insulating layer formed on the gate electrode; An oxide semiconductor thin film on the gate insulating layer; And a source electrode and a drain electrode spaced apart from each other on the oxide semiconductor thin film, and coating the activated sodium hypochlorite solution through a light source on the oxide semiconductor thin film to activate the formed oxide semiconductor thin film through heat treatment. Characterized in that.

Description

OXIDE THIN FILM TRANSISTOR AND METHOD OF MANUFACTURING THE SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide thin film transistor and a method of manufacturing the same, and more particularly, to an oxide thin film transistor for a flexible display device, which has improved electrical characteristics by coating an activated sodium hypochlorite (NaClO) solution through a light source on an oxide semiconductor thin film. And to a method for producing the same.

There are a silicon based thin film transistor (TFT) and an oxide thin film transistor using amorphous silicon (a-Si) or polysilicon (poly-Si) as a switching device or driving device used as a backplane of a display. .

Amorphous silicon (a-Si) thin film transistors of silicon (Si) based thin film transistors are easy to manufacture but have low electron mobility. On the other hand, poly-Si thin-film transistors have higher electron mobility than amorphous silicon (a-Si) thin-film transistors, which are applicable to high-resolution displays of large areas and have high stability, but have complicated manufacturing processes and high manufacturing costs. There is a problem in that a compensation circuit is required due to non-uniformity of device characteristics in the panel.

Oxide thin film transistors have been developed to solve the drawbacks of such silicon-based thin film transistors. Oxide thin film transistors have high mobility and low off-current compared to conventional amorphous silicon (a-Si) thin film transistors, and thus, they are attracting much attention in terms of the possibility of next-generation display driving devices.

As a method for forming an oxide semiconductor used as a channel layer region of an oxide thin film transistor, there is a method of physically or chemically depositing an oxide semiconductor on a substrate using vacuum equipment. However, this method requires a high production cost.

As a method for overcoming these disadvantages, there is a method of forming an oxide semiconductor using a solution process. However, despite the advantage of lowering the production cost, in order to activate the device of the oxide thin film transistor manufactured by the solution process, a high temperature heat treatment of 300 ° C. or more is required, which is accompanied by deterioration of characteristics such as denaturation and discoloration at high temperatures. Difficulties exist in application to substrates of flexible displays.

Therefore, it is possible to activate the oxide thin film transistor at a lower temperature than the existing 300 ° C, but it is necessary to research and develop a method of manufacturing an oxide semiconductor based on a solution process that can improve reliability.

Korean Laid-Open Patent Publication No. 10-2008-0105368, "Carbon Nanotube with Improved Conductivity, Method for Manufacturing the Electrode and the Carbon Nanotube Containing Electrode" U.S. Patent No. 3,176,153, "MESA-TYPE FIELD-EFFECT TRANSISTORS AND ELECTRICAL SYSTEM THEREFOR"

Qing Zhang, "High-Sensitivity, Highly Transparent, Gel-Gated MoS2 Phototransistor on Biodegradable Nanopaper" (2016.6.21)

Embodiments of the present invention are to provide an oxide thin film transistor capable of a low temperature process based on the solution process by manufacturing an oxide semiconductor thin film using a sodium hypochlorite solution activated through a light source and a method of manufacturing the same.

Embodiments of the present invention are to provide an oxide thin film transistor and a method of manufacturing the oxide semiconductor thin film by using the sodium hypochlorite solution activated through a light source to improve the electrical characteristics of the device.

Embodiments of the present invention are to provide an oxide thin film transistor and a method of manufacturing the same by improving the electrical characteristics of the device by activating the oxide semiconductor thin film through annealing (annealing).

An oxide thin film transistor according to an embodiment of the present invention includes a gate electrode formed on a substrate; A gate insulating layer formed on the gate electrode; An oxide semiconductor thin film on the gate insulating layer; And a source electrode and a drain electrode spaced apart from each other on the oxide semiconductor thin film, and coating the activated sodium hypochlorite solution through a light source on the oxide semiconductor thin film to activate the formed oxide semiconductor thin film through heat treatment. Characterized in that.

The heat treatment may be performed at a temperature in the range of 25 ℃ to 300 ℃.

The heat treatment may be performed for 5 to 60 minutes.

Irradiation of the light source may be performed for 5 to 60 minutes.

The amount of sodium hypochlorite solution may be 0.1mL to 5mL.

The oxide semiconductor thin film is amorphous indium gallium-zinc oxide (a-IGZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium tin oxide (ITO), zinc tin oxide (ZTO) , Silicon indium zinc oxide (SIZO), gallium zinc oxide (GZO), hafnium indium zinc oxide (HIZO), zinc indium tin oxide (ZITO) and aluminum zinc tin oxide (AZTO) may include an oxide.

An oxide thin film transistor according to an exemplary embodiment of the present invention includes a source electrode and a drain electrode spaced apart from each other on a substrate; An oxide semiconductor thin film formed on the source electrode and the drain electrode; A gate insulating layer formed on the oxide semiconductor thin film; And a gate electrode formed on the gate insulating layer, and coating the activated sodium hypochlorite solution through the light source on the oxide semiconductor thin film to activate the formed oxide semiconductor thin film through heat treatment.

Method of manufacturing an oxide thin film transistor according to an embodiment of the present invention comprises the steps of forming a gate electrode on the substrate; Forming a gate insulating layer formed on the gate electrode; Forming an oxide semiconductor thin film on the gate insulating layer; Coating the activated sodium hypochlorite solution on the oxide semiconductor thin film through a light source; Activating the formed oxide semiconductor thin film through heat treatment; And forming a source electrode and a drain electrode spaced apart from each other on the oxide semiconductor thin film. It includes.

According to an embodiment of the present invention, an oxide thin film transistor capable of a low temperature process based on a solution process may be provided by manufacturing an oxide thin film using a sodium hypochlorite solution activated through a light source.

In addition, according to an embodiment of the present invention, by manufacturing an oxide thin film using a sodium hypochlorite solution activated through a light source, it is possible to provide an oxide thin film transistor having improved electrical characteristics of a device such as a threshold voltage.

In addition, according to an embodiment of the present invention, it is possible to provide an oxide thin film transistor and a method of manufacturing the same by improving the electrical characteristics of the device by activating the oxide semiconductor thin film through heat treatment.

1A to 1H illustrate a method of manufacturing an oxide thin film transistor according to an exemplary embodiment of the present invention.
2 is a cross-sectional view of an oxide thin film transistor according to another exemplary embodiment of the present invention.
FIG. 3 is a graph illustrating electrical (voltage-current) characteristics according to heat treatment temperatures of an oxide semiconductor thin film not coated with sodium hypochlorite solution of an oxide thin film transistor according to an exemplary embodiment of the present invention.
4 and 5 illustrate an oxide thin film transistor including an oxide semiconductor thin film coated with sodium hypochlorite solution in an oxide thin film transistor according to an embodiment of the present invention when heat treated at a temperature of 150 ° C. and 100 ° C. for 1 hour, respectively. It is a graph showing the electrical (voltage-current) characteristics.
FIG. 6 illustrates a case in which an oxide semiconductor thin film not coated with sodium hypochlorite solution is heat-treated at 300 ° C. and an oxide semiconductor thin film coated with sodium hypochlorite solution in an oxide thin film transistor according to an embodiment of the present invention. The table shows the electrical properties when heat treated at.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or limited to the embodiments.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

As used herein, “an embodiment”, “an example”, “side”, “an example”, etc., should be construed that any aspect or design described is better or advantageous than other aspects or designs. It is not.

In addition, the term 'or' refers to an inclusive or 'inclusive or' rather than an exclusive or 'exclusive or'. In other words, unless stated otherwise or unclear from the context, the expression 'x uses a or b' means any one of natural inclusive permutations.

Also, the singular forms “a” or “an”, as used in this specification and in the claims, generally refer to “one or more” unless the context clearly dictates otherwise or in reference to a singular form. Should be interpreted as

In addition, when a part such as a film, layer, area, configuration request, etc. is said to be "on" or "on" another part, the other film, layer, area, component in the middle, as well as when it is directly above another part. It also includes the case where it is interposed.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In addition, like reference numerals refer to like elements while describing the drawings.

1A to 1H illustrate a method of manufacturing an oxide thin film transistor according to an exemplary embodiment of the present invention.

An oxide thin film transistor 100 according to an embodiment of the present invention may include a substrate 110, a first gate electrode 120, a gate insulating layer 130, an oxide semiconductor thin film 140, and source / drain electrodes 160 and 170. Include.

1A and 1B, in the method of manufacturing the oxide thin film transistor 100 according to the exemplary embodiment of the present disclosure, a substrate 110 is prepared, and a gate electrode 120 is formed on the prepared substrate 110.

As shown in FIG. 1A, the substrate 110 is a substrate for supporting various components of the oxide thin film transistor, and the material of the substrate 110 is not particularly limited.

For example, the substrate 110 may be made of any one material selected from the group consisting of glass, polyimide polymer, polyester polymer, silicon polymer, acrylic polymer, polyolefin polymer, or copolymers thereof.

In some embodiments, the substrate 110 may include polyester, polyvinyl, polycarbonate, polyethylene, polyacetate, polyimide, and polyether sulfone. (Polyethersulphone (PES), Polyacrylate (PAR), Polyethylenenaphthelate (PEN) and Polyethyleneterephehalate (PET) composed of a transparent flexible material composed of any one material selected from the group consisting of Can be.

As illustrated in FIG. 1B, the gate electrode 120 may be formed on the substrate 110.

For example, the gate electrode 120 may be formed by vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, or organometallic chemical deposition. Organic Chemical Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition, Molecular Beam Epitaxy, Hydride Vapor Phase Epitaxy, Sputtering, Spin Coating It may be formed using at least one method of dip coating and zone casting.

The gate electrode 120 may be any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be made of a combination of, but is not limited thereto, and may be made of various materials.

In some embodiments, the gate electrode 120 may use p ⁺ -Si material as the gate electrode 120.

Referring to FIG. 1C, in the method of manufacturing the oxide thin film transistor 100 according to the exemplary embodiment, a gate insulator 130 is formed on the gate electrode 120.

The gate insulating layer 130 is formed on the gate electrode 120 to insulate the gate electrode 120 from the oxide semiconductor thin film 140 (see FIG. 1D).

The gate insulating layer 130 may include vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, and organic metal chemical vapor deposition. Deposition, Plasma-Enhanced Chemical Vapor Deposition, Molecular Beam Epitaxy, Hydride Vapor Phase Epitaxy, Sputtering, Spin Coating, Dip Coating It may be formed using at least one method of (dip coating) and zone casting (zone casting).

The gate insulating layer 130 may be, for example, an inorganic material such as silicon oxide (SiO _x ), silicon nitride (SiN _x ), titanium oxide (TiO _x ), hafnium oxide (HfO _x ), or polyvinyl alcohol (PVA), Organic materials such as polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMMA), and the like.

However, the material and the method of forming the gate insulating layer 130 are not limited thereto, and other known materials and other methods may be used.

Referring to FIG. 1D, in the method of manufacturing the oxide thin film transistor 100 according to the exemplary embodiment, the oxide semiconductor thin film 140 is formed on the gate insulating layer 130. In order to form the oxide semiconductor thin film 140, first, an oxide is deposited on the gate insulating layer 130.

The oxide may be deposited by any one of a sputtering process, a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, and a solution process.

In addition, the oxide may be formed using any one of spin coating, spray coating, inkjet coating, slit coating, or deep coating. 130), but the method is a coating method used in the art, and the method is not particularly limited.

The oxide may be a multicomponent material such as indium gallium zinc oxide (IGZO; InGaZnO), a bicomponent material such as indium zinc oxide (IZO; InZnO), or a single component oxide semiconductor material such as zinc oxide (ZnO).

Specifically, the oxide may be amorphous indium gallium zinc oxide (a-IGZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium tin oxide (ITO), zinc tin oxide (ZTO). ), Silicon indium zinc oxide (SIZO), gallium zinc oxide (GZO), hafnium indium zinc oxide (HIZO), zinc indium tin oxide (ZITO) and aluminum zinc tin oxide (AZTO). The thin film 140 made of such an oxide is amorphous, but has high mobility, and has a large band gap, thereby being applicable to a transparent display.

Referring to FIG. 1E, the method of manufacturing the oxide thin film transistor 100 according to the exemplary embodiment of the present invention coats the activated sodium hypochlorite solution on the oxide semiconductor thin film 140 through a light source.

The sodium hypochlorite generates reactive oxygen species by a light source, and the active oxygen may increase the oxygen concentration capable of reacting with the oxide semiconductor thin film at low temperature.

Therefore, by coating the sodium hypochlorite on the oxide semiconductor thin film 140, it is possible to increase the metal-oxygen bond even at a relatively low temperature than otherwise.

The amount of the sodium hypochlorite solution coated on the oxide semiconductor thin film 140 may be 0.5mL to 5mL, and the method of coating the sodium hypochlorite solution on the oxide semiconductor thin film 140 may be used in the art. Can be. Specifically, spin coating, spray coating, inkjet coating, slit coating or deep coating may be used. It is not limited.

Referring to FIG. 1F, in the method of manufacturing the oxide thin film transistor 100 according to the exemplary embodiment of the present invention, the sodium hypochlorite solution coated on the oxide semiconductor thin film 140 is activated through irradiation of a light source, and gate insulation The oxide semiconductor thin film 140 formed on the layer 130 may be activated through heat treatment.

When the oxide semiconductor thin film 140 is heat-treated, the concentration of oxygen vacancies in the oxide semiconductor thin film is increased and the electron concentration thereof is increased, thereby improving electrical characteristics of the oxide semiconductor thin film.

The light source used to activate the sodium hypochlorite solution has a wavelength in the visible light range, specifically, may be 400nm to 700nm.

Irradiation of the light source may be performed for 5 to 60 minutes, specifically, may be performed in a time range shorter or the same as the heat treatment time.

The heat treatment may be carried out at a temperature in the range of 25 ℃ to 300 ℃, preferably at a temperature of 100 ℃ or more.

The heat treatment may be performed for 5 to 60 minutes.

Referring to FIG. 1G, the method of manufacturing the oxide thin film transistor 100 according to the exemplary embodiment of the present invention performs a cleaning process of the activated oxide semiconductor thin film 140.

Referring to FIG. 1H, the source electrode 160 and the drain electrode 170 may be formed to be spaced apart from each other on the oxide semiconductor thin film 140 according to an embodiment of the present invention.

 The source electrode 160 and the drain electrode 170 are, for example, aluminum (Al), aluminum alloy (Al alloy), tungsten (W), copper (Cu), nickel (Ni), chromium (Cr), molybdenum ( Low resistance conductive materials such as Mo), titanium (Ti), platinum (Pt), or tantalum (Ta) may be used.

In addition, the source electrode 160 and the drain electrode 170 may use a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or indium tin zinc oxide (ITZO).

In some embodiments, the source electrode 160 and the drain electrode 170 may be formed in a multilayer structure in which two or more conductive materials are stacked.

2 is a cross-sectional view of an oxide thin film transistor according to another exemplary embodiment of the present invention.

2, an oxide thin film transistor 200 according to an exemplary embodiment of the present invention may include a substrate 210, a source electrode 220, a drain electrode 230, and a source electrode 220 formed on the substrate 210. And an oxide semiconductor thin film 240 formed on the drain electrode 230, a gate insulating layer 250 formed on the oxide semiconductor thin film 240, and a gate electrode 260 formed on the gate insulating layer 250.

The substrate 210 is a substrate for supporting various components of the oxide thin film transistor, and the material of the substrate 210 is not particularly limited.

For example, it may be made of any one material selected from the group consisting of glass, polyimide polymer, polyester polymer, silicone polymer, acrylic polymer, polyolefin polymer, or copolymers thereof.

In some embodiments, the substrate 210 may include polyester, polyvinyl, polycarbonate, polyethylene, polyacetate, polyimide, and polyether sulfone. (Polyethersulphone (PES), Polyacrylate (PAR), Polyethylenenaphthelate (PEN) and Polyethyleneterephehalate (PET) composed of a transparent flexible material composed of any one material selected from the group consisting of Can be.

The source electrode 220 and the drain electrode 230 are formed on the substrate 210.

For example, the source electrode 220 and the drain electrode 230 may include aluminum (Al), aluminum alloy (Al alloy), tungsten (W), copper (Cu), nickel (Ni), chromium (Cr), and molybdenum ( Low resistance conductive materials such as Mo), titanium (Ti), platinum (Pt), or tantalum (Ta) may be used.

In addition, the source electrode 220 and the drain electrode 230 may use a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or indium tin zinc oxide (ITZO).

In some embodiments, the source electrode 220 and the drain electrode 230 may be formed in a multilayer structure in which two or more conductive materials are stacked.

The oxide semiconductor thin film 240 is formed on the source electrode 220 and the drain electrode 230. Specifically, in order to form the oxide semiconductor thin film 240, first, an oxide is deposited on the source electrode 220 and the drain electrode 230.

The oxide may be a multicomponent material such as indium gallium zinc oxide (IGZO; InGaZnO), a bicomponent material such as indium zinc oxide (IZO; InZnO), or a single component oxide semiconductor material such as zinc oxide (ZnO).

Specifically, the oxide may be amorphous indium gallium zinc oxide (a-IGZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium tin oxide (ITO), zinc tin oxide (ZTO). ), Silicon indium zinc oxide (SIZO), gallium zinc oxide (GZO), hafnium indium zinc oxide (HIZO), zinc indium tin oxide (ZITO) and aluminum zinc tin oxide (AZTO). The thin film 250 made of such an oxide is amorphous, but has high mobility, and has a large band gap, thereby being applicable to a transparent display.

The coating method of the oxide is a coating method used in the art, but the method is not particularly limited, but spin coating, spray coating, inkjet coating, slit coating ) Or a deep coating may be used, and preferably a spin coating method may be used.

The spin coating method is a method of coating a substrate by centrifugal force applied to the solution by dropping a predetermined amount of the solution on the substrate and rotating the substrate at a high speed.

The sodium hypochlorite solution is coated on the oxide semiconductor thin film 240 coated on the source electrode 220 and the drain electrode 230.

The amount of the sodium hypochlorite solution coated on the oxide semiconductor thin film 240 may be 0.1mL to 5mL, and the method of coating the sodium hypochlorite solution on the oxide semiconductor thin film 240 may be used in the art. Can be.

Specifically, spin coating, spray coating, inkjet coating, slit coating or deep coating may be used. It is not limited.

The sodium hypochlorite solution coated on the oxide semiconductor thin film 240 is activated through irradiation of a light source, and the oxide semiconductor thin film 240 formed on the source electrode 220 and the drain electrode 230 is activated through heat treatment. Can be.

The light source used to activate the sodium hypochlorite solution has a wavelength in the visible light range, specifically, may be 400nm to 700nm. Irradiation of the light source may be performed for 5 to 60 minutes, specifically, may be performed in a time range shorter or the same as the heat treatment time.

The heat treatment may be carried out at a temperature in the range of 25 ℃ to 300 ℃, preferably at a temperature of 100 ℃ or more.

The heat treatment may be performed for 5 to 60 minutes.

The oxide semiconductor thin film 240 activated through heat treatment may remove NaCl, Na ⁺ , Cl ⁻ , and the like remaining on the oxide semiconductor thin film 240 using DI water (Deionized water).

The gate insulating layer 250 is formed on the oxide semiconductor thin film 240.

The gate insulating layer 250 may be formed by vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, and organic metal chemical vapor deposition. Deposition, Plasma-Enhanced Chemical Vapor Deposition, Molecular Beam Epitaxy, Hydride Vapor Phase Epitaxy, Sputtering, Spin Coating, Dip Coating It can be formed using at least one method of (dip coating) and zone casting (zone casting).

The gate insulating layer 250 may be formed of an inorganic material such as silicon oxide (SiO _x ), silicon nitride (SiN _x ), titanium oxide (TiO _x ), hafnium oxide (HfO _x ), or polyvinyl alcohol (PVA), polyvinylpyrroly Organic material such as pig (PVP), polymethylmethacrylate (PMMA).

However, the material and the process method of forming the gate insulating layer 250 are not limited thereto, and other known materials and other methods may be used.

The gate electrode 260 is formed on the gate insulating layer 250.

The gate electrode 260 may be formed by vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, or organic metal chemical vapor deposition. ), Plasma-Enhanced Chemical Vapor Deposition, Molecular Beam Epitaxy, Hydride Vapor Phase Epitaxy, Sputtering, Spin Coating, Dip Coating It may be formed using at least one of dip coating and zone casting.

The gate electrode 260 may be any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be made of a combination of, but is not limited thereto, and may be made of various materials.

In some embodiments, the gate electrode 260 may use p ⁺ -Si material as the gate electrode 260.

Hereinafter, the characteristics of the oxide thin film transistor according to the exemplary embodiment of the present invention will be described with reference to FIGS. 3 to 6.

(Example)

(Preparation of substrate and gate electrode)

A gate electrode was formed by depositing and patterning a metal material such as aluminum (Al) on a boron-doped P-type silicon (heavily boron doped Si) substrate.

(gate Insulation layer  Ready)

A silicon oxide (SiO ₂ ) layer was formed to a thickness of 120 nm through dry oxidation on the substrate on which the gate electrode was formed. Then, the SiO ₂ / p ⁺ -si substrate formed in the above steps was washed at a temperature of 35 ℃ for 10 minutes using an ultrasonic cleaner in the order of acetone, methanol.

As described above, in an argon (Ar) gas atmosphere by sputtering using amorphous indium-galliumzinc oxide (IGZO) having an In: Ga: Zn ratio of 1: 1: 1 on the substrate on which the gate electrode and the gate insulating layer are formed. A 40 nm thick oxide was deposited to form an oxide semiconductor thin film.

Thereafter, spin coating was performed for 30 seconds at a speed of 3000 rpm to coat the sodium hypochlorite solution on the oxide semiconductor thin film.

The substrate coated with sodium hypochlorite solution was heat-treated at a temperature of 150 ° C. for 1 hour, and then the remaining NaCl, Na ⁺ , and Cl ⁻ were removed by cleaning the structure including the oxide semiconductor thin film using DI water (Deionized water). It was.

After the activation of the oxide semiconductor thin film, the oxide thin film transistor was completed by depositing a source electrode and a drain electrode having a width and a length of 1000 μm and 150 μm, respectively, by using a shadow mask and thermal evaporation.

FIG. 3 is a graph illustrating electrical (voltage-current) characteristics according to heat treatment temperatures of an oxide semiconductor thin film not coated with sodium hypochlorite solution of an oxide thin film transistor according to an exemplary embodiment of the present invention.

Referring to FIG. 3, when the oxide semiconductor thin film of the oxide thin film transistor is heat treated at temperatures of 100 ° C., 150 ° C., 200 ° C., 250 ° C., and 300 ° C., respectively, at least the heat treatment temperature should be 300 ° C. or more. It can be confirmed that the oxide semiconductor thin film is activated.

4 and 5 illustrate an oxide thin film transistor including an oxide semiconductor thin film coated with sodium hypochlorite solution in an oxide thin film transistor according to an embodiment of the present invention when heat treated at a temperature of 150 ° C. and 100 ° C. for 1 hour, respectively. It is a graph showing the electrical (voltage-current) characteristics.

4 and 5, although the oxide thin film transistor including the oxide semiconductor thin film coated with sodium hypochlorite solution was heat-treated at a temperature of 150 ° C. and 100 ° C. lower than 300 ° C., the activation of the oxide thin film transistor was not performed. It can be seen that the electrical properties are improved compared to the oxide thin film transistor including the oxide semiconductor thin film not coated with sodium hypochlorite solution.

FIG. 6 illustrates a case in which an oxide semiconductor thin film not coated with sodium hypochlorite solution is heat-treated at 300 ° C. and an oxide semiconductor thin film coated with sodium hypochlorite solution in an oxide thin film transistor according to an embodiment of the present invention. This table shows electrical characteristics (saturation mobility, threshold voltage (V _th ) _, on-off current ratio (I _{on / off} ), and swing when heat treated at).

Referring to FIG. 6, it can be seen that the oxide semiconductor thin film is improved in electrical properties when not coated with sodium hypochlorite solution.

Specifically, in the case of saturation mobility, there is a relationship between defect sites such as oxygen vacancy and trap sites on an interface, such as oxygen vacancy in the active layer, and sodium hypochlorite solution. It can be seen that the charge mobility is the highest when the oxide semiconductor thin film coated with a heat treatment at 150 ℃.

The threshold voltage (V _th ) is related to the driving voltage of the device. When the oxide semiconductor thin film coated with sodium hypochlorite solution is heat-treated at 100 ° C., the device is driven with the smallest threshold voltage (V _th ). The degradation of the device can be reduced and the efficiency can be increased.

In addition, the on-off current ratio (I _{on / off} ) is the highest on-off current ratio when the oxide semiconductor thin film coated with sodium hypochlorite solution is heat-treated at 100 ℃, which is the amount of current flowing through the semiconductor It can be seen that can effectively control the.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

100, 200: oxide thin film transistor
110, 210: Substrate
120, 260: gate electrode
130, 250: gate insulating layer
140, 240: oxide semiconductor thin film
150, 220: source electrode
160, 230: drain electrode

Claims (8)

A gate electrode formed on the substrate;
A gate insulating layer formed on the gate electrode;
An oxide semiconductor thin film on the gate insulating layer; And
Source and drain electrodes formed on the oxide semiconductor thin film spaced apart from each other
Including,
Coating the activated sodium hypochlorite solution through a light source on the oxide semiconductor thin film and activating the oxide semiconductor thin film formed by heat treatment;
An oxide thin film transistor characterized in that the threshold voltage and the on-off current ratio is changed according to the heat treatment temperature.
The method of claim 1,
The heat treatment is an oxide thin film transistor, characterized in that performed at a temperature in the range of 25 ℃ to 300 ℃.
The method of claim 2,
The heat treatment of the oxide thin film transistor, characterized in that performed for 5 to 60 minutes.
The method of claim 1,
Irradiation of the light source is an oxide thin film transistor, characterized in that performed for 5 to 60 minutes.
The method of claim 1,
The amount of the sodium hypochlorite solution is an oxide thin film transistor, characterized in that 0.1mL to 5mL.
The method of claim 1,
The oxide semiconductor thin film includes amorphous indium gallium-zinc oxide (a-IGZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium tin oxide (ITO), zinc tin oxide (ZTO). , Silicon indium zinc oxide (SIZO), gallium zinc oxide (GZO), hafnium indium zinc oxide (HIZO), zinc indium tin oxide (ZITO) and aluminum zinc tin oxide (AZTO) Oxide thin film transistor.
A source electrode and a drain electrode formed spaced apart from each other on the substrate;
An oxide semiconductor thin film formed on the source electrode and the drain electrode;
A gate insulating layer formed on the oxide semiconductor thin film; And
A gate electrode formed on the gate insulating layer
Including,
Coating the activated sodium hypochlorite solution through a light source on the oxide semiconductor thin film and activating the oxide semiconductor thin film formed by heat treatment;
An oxide thin film transistor characterized in that the threshold voltage and the on-off current ratio is changed according to the heat treatment temperature.
Forming a gate electrode on the substrate;
Forming a gate insulating layer formed on the gate electrode;
Forming an oxide semiconductor thin film on the gate insulating layer;
Coating the activated sodium hypochlorite solution on the oxide semiconductor thin film through a light source;
Activating the oxide semiconductor thin film through heat treatment;
And
Forming a source electrode and a drain electrode spaced apart from each other on the oxide semiconductor thin film;
Including,
A method of manufacturing an oxide thin film transistor, wherein an oxide thin film transistor having a threshold voltage and an on-off current ratio is changed according to a heat treatment temperature.

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