KR20190129223A - Oxide semiconductor thin film photo transistor and method of manufacturing the same - Google Patents

Abstract

Disclosed are an oxide semiconductor thin film photo transistor and a method for manufacturing the same. According to an embodiment of the present invention, the oxide semiconductor thin film photo transistor comprises: a gate electrode formed on a substrate; a gate insulating layer formed on the gate electrode; a first oxide thin film including a first nanowire structure formed on the gate insulating layer; a first oxide semiconductor layer formed on the first oxide thin film; a second oxide thin film including a second nanowire structure formed on the first oxide semiconductor layer; a second oxide semiconductor layer formed on the second oxide thin film; and a source/drain electrode formed on the second oxide semiconductor layer. Each of the first and second oxide thin films includes a highly defective interface (HDI) in each thin film and absorbs light of a visible light area through the HDI.

Description

OXIDE SEMICONDUCTOR THIN FILM PHOTO TRANSISTOR AND METHOD OF MANUFACTURING THE SAME

The present invention relates to an oxide semiconductor thin film phototransistor and a method of manufacturing the same, and more particularly, a first oxide thin film and a first oxide semiconductor layer having a first nanowire structure formed between a gate insulating layer and a first oxide semiconductor layer. By forming a second oxide thin film having a second nanowire structure formed between the second oxide semiconductor layer, the present invention relates to an oxide semiconductor thin film phototransistor having improved visible light absorption and electrical characteristics, and a method of manufacturing the same.

Recently, as a display has been manufactured to have a high resolution and a large area, research on transistors to be applied to a backplane continues, and a technology using an oxide semiconductor as a semiconductor of a transistor has been developed.

Oxide thin film transistors have high mobility, low off-current, and excellent uniformity compared to conventional amorphous silicon (a-Si) thin film transistors.

In addition, an oxide semiconductor used as a channel layer region of an oxide thin film transistor has an optoelectronic structure using a characteristic of absorbing light when generating light in a UV region of 420 nm or less due to a wide bandgap energy (> 3 eV), thereby generating a photocurrent. A lot of research on the device is in progress, and in particular, it is possible to manufacture a flexible and transparent device such as a plastic substrate.

However, transparent materials have limitations that cannot be applied to a device for detecting visible light, and thus, deposition of additional materials capable of absorbing visible light is indispensable.

Republic of Korea Patent Publication No. 10-1441808 (2014.09.11) "Flexible zinc oxide transparent electrode composite with metal nanowires and thin film solar cell using the same"

Christoph Hunger, "Transparent Metal Network with Low Haze and High Figure of Merit applied to Front and Back Electrodes in Semitransparent ITO-free Polymer Solar Cells" (2015.05.05) K.D.M. Rao, "Fabrication of Large Area, High-Performance, Transparent Conducting Electrodes Using a Spontaneously Formed Crackle Network as Template" (2014.05.11)

Embodiments of the present invention are to provide an oxide semiconductor thin film phototransistor and a method of manufacturing the same by inducing arbitrary defects by sandwiching an oxide thin film including a nanowire structure between an insulating layer and an oxide semiconductor layer.

Embodiments of the present invention provide an oxide semiconductor thin film phototransistor and a method of manufacturing the same that can be applied as a transparent RGB image sensor.

An oxide semiconductor thin film phototransistor 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; A first oxide thin film including a first nanowire structure formed on the gate insulating layer; A first oxide semiconductor layer formed on the first oxide thin film; A second oxide thin film including a second nanowire structure formed on the first oxide semiconductor layer; A second oxide semiconductor layer formed on the second oxide thin film; And a source / drain electrode formed on the second oxide semiconductor layer, each of the first oxide thin film and the second oxide thin film including a highly defective interface (HDI) in the thin film, and through the defect interface. It is characterized by absorbing light in the visible light region.

The first oxide thin film and the second oxide thin film may be the same oxide material.

The first oxide thin film may be formed by depositing an oxide material on a nanostructure-based template formed by applying a solution in which nanostructures are dispersed on the insulating layer and then naturally drying, and then removing the nanostructure-based template.

The second oxide thin film may be formed by depositing an oxide material on a nanostructure-based template formed by applying a solution in which nanostructures are dispersed on the first oxide semiconductor layer and then naturally drying the nanostructure-based template. Can be.

The natural drying may be performed at 0 ° C to 500 ° C for 1 minute to 60 minutes.

The mass ratio of the nanostructure and the solvent of the solution in which the nanostructure is dispersed may be 0.1% to 80%.

The heat treatment may be performed in the range of 50 ℃ to 1000 ℃.

The heat treatment may be performed for 1 minute to 10 hours.

The first oxide thin film or the second oxide thin film may have a thickness of 1 nm to 30 nm.

The first oxide semiconductor layer or the second oxide semiconductor layer may be activated through heat treatment at 50 ° C to 1000 ° C.

The first oxide semiconductor layer or the second oxide semiconductor layer may have a thickness of 10 nm to 100 nm.

The first oxide semiconductor layer or the second oxide semiconductor layer is InGaZnO, ZnO, ZrInZnO, InZnO, AlInZnO, ZnO, InGaZnO ₄ , ZnInO, ZnSnO, In ₂ O ₃ , Ga ₂ O ₃ , HfInZnO, GaInZnO, HfO ₂ , SnO ₂ , WO ₃ , TiO ₂ , Ta ₂ O ₅ , In ₂ O ₃ SnO ₂ , MgZnO, ZnSnO ₃ , ZnSnO ₄ , CdZnO, CuAlO ₂ , CuGaO ₂ , Nb ₂ O _5, or TiSrO ₃ Can be.

The oxide material is MgO, CaO, SrO, BaO, Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , TiO ₂ , ZrO ₂ , HfO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , Cr2O3 , MoO ₃ , WO ₃ , Mn ₂ O ₃ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh ₂ O ₃ , NiO, PdO, PtO, CuO, Ag ₂ O, Au ₂ O ₃ , ZnO, Al ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , SiO ₂ , SnO ₂ or Bi ₂ O ₃ .

In another embodiment, a method of manufacturing an oxide semiconductor thin film phototransistor includes forming a gate electrode on a substrate; Forming a gate insulating layer on the gate electrode; Forming a first oxide thin film including a first nanowire structure on the gate insulating layer; Forming a first oxide semiconductor layer on the first oxide thin film; Forming a second oxide thin film including a second nanowire structure on the first oxide semiconductor layer; Forming a second oxide semiconductor layer on the second oxide thin film; And forming source / drain electrodes spaced apart from each other on the second oxide semiconductor layer, each of the first oxide thin film and the second oxide thin film including a highly defective interface (HDI) in the thin film. And absorbs light in the visible region through the defect interface.

The forming of the first oxide thin film on the gate insulating layer may include forming a nanostructure-based template by applying and naturally drying a solution in which the nanostructure is dispersed on the gate insulating layer; Depositing an oxide material on the formed nanostructure-based template and removing the nanostructure-based template to form a first oxide thin film including a first nanowire structure; And heat treating the first oxide thin film including the first nanowire structure.

The forming of the second oxide thin film on the first oxide semiconductor layer may include forming a nanostructure-based template by applying and naturally drying a solution in which the nanostructures are dispersed on the first oxide semiconductor layer; Depositing an oxide material on the formed nanostructure-based template and removing the nanostructure-based template to form a second oxide thin film including a second nanowire structure; And heat treating the second oxide thin film including the second nanowire structure.

Embodiments of the present invention can provide an oxide semiconductor thin film phototransistor and a method of manufacturing the same by inducing arbitrary defects by sandwiching an oxide thin film including a nanowire structure between an insulating layer and an oxide semiconductor layer.

Embodiments of the present invention can provide an oxide semiconductor thin film phototransistor and a method of manufacturing the same that can be applied as a transparent RGB image sensor.

1A to 1H illustrate a method of manufacturing an oxide semiconductor thin film phototransistor according to an exemplary embodiment of the present invention.
2A to 2E illustrate a method of manufacturing an oxide thin film including nanowire structures in a method of manufacturing an oxide semiconductor thin film phototransistor according to an embodiment of the present invention.
3A is a graph illustrating current-voltage transfer curves of an oxide semiconductor thin film phototransistor including a nanowire structure and an oxide semiconductor thin film phototransistor not including a nanowire structure, according to an embodiment of the present invention; 3B is a graph illustrating an output curve of an oxide semiconductor thin film phototransistor including a nanowire structure according to an exemplary embodiment of the present invention.
4A to 4C are graphs showing photoreactivity of an oxide semiconductor thin film phototransistor not including a nanowire structure, and FIGS. 4D and 4E are diagrams of an oxide semiconductor thin film phototransistor including a nanowire structure according to an exemplary embodiment. It is a graph showing photoreactivity.

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 changes, 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 semiconductor thin film phototransistor according to an embodiment of the present invention.

The oxide semiconductor thin film phototransistor 100 according to the exemplary embodiment of the present invention may include a substrate 110, a gate electrode 111, a gate insulating layer 112, a first oxide thin film 113, and a first oxide semiconductor layer 114. ), A second oxide thin film 115, a second oxide semiconductor layer 116, and source / drain electrodes 117 and 118.

1A and 1B, in the method of manufacturing the oxide semiconductor thin film phototransistor 100 according to an embodiment of the present disclosure, a substrate 110 is prepared, and a gate electrode 111 is formed on the prepared substrate 110. do.

As shown in FIG. 1A, the substrate 110 is a substrate for supporting various components of the oxide semiconductor thin film photo transistor, and the material thereof 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 111 may be formed on the substrate 110.

For example, the gate electrode 111 may be formed by vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, and 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 111 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 111 may use a p ⁺ -Si material as the gate electrode 111.

Referring to FIG. 1C, in the method of manufacturing the oxide semiconductor thin film photo transistor 100 according to the exemplary embodiment, a gate insulator 112 is formed on the gate electrode 120.

The gate insulating layer 112 may be formed by vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, or 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 112 may be 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 constituting the gate insulating layer 112 is not limited thereto, and other known materials and other methods may be used.

Referring to FIG. 1D, in the method of manufacturing the oxide semiconductor thin film phototransistor 100 according to the exemplary embodiment, a first oxide thin film 113 is formed on the gate insulating layer 112.

Specifically, the first oxide thin film 113 is coated with a solution in which the nanostructures are dispersed on the gate insulating layer 112 and then naturally dried to form a nanostructure-based template. Thereafter, after depositing an oxide material on the nanostructure-based template, the nanostructure-based template may be removed to form the first oxide thin film 113 including the first nanowire structure.

The first oxide thin film 113 may be formed to a thickness of 1 nm to 30 nm, preferably may be formed thinner than the first oxide semiconductor layer or the second oxide semiconductor layer, and may be formed to a thickness of 1 nm or less. In this case, there is a problem in that defects are not well formed.

The method of manufacturing the first oxide thin film 113 may be the same as the method of manufacturing the second oxide thin film 115 including the second nanowire structure of FIG. 1F, which will be described later. It may be formed by depositing the same oxide material as the second oxide thin film 115. A method of manufacturing the first oxide thin film 113 including the first nanowire structure will be described in detail with reference to FIGS. 2A to 2E.

Referring to FIG. 1E, in the method of manufacturing the oxide semiconductor thin film phototransistor 100 according to the exemplary embodiment, the first oxide semiconductor layer 114 is formed on the first oxide thin film 113.

Specifically, the first oxide semiconductor layer 114 may be activated by heat treatment after depositing the oxide semiconductor on the first oxide thin film 113, and may be formed to a thickness of 10 nm to 100 nm, preferably It may be formed thicker than the first oxide thin film or the second oxide thin film.

The oxide semiconductor 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 semiconductor may be 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 coated on the first oxide thin film 113 using any one of dip coating and zone casting, but the method is not limited thereto, and other known methods may be used.

The oxide semiconductor 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 such as zinc oxide (ZnO).

Specifically, the oxide semiconductor 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) or a combination thereof. However, the present invention is not limited thereto and may be made of various materials.

Heat treatment for activating the first oxide semiconductor layer 114 may be performed for 1 minute to 10 hours at a temperature in the range of 50 ℃ to 1000 ℃.

The first oxide semiconductor layer 114 and the second oxide semiconductor layer 116 may be made of the same or different materials, preferably, different materials.

When the first oxide semiconductor layer 114 and the second oxide semiconductor layer 116 are made of different materials from each other, the second oxide thin film sandwiched between the first oxide semiconductor layer 114 and the second oxide semiconductor layer 116. More defects can be formed in the 115, so that the absorbance of visible light of the oxide semiconductor thin film phototransistor can be improved than when made of the same material.

Referring to FIG. 1F, in the method of manufacturing the oxide semiconductor thin film phototransistor 100 according to the exemplary embodiment, a second oxide thin film 115 is formed on the first oxide semiconductor layer 114.

Specifically, the second oxide thin film 115 is coated with a solution in which the nanostructures are dispersed on the first oxide semiconductor layer 114 and then naturally dried to form a nanostructure-based template. Thereafter, after depositing an oxide material on the nanostructure-based template, the nanostructure-based template may be removed to form a second oxide thin film 115 including a second nanowire structure.

The second oxide thin film 115 may be formed to a thickness of 1 nm to 30 nm, preferably thinner than the first oxide semiconductor layer or the second oxide semiconductor layer, and may be formed to a thickness of 1 nm or less. In this case, there is a problem in that defects are not well formed.

The method of manufacturing the second oxide thin film 115 may be the same as the method of manufacturing the first oxide thin film 113 including the first nanowire structure of FIG. 1D, and the second oxide thin film 115 may be formed of the first oxide thin film 115. 1 may be formed by depositing the same oxide material as the oxide thin film 113.

A method of manufacturing the second oxide thin film 115 including the second nanowire structure will be described in detail with reference to FIGS. 2A to 2E.

Referring to FIG. 1G, in the method of manufacturing the oxide semiconductor thin film phototransistor 100 according to the exemplary embodiment, a second oxide semiconductor layer 116 is formed on the second oxide thin film 115.

The method of forming the second oxide semiconductor layer 116 may be the same as the method of forming the first oxide semiconductor layer 114.

Specifically, the second oxide semiconductor layer 116 may be activated by heat treatment for 1 minute to 10 hours at a temperature in the range of 50 ℃ to 1000 ℃ after depositing the oxide semiconductor on the second oxide thin film 115.

The second oxide semiconductor layer 116 may be formed to a thickness of 10 nm to 100 nm, and preferably may be formed thicker than the thickness of the first oxide thin film or the second oxide thin film.

The first oxide semiconductor layer 114 and the second oxide semiconductor layer 116 may be made of the same or different materials, preferably, different materials.

When the first oxide semiconductor layer 114 and the second oxide semiconductor layer 116 are made of different materials from each other, the second oxide thin film sandwiched between the first oxide semiconductor layer 114 and the second oxide semiconductor layer 116. More defects can be formed in the 115, so that the absorbance of visible light of the oxide semiconductor thin film phototransistor can be improved than when made of the same material.

Referring to FIG. 1H, in the method of manufacturing the oxide semiconductor thin film photo transistor 100 according to an exemplary embodiment, the source electrode 117 and the drain electrode 118 are spaced apart from each other on the second oxide semiconductor layer 116. It is formed.

The source electrode 117 and the drain electrode 118 are aluminum (Al), aluminum alloy (Al alloy), tungsten (W), copper (Cu), nickel (Ni), chromium (Cr), molybdenum (Mo), titanium Low resistance conductive materials such as (Ti), platinum (Pt) or tantalum (Ta) may be used.

In addition, the source electrode 117 and the drain electrode 118 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 117 and the drain electrode 118 may be formed in a multilayer structure in which two or more conductive materials are stacked.

As described above, in the oxide semiconductor thin film phototransistor according to the exemplary embodiment of the present invention, a first oxide thin film is sandwiched between an insulating layer and a first oxide semiconductor layer, and a first oxide semiconductor layer and a second oxide semiconductor layer. The second oxide thin film is sandwiched therebetween, and the first oxide thin film and the second oxide thin film include a nanowire structure, and each includes a highly defective interface (HDI).

Therefore, the oxide semiconductor thin film phototransistor according to the embodiment of the present invention can absorb light in the visible region through the defect interface.

In addition, the thickness of the first oxide thin film or the second oxide thin film of the oxide semiconductor thin film phototransistor according to an embodiment of the present invention may be thinner than the first oxide semiconductor layer or the second oxide semiconductor layer, and the oxide semiconductor thin film photo The transistor may be formed to a thickness of 1 μm or less.

Hereinafter, a method of forming an oxide thin film including a nanowire structure will be described in detail with reference to FIGS. 2A to 2E.

2A to 2E illustrate a method of manufacturing an oxide thin film including a nanowire structure in a method of manufacturing an oxide semiconductor thin film phototransistor according to an embodiment of the present invention.

2A and 2B, in the method of manufacturing an oxide thin film including a nanowire structure, the nanostructure is dispersed on a substrate 210 and then naturally dried.

The mass ratio of the nanostructure and the solvent of the solution 220 in which the nanostructure is dispersed may be 0.1% to 80%.

The nanostructure may have a particle size of 1nm to 1000nm, SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , SnO ₂ , Sb ₂ O ₅ , Nb ₂ O ₃ , Y ₂ O ₃ , ZnO, Ag and It may be made of any one or combination of Ni, but is not limited thereto, and may be made of various materials.

The method of coating the nanostructure-dispersed solution 220 on the substrate 210 is a method used in the art, but the method is not particularly limited, but spin coating or spray coating. , Inkjet coating, slit coating or deep coating, roll-to-roll and screen printing can be used. For example, spin coating may be used.

When using a spin coating method, a solution 220 in which the nanostructures are dispersed may be applied onto the substrate 210 at a speed of 100 rpm to 20,000 rpm.

As shown in FIG. 2B, the nanostructure-based template 230 may be randomly formed in an island form by applying a solution 210 having nanostructures dispersed thereon onto a substrate 210 and then naturally drying the same. Can be.

Natural drying of the solution 210 in which the nanostructures are dispersed may be performed for 1 minute to 60 minutes in the range of 0 ° C to 500 ° C.

Referring to FIG. 2C, a method of manufacturing a first nanowire structure in a method of manufacturing an oxide semiconductor thin film phototransistor according to an embodiment of the present invention deposits an oxide material 240 on a nanostructure-based template 230.

Oxide material 240 includes MgO, CaO, SrO, BaO, Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , TiO ₂ , ZrO ₂ , HfO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , Cr ₂ O ₃ , MoO ₃ , WO ₃ , Mn ₂ O ₃ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh ₂ O ₃ , NiO, PdO, PtO, CuO, Ag ₂ O, Au ₂ O ₃ , ZnO, Al _It may be made of any one or a combination of ₂ O ₃ , Ga ₂ O ₃ , In ₂ O ₃ , SiO ₂ , SnO ₂ or Bi ₂ O ₃ , but is not limited thereto, and may be made of various materials.

The oxide material 240 is formed on the nanostructure-based template 230 by vacuum deposition, chemical vapor deposition, physical vapor deposition, atomic layer deposition, organic Metal Organic Chemical Vapor Deposition, Plasma-Enhanced Chemical Vapor Deposition, Molecular Beam Epitaxy, Hydride Vapor Phase Epitaxy, Sputtering, Spin It may be deposited using at least one method of spin coating, dip coating and zone casting.

2D and 2E, after the nanostructure-based template 230 on which the oxide material 240 is deposited is removed from the substrate 210, an oxide thin film 260 including a nanowire structure is formed on the substrate. Then, heat treatment (not shown) is performed.

The nanostructure-based template may be removed using at least one of lift off, ultrasonication, wet etch, and dry etch. The present invention is not limited thereto and may be removed using various methods.

2A to 2E, after depositing the solution 220 in which the nanostructures are dispersed on the substrate 210, and depositing the oxide material 240 on the nanostructure-based template 230 formed by natural drying. The process of removing the nanostructure-based template may be repeated at least one or more times, preferably three to four times.

When the process of repeatedly forming the oxide thin film including the nanowire structure shown in FIGS. 2A to 2E is repeated, the density of the nanowires is increased and thus the number of defects is increased, thereby improving the absorption of visible light. Can be.

However, when repeated four or more times, the shape of the nanowires does not appear, and thus a defect is not formed, and thus there is a problem that the electrical characteristics of the oxide semiconductor thin film phototransistor are degraded.

The oxide thin film 260 including the nanowire structure may have a thickness of 1 nm to 30 nm, preferably thinner than the oxide semiconductor layer, and when formed to a thickness of 1 nm or less, defects may be well formed. There is a problem.

The heat treatment may be performed for 1 minute to 10 hours at a temperature in the range of 50 ℃ to 1000 ℃.

Hereinafter, the characteristics of the oxide semiconductor thin film phototransistor according to an embodiment of the present invention will be described.

( Example )

(Substrate and gate Insulation layer  Ready)

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

SiO ₂ was formed as a gate insulating layer on the substrate on which the gate electrode was formed using a thermal oxidation method to prepare a SiO ₂ / p ⁺ -Si substrate.

Thereafter, in order to remove organic substances or impurities that may be formed on the surface of the SiO ₂ / p ⁺ -Si substrate, washing is performed for 10 minutes using an ultrasonic cleaner in the order of acetone, methanol, and DI water. The remaining liquid was removed using N ₂ gas.

Hydrophilic surface for increasing the wettability of the solution by generating a large amount of OH ^- groups through the surface treatment for 15 minutes using a Deep UV lamp (wavelength 185nm, 254nm) on the substrate with the gate electrode and the gate insulating layer as described above Formed.

(Formation of First Oxide Thin Film)

The nanostructure solution was coated on the substrate on which the gate electrode and the gate insulating layer were formed by using spin coating. The nanostructure solution was a colloidal silica (HS-30 of LUDOX Co., Ltd.) in which 12 nm-sized SiO ₂ nanoparticles were dispersed in a content of 30%.

Thereafter, the mixture was dried at room temperature for about 5 minutes to form an island-based nanostructure-based template.

After depositing the oxide material using RF Magnetron Sputtering on the substrate on which the nanostructure-based template was formed, the nanostructure-based template was removed by ultrasonication on DI water and then subjected to 1 at a temperature of 300 ° C. Heat treatment was performed for a time.

(First oxide Semiconductor layer  formation)

After depositing Indium-Gallium-Zinc-Oxide (IGZO) using RF Magnetron Sputtering on the formed first oxide thin film, the first oxide semiconductor layer is subjected to heat treatment for 1 hour at a temperature of 300 ° C. Activated.

(Formation of Second Oxide Thin Film)

The second oxide thin film is formed on the first oxide semiconductor layer in the same manner as the first oxide thin film.

 (Second oxide Semiconductor layer  formation)

The second oxide semiconductor layer is formed on the second oxide thin film in the same manner as the first oxide semiconductor layer.

(sauce/ drain  Formation of electrodes)

An oxide thin film phototransistor is deposited by depositing a source / drain electrode having a width and a length of 1000 μm and 150 μm, respectively, using a shadow mask and RF magnetron sputtering on the second oxide semiconductor layer. Completed.

3A is a graph illustrating current-voltage transfer curves of an oxide semiconductor thin film phototransistor including a nanowire structure and an oxide semiconductor thin film phototransistor not including a nanowire structure, according to an embodiment of the present invention; 3B is a graph illustrating an output curve of an oxide semiconductor thin film phototransistor including a nanowire structure according to an exemplary embodiment of the present invention.

Referring to FIG. 3A, an oxide semiconductor thin film phototransistor including a nanowire structure (red graph) has a higher off current and a higher on current compared to an oxide semiconductor thin film phototransistor including a nanowire structure (black graph). It can be seen that low.

It can be seen that the oxide semiconductor thin film phototransistor including the nanowire structure includes the defective interface (HDI) in the first oxide thin film and the second oxide thin film, thereby improving electrical characteristics of the oxide semiconductor thin film phototransistor.

Referring to FIG. 3B, it can be seen that the oxide semiconductor thin film phototransistor including the nanowire structure is sure to increase or decrease the current according to the voltage change. From this, it can be seen that the electrical characteristics of the oxide semiconductor thin film phototransistor are improved.

4A to 4C are graphs showing photoreactivity of an oxide semiconductor thin film phototransistor not including a nanowire structure, and FIGS. 4D and 4E are diagrams of an oxide semiconductor thin film phototransistor including a nanowire structure according to an exemplary embodiment. It is a graph showing photoreactivity.

4A to 4C, lasers of three wavelength bands of red (635 nm), green (532 nm) and blue (405 nm) are used to measure photoreactivity of an oxide semiconductor thin film phototransistor including no nanowire structure. It was.

The drain voltage was fixed at 1.95 eV for Red, 2.33 eV for Green, and 3.06 eV for Blue, and the irradiation intensity of the laser was varied by 1 mW, 3 mW, 5 mW, and 10 mW for each laser.

In the case of the oxide semiconductor thin film phototransistor not including the nanowire structure, when the red laser and the green laser are irradiated, it can be seen that the transfer characteristics of the oxide semiconductor thin film phototransistor are hardly shown despite the change in irradiation intensity.

On the other hand, when the blue laser is irradiated, it can be seen that the off current is greatly changed by absorbing light due to high energy.

Therefore, it can be seen that the oxide semiconductor thin film phototransistor not including the nanowire structure does not absorb light in a low energy visible light region due to a wide bandgap of 3 eV or more of IGZO.

4D and 4E, two wavelength bands of red (635 nm) and green (532 nm) lasers are used to measure photoreactivity of an oxide semiconductor thin film phototransistor including a nanowire structure according to an exemplary embodiment of the present invention. Was used.

The drain voltage was fixed at 1.95 eV for Red and 2.33 eV for Green, respectively, and the irradiation intensity of the laser was varied by 1 mW, 3 mW, 5 mW, and 10 mW for each laser.

However, in the case of the blue laser, the current change also occurred in the oxide semiconductor thin film phototransistor not including the nanowire structure, and thus the blue laser was not irradiated.

In the oxide semiconductor thin film phototransistor including a nanowire structure according to an exemplary embodiment of the present invention, as the irradiation intensity of the red laser and the green laser increases, the threshold voltage moves in the negative direction and the off current increases. .

From this, it can be seen that even in the low energy visible light region, the oxide thin film including the nanowire structure absorbs light from defects in the thin film, thereby improving electrical characteristics of the oxide semiconductor thin film phototransistor.

As described above, although the present invention has been described with reference to limited embodiments and drawings, 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: oxide semiconductor thin film phototransistor
110: substrate
111: gate electrode
112: gate insulating layer
113: first oxide thin film
114: first oxide semiconductor layer
115: second oxide thin film
116: second oxide semiconductor layer
117 source electrode
118: drain electrode

Claims (16)

A gate electrode formed on the substrate;
A gate insulating layer formed on the gate electrode;
A first oxide thin film including a first nanowire structure formed on the gate insulating layer;
A first oxide semiconductor layer formed on the first oxide thin film;
A second oxide thin film including a second nanowire structure formed on the first oxide semiconductor layer;
A second oxide semiconductor layer formed on the second oxide thin film; And
Source / drain electrodes formed on the second oxide semiconductor layer
Including,
And the first oxide thin film and the second oxide thin film each include a highly defective interface (HDI) in the thin film and absorb light in the visible region through the defective interface. The method of claim 1,
And the first oxide thin film and the second oxide thin film are the same oxide material. The method of claim 1,
The first oxide thin film is formed by depositing an oxide material on a nanostructure-based template formed by applying a solution in which the nanostructures are dispersed on the gate insulating layer and then naturally drying the nanostructure-based template. An oxide semiconductor thin film phototransistor. The method of claim 1,
The second oxide thin film is formed by depositing an oxide material on a nanostructure-based template formed by applying a solution in which the nanostructures are dispersed on the first oxide semiconductor layer and then naturally drying the nanostructure-based template. An oxide semiconductor thin film photo transistor, characterized in that. The method according to claim 3 or 4,
The natural drying is an oxide semiconductor thin film photo transistor, characterized in that performed for 1 to 60 minutes at 0 ℃ to 500 ℃. The method according to claim 3 or 4,
The mass ratio of the nanostructure and the solvent of the solution in which the nanostructure is dispersed is an oxide semiconductor thin film photo transistor, characterized in that. The method according to claim 3 or 4,
The heat treatment is an oxide semiconductor thin film photo transistor, characterized in that performed in the range of 50 ℃ to 1000 ℃. The method according to claim 3 or 4,
The heat treatment is an oxide semiconductor thin film transistor, characterized in that performed for 1 minute to 10 hours. The method of claim 1,
And the first oxide thin film or the second oxide thin film has a thickness of 1 nm to 30 nm. The method of claim 1,
The first oxide semiconductor layer or the second oxide semiconductor layer is an oxide semiconductor thin film transistor, characterized in that activated through a heat treatment of 50 ℃ to 1000 ℃. The method of claim 1,
And the first oxide semiconductor layer or the second oxide semiconductor layer has a thickness of 10 nm to 100 nm. The method of claim 1,
The first oxide semiconductor layer or the second oxide semiconductor layer is InGaZnO, ZnO, ZrInZnO, InZnO, AlInZnO, ZnO, InGaZnO ₄ , ZnInO, ZnSnO, In ₂ O ₃ , Ga ₂ O ₃ , HfInZnO, GaInZnO, HfO ₂ , SnO ₂ , WO ₃ , TiO ₂ , Ta ₂ O ₅ , In ₂ O ₃ SnO ₂ , MgZnO, ZnSnO ₃ , ZnSnO ₄ , CdZnO, CuAlO ₂ , CuGaO ₂ , Nb ₂ O _5, or at least one of TiSrO ₃ An oxide semiconductor thin film photo transistor, characterized in that. The method of claim 2,
The oxide material is MgO, CaO, SrO, BaO, Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , TiO ₂ , ZrO ₂ , HfO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , Cr2O3 , MoO ₃ , WO ₃ , Mn ₂ O ₃ , Fe ₂ O ₃ , Co ₃ O ₄ , Rh ₂ O ₃ , NiO, PdO, PtO, CuO, Ag ₂ O, Au ₂ O ₃ , ZnO, Al ₂ O ₃ And at least one of Ga ₂ O ₃ , In ₂ O ₃ , SiO ₂ , SnO ₂ or Bi ₂ O ₃ . Forming a gate electrode on the substrate;
Forming a gate insulating layer on the gate electrode;
Forming a first oxide thin film including a first nanowire structure on the gate insulating layer;
Forming a first oxide semiconductor layer on the first oxide thin film;
Forming a second oxide thin film including a second nanowire structure on the first oxide semiconductor layer;
Forming a second oxide semiconductor layer on the second oxide thin film; And
Forming a source / drain electrode spaced apart from each other on the second oxide semiconductor layer
Including,
The first oxide thin film and the second oxide thin film each comprise a highly defective interface (HDI) in the thin film, the oxide semiconductor thin film phototransistor characterized in that absorbing the light in the visible region through the defect interface. Way. The method of claim 14,
Forming a first oxide thin film including a first nanowire structure on the gate insulating layer
Forming a nanostructure-based template by applying and naturally drying a solution in which nanostructures are dispersed on the gate insulating layer;
Depositing an oxide material on the formed nanostructure-based template and removing the nanostructure-based template to form a first oxide thin film including a first nanowire structure; And
Heat-treating a first oxide thin film including the first nanowire structure
Method for producing an oxide semiconductor thin film phototransistor comprising a. The method of claim 14,
Forming a second oxide thin film including a second nanowire structure on the first oxide semiconductor layer
Forming a nanostructure-based template by applying and naturally drying a solution in which nanostructures are dispersed on the first oxide semiconductor layer;
Depositing an oxide material on the formed nanostructure-based template and removing the nanostructure-based template to form a second oxide thin film including a second nanowire structure; And
Heat-treating a second oxide thin film including the second nanowire structure
Method for producing an oxide semiconductor thin film phototransistor comprising a.

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