KR100592277B1 - Thin film transistor, method of manufacturing same and flat panel display device having same - Google Patents

Abstract

The present invention, a substrate; A gate electrode formed on the substrate; A gate insulating layer formed on the gate electrode; A source / drain electrode formed on the gate insulating layer to be insulated from the gate electrode; And an organic semiconductor layer in contact with the source / drain electrode and insulated from the gate electrode.

 A junction layer is interposed between the gate insulating layer and the source / drain electrode, and a work function of the junction layer is smaller than a work function of the source / drain electrode, and at least a portion of the junction layer in contact with the organic semiconductor layer is Provided are a thin film transistor, a method of manufacturing the same, and a flat panel display device having the same, wherein the oxidation part is an oxidation treatment.

Description

A thin film transistor, a method for manufacturing the same, and a flat panel display device having the same}

1A is a schematic cross-sectional view of an organic thin film transistor according to the prior art,

FIG. 1B is a schematic cross sectional view showing a state in operation of reference numeral “A” of FIG. 1A;

2A to 2F are diagrams illustrating a process of manufacturing a thin film transistor according to an embodiment of the present invention;

3A and 3B are partial enlarged views of reference numeral “B” of FIG. 2F, showing diagrams of an operating configuration according to oxide group concentration and / or thickness;

4 is a schematic partial cross-sectional view of an organic electroluminescent display device having a thin film transistor according to another embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

110, 210 ... substrate 120, 220 ... gate electrode

130, 230 ... gate insulation layer 140, 240 ... bond layer

140a, b, 240a ... oxidized parts 150a, b, 250a, b ... source / drain electrodes

160, 260 ... organic semiconductor layers 160a, b, 260a, b ... source / drain regions

160c, 260c ... channel area 161 ... stacked

270 ... protective layer 271 ... via hole

300 ... organic electroluminescent device 310 ... first electrode layer

320 pixel defining layer 321 pixel opening

330 organic electroluminescent unit 340 second electrode layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor and a flat panel display device having the same. More particularly, the present invention relates to a structure for increasing electrical bonding between the source / drain electrodes and the lower stack and facilitating electrical communication between the source / drain electrodes. A thin film transistor and a flat panel display device having the same.

Thin film transistors used in flat panel display devices such as liquid crystal display devices, organic electroluminescent display devices, or inorganic electroluminescent display devices (hereinafter referred to as TFTs) are used to drive switching elements and pixels that control the operation of each pixel. Used as a drive element.

Such a conventional TFT has a semiconductor layer having a source / drain region doped with a high concentration of impurities, a channel region formed between the source / drain regions, and a region insulated from the semiconductor layer and corresponding to the channel region. The gate electrode is positioned, and the source / drain electrodes are in contact with the source / drain regions, respectively.

On the other hand, the demand for TFT is required not only in display devices but also in various fields. For example, recently, it is used in various fields such as smart cards, e-papers, roll-up displays, etc., which are required for thin electronic devices provided therein. Since the common feature is flexibility, the substrate forming the thin film transistor is required to be a substrate having flexibility such as a plastic substrate.

By the way, when forming the semiconductor layer of the inorganic material like the prior art, the high temperature process of 300 degreeC or more is accompanied, and the plastic board | substrate vulnerable to heat cannot be used.

Low temperature polysilicon manufacturing processes have been developed that meet the design specifications and enable low temperature processes, but have not yet met sufficient manufacturing requirements.

In order to solve this problem, organic semiconductors have recently emerged. The organic semiconductor can be formed in a low temperature process and has the advantage of realizing a low-cost thin film transistor.

In Japanese Patent Laid-Open No. 2003-282883, a bottom-contact in which an organic semiconductor layer is formed on one surface of a gate insulating layer covering a gate electrode, and a source / drain electrode is formed on one surface of the organic semiconductor layer. An organic semiconductor transistor having a structure is disclosed.

Japanese Patent Laid-Open Publication No. 2003-092410 discloses a thin film transistor having a gate electrode at a corresponding position in a channel region, and a top-contact organic thin film transistor composed of an organic compound having a radical in a channel region. Is disclosed.

In the organic thin film transistor according to the prior art, a noble metal such as gold (Au) is mainly used as the source / drain electrode to facilitate electrical contact between the source / drain electrode and the organic semiconductor layer. Precious metals such as (Au) have a disadvantage in that the adhesion to a laminated film disposed below, in particular, an insulating layer formed of a material such as SiNx or SiO2 is considerably degraded.

Meanwhile, Korean Patent Laid-Open Publication No. 2003-3067 discloses an inorganic thin film transistor having a junction improving layer made of Ti or the like in order to improve bonding with an insulating layer of SiO 2 disposed under a platinum (Pt) electrode. have.

Thus, as a solution to the disadvantage of the thin film transistor having the organic semiconductor layer, an organic thin film transistor having a junction improving layer is shown in Figure 1a. The gate electrode 12 and the gate insulating layer 13 are formed on one surface of the substrate 11, and the source / drain electrodes 15a and b and the organic semiconductor layer 16 are disposed on one surface of the gate insulating layer 13. Is formed, and the junction improving layer 14 made of a material such as Ti is disposed between the source / drain electrodes 15a and b and the gate insulating layer 13.

The operation of the organic thin film transistor is performed by electrical signals applied to the gate electrode 12 and the source / drain electrodes 15a and b. In FIG. 1B, as an example of the operation of the organic thin film transistor, reference numeral “A” of FIG. A schematic partial enlarged view of the portion indicated by.

If the organic semiconductor active layer 16 is a p-type semiconductor, a negative voltage is applied to the gate electrode 12, and a voltage is applied to the source / drain 15a, b, the organic contacting the gate insulating layer 13 Under the semiconductor layer 16, an accumulation layer 16a, in which a lot of charge carriers are collected, is formed. However, a significant work function difference occurs between Ti and the organic semiconductor layer 16, which is a material constituting the junction improving layer 14, and thus, it is difficult to achieve smooth electrical communication. Therefore, when the accumulation layer is formed adjacent to the gate insulating layer 13 by the organic semiconductor layer 16 as described above, the electrical signal transmitted from the source electrode 15a passes through the channel region of the organic semiconductor layer 16. It is not delivered to the drain electrode 15b and / or is weakly delivered.

When such a thin film transistor is used as a thin film transistor for selecting a pixel of a flat panel display device or as a thin film transistor for driving a pixel, a desired pixel is not selected or a desired electrical signal is not applied to the selected pixel. It can also reduce the.

Disclosure of Invention An object of the present invention is to provide a thin film transistor, a method of manufacturing the same, and a flat panel display device having the same, which solves the above problems and facilitates electrical communication between source and drain electrodes.

In order to achieve the above object, according to one aspect of the invention,

Board;

A gate electrode formed on the substrate;

A gate insulating layer formed on the gate electrode;

A source / drain electrode formed on the gate insulating layer to be insulated from the gate electrode; And

And an organic semiconductor layer in contact with the source / drain electrode and insulated from the gate electrode.

 A junction layer is interposed between the gate insulating layer and the source / drain electrode, and a work function of the junction layer is smaller than a work function of the source / drain electrode, and at least a portion of the junction layer in contact with the organic semiconductor layer is Provided is a thin film transistor, which is an oxidation treated oxidation portion.

According to another aspect of the invention, the source / drain electrode is gold (Au), palladium (Pd), platinum (Pt), nickel (Ni), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium A thin film transistor comprising at least one of (Os) is provided.

According to another aspect of the present invention, the junction layer provides a thin film transistor, characterized in that it comprises at least one of titanium (Ti), chromium (Cr), aluminum (Al), molybdenum (Mo).

According to another aspect of the invention, the organic semiconductor layer, pentacene (pentacene), tetracene (tetracene), atracene (anthracene), naphthalene (alpha) -6-thiophene, perylene (perylene) And derivatives thereof, rubrene and derivatives thereof, coronene and derivatives thereof, perylene tetracarboxylic diimide and derivatives thereof, and perylenetetracarboxylic carboxylic hydride ( perylene tetracarboxylic dianhydride) and its derivatives, polythiophene and its derivatives, polyparaphenylenevinylene and its derivatives, polyparaphenylene and its derivatives, polyfluorene and its derivatives, polythiophenevinylene and its derivatives, poly Thiophene-heterocyclic aromatic copolymers and derivatives thereof, oligoacenes and derivatives thereof of naphthalene, oligothiophenes and derivatives thereof of alpha-5-thiophene, phthalocyanines with or without metals, and Derivatives thereof, pyromellitic dianhydrides and derivatives thereof, pyromellitic diimides and derivatives thereof, perylenetetracarboxylic acid dianhydrides and derivatives thereof and perylenetetracarboxylic diimides and derivatives thereof It provides a thin film transistor comprising any one.

According to still another aspect of the present invention, there is provided a flat panel display device including the thin film transistor and having one or more pixels.

According to another aspect of the invention, the pixel provides a flat panel display device comprising a first electrode layer, a second electrode layer and an organic electroluminescence interposed therebetween.

According to another aspect of the invention, the gate electrode formed on the substrate; Providing a gate insulating layer formed on the gate electrode;

Forming a bonding layer on one surface of the gate insulating layer;

Forming a source / drain electrode on one surface of the bonding layer;

Forming an organic semiconductor layer in contact with said source / drain electrode,

And oxidizing at least a portion of the junction layer in contact with the organic semiconductor layer before forming the organic semiconductor layer.

According to yet another aspect of the present invention, the oxidation treatment step is a thin film transistor manufacturing method characterized in that the step after the source / drain electrode forming step is formed before the organic semiconductor layer forming step.

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

2A to 2F illustrate a manufacturing process of a thin film transistor according to an exemplary embodiment of the present invention.

A gate electrode 120 on one surface of the substrate 110; A gate insulating layer 130 is formed to insulate the gate electrode 120 from the source / drain electrode 140 (see FIG. 2B) to be formed later. Substrate 110 may be a glass material, for example polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyether imide ), Polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose tri acetate (TAC), cellulose acetate propinonate (CAP Plastic ash), and the like.

The gate electrode 120 is formed on one surface of the substrate 110. In some cases, a buffer layer (not shown) may be interposed between the gate electrode 120 and the substrate 110. The gate electrode 120 may be a conductive metal such as MoW, Al, Cr, Al / Cr, conductive polyaniline, conductive poly pirrole, conductive polythiopjene, polyethylene deoxythiophene, or polyethylene. Various conductive polymers such as dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) may be used, such as adhesion to the substrate 110, flatness of the thin films formed on the gate electrode 120, processability for patterning, and subsequent processing. Appropriate materials should be selected in consideration of resistance to the chemicals used.

The gate insulating layer 130 to insulate the gate electrode 120 from the source / drain electrode 140 formed later may be, for example, SiO 2, SiN x, Al 2 O 3, Ta 2 O 5, BZT, or PZT by chemical vapor deposition or sputtering. It may be composed of an inorganic insulating layer such as, or may be composed of an organic insulating layer such as BCB, polyimide, parylene, etc. by spin coating or thermal evaporation process, in some cases a plurality of layers Various configurations are possible, and the like, and it is preferable to select a material having excellent dielectric constant along with insulating properties and having the same or similar thermal expansion coefficient as the substrate.

As shown in FIGS. 2A and 2B, in order to form the bonding layer 140 (see FIG. 2C), a material layer 140 ′ constituting the bonding layer is formed on one surface of the gate insulating layer 130. The bonding layer 140 is formed through a suitable patterning process.

The bonding layer 140 is to increase the bonding between the source / drain electrodes 150a and 150b formed later and the gate insulating layer 130 disposed below, and may include titanium (Ti), chromium (Cr), and aluminum ( Al) and molybdenum (Mo) may be provided. That is, the bonding layer 140 may be formed of a single material of any one of the above materials, may be composed of an oxide or nitride such as TiN, TiO 2, or may include two or more materials such as TiAlN. Configuration is possible.

After the bonding layer 140 is formed, as shown in FIGS. 2C and 2D, the source / drain electrode material layer is formed on one surface including the bonding layer 140, and then the source / drain electrode is formed through an appropriate patterning process. 150a, 150b) are formed. As a material of the source / drain electrodes 150a and 150b, a work function is more than a work function of the junction layer 140 to enable smooth movement of charge carriers with an organic semiconductor layer 160 (see FIG. 2F) to be formed later. With one or more of large materials such as gold (Au), palladium (Pd), platinum (Pt), nickel (Ni), rhodium (Rh), ruthenium (Ru), iridium (Ir), osmium (Os) It is desirable to.

After the source / drain electrodes 150a and 150b are formed, the exposed portion of the bonding layer 140, that is, the portion of the bonding layer 140 that is not in contact with the source / drain electrodes 150a and 150b, that is, the bonding layer 140 is formed. End portion 140 " a (see Fig. 2D) is oxidized to form an oxidized portion 140a of a material such as TiO2, CrO2, Al2O3, etc. That is, source / drain electrode 150a formed on one surface of bonding layer 140 Since 150b is a metal having a large work function, for example, a noble metal such as gold (Au), platinum (Pt), or the like, the surfaces of the source / drain electrodes 150a and 150b during the oxidation process are used. In this case, the oxidation process hardly occurs, and only the bonding layer end 140 ″ a is oxidized to generate the oxidation portion 140a of the bonding layer 140.

The process of forming the oxidizing portion 140a, that is, the oxidation process of the bonding layer end 140 ″ a may be a thermal oxidation process performed in a furnace under an O 2 atmosphere, as shown in FIG. 2E. For example, it may be carried out by various methods such as plasma oxidation treatment by O2 or O3 plasma, and an appropriate method may be selected according to design specifications such as the material of the substrate and the insulating layer.

In addition, the forming of the oxidation unit 140a is not limited to the order of FIGS. 2A to 2E, and may be performed immediately after the bonding layer 140 is formed, but before the source / drain electrodes 150a and 150b are formed. Although various configurations may be taken, the bonding layer 140 and the source / drain electrode (not to prevent electrical communication between the source / drain electrodes 150a and 150b and the bonding layer 140 may be prevented from being caused by electrical communication between them). It is preferable to perform the oxidation treatment step after the formation of 150a, 150b).

After the oxide layer 140a is formed in the bonding layer 140, as shown in FIG. 2F, the organic semiconductor layer 160 is formed on one surface including the bonding layer 140, and the organic semiconductor layer 160 is a source. / Drain regions 160a and b and channel regions 160c connecting them. In addition, the organic semiconductor layer 160 includes pentacene, tetracene, atracene, naphthalene, alpha-6-thiophene, perylene and its derivatives, rubrene (rubrene) and its derivatives, coronene and its derivatives, perylene tetracarboxylic diimide and its derivatives, perylene tetracarboxylic dianhydride and its derivatives , Polythiophene and its derivatives, polyparaphenylenevinylene and its derivatives, polyparaphenylene and its derivatives, polyfluorene and its derivatives, polythiophenevinylene and its derivatives, polythiophene-heterocyclic aromatic aerial Copolymers and derivatives thereof, oligoacenes and derivatives thereof of naphthalene, oligothiophenes and derivatives thereof of alpha-5-thiophene, phthalocyanine and derivatives thereof, with or without metal, pyromellitic Anhydrides and derivatives thereof, pyromellitic diimides and derivatives thereof, perylenetetracarboxylic acid dianhydrides and derivatives thereof, and perylenetetracarboxylic diimides and derivatives thereof .

On the other hand, the thin film transistor according to the present invention can take a variety of operating configurations depending on the degree of oxidation step, that is, the degree of generation of the oxidation portion. 3A and 3B are enlarged views of the reference numeral “B” of FIG. 2F. The gate insulating layer 130 is formed on one surface of the gate electrode 120, and the bonding layer is formed on one surface of the gate insulating layer 130. 140 and source / drain electrodes 150a and 150b are formed, and one end of the source / drain electrodes 150a and 150b formed on one surface of the bonding layer 140 is in contact with the organic semiconductor layer 160. One end of the bonding layer 140, which is in contact with the organic semiconductor layer 160, is composed of an oxide part 140a.

The oxidizing unit 140a is formed by oxidation of the bonding layer 140 at the end 140 ″ a (see FIG. 2D) during the oxidation process. For example, the oxidizing unit 140a may be formed of a material such as TiO 2, Al 2 O 3, or CrO 2. The oxide group concentration of 140a and b is continuously changed, and the thickness of the oxide portion in the direction from the interface with the organic semiconductor layer 160 toward the bonding layer 140 can also be adjusted. Various operation configurations can be taken by appropriately adjusting the oxide group concentration to thickness of the resin.

For example, as illustrated in FIG. 3A, electrical communication between the source / drain electrodes 150a and 150b may be performed through the channel region of the bonding layer 140 and the organic semiconductor layer 160. This is possible by continuously changing the work function difference between the bonding layer 140 and the organic semiconductor layer 160 with the oxidation portion 140a having an appropriate oxide group concentration and / or thickness.

That is, an accumulation voltage 161a is formed in the organic semiconductor layer 160 in contact with the gate insulating layer 130 by applying an appropriate voltage to the gate electrode 120. The accumulation layer 161a is formed through the source electrode 150a. The obtained electrical signal is passed through the oxidation unit 140a having an appropriate oxide group concentration and / or thickness La, and the drain electrode 150b through charge carriers collected in the storage layer 161a of the channel region of the organic semiconductor layer 160. In this case, electrical communication between the source / drain electrodes 150a and 150b is achieved.

As another example, as illustrated in FIG. 3B, electrical communication between the source / drain electrodes 150a and 150b may be directly performed through the channel region of the organic semiconductor layer 160 without passing through the bonding layer 140.

That is, when the oxidizing portion 140b has a large oxide group concentration and / or thickness (thickness in the direction from the interface with the organic semiconductor layer toward the bonding layer 140; Lb), the oxidizing portion 140b has an insulating layer. When the voltage is applied to the gate electrode 120 to induce charge carriers, the accumulation layer 161b of the channel region of the organic semiconductor layer 160 is in contact with the gate insulating layer 130 and is oxidized. The channel region 160c of the organic semiconductor layer 160 includes a U-shaped channel, that is, a U-shaped accumulation layer 161b by being formed on one surface of the junction 140b. Therefore, in this case, electrical communication between the source / drain electrodes 150a and 150b may be directly performed through the U-shaped accumulation layer 161b therebetween.

Therefore, when the oxide parts 140a and 140b are provided at the end portions of the bonding layer 140 in contact with the organic semiconductor layer 160, the source / regardless of the oxide family concentration and / or the thickness of the oxide parts 140a and 140b. Seamless electrical communication between the drain electrodes 150a and 150b can be achieved.

In addition, the thin film transistor having the above structure may be provided in a flat panel display device such as a liquid crystal display device and / or an organic electroluminescent display device.

FIG. 4 shows an organic electroluminescent display device as an example including the above-described thin film transistor, and shows one subpixel of the organic electroluminescent display device, each of which is provided with an organic electroluminescent device as a self-luminous device. At least one thin film transistor and a capacitor are provided.

The organic electroluminescent display device has various pixel patterns according to the emission color of the organic electroluminescent element, and preferably includes red, green, and blue pixels.

Each of the red (R), green (G), and blue (B) sub-pixels includes an organic electroluminescent element that is a self-luminous element and the above-described thin film transistor, wherein the thin film transistor is not limited to the above examples. At least an end portion in contact with the organic semiconductor layer may have various configurations in a range including a bonding layer composed of an oxidized portion.

As shown in FIG. 4, the gate electrode 220 is formed on one surface of the substrate 210, and a buffer layer 211 may be interposed therebetween. The substrate 210 may be a glass material, or may be a plastic material when flexibility is required, and may have various configurations. Although the gate insulating layer 230 is formed on the gate electrode 220, the gate electrode 220 is covered. A source / drain electrode 250 is formed on one surface of the gate insulating layer 230, and a bonding layer 240 is interposed between the gate insulating layer 230 and the source / drain electrode 250. The organic semiconductor layer 260 is formed on one surface including the source / drain electrode 250, and the portion of the junction layer 240 contacting the organic semiconductor layer 260 may be formed by the oxidation portion as described in the above-described embodiments. 240a.

The organic semiconductor layer 260 includes source / drain regions 260a and b and a channel region 260c.

On one surface of the organic semiconductor layer 260, the lower stacked portion is formed with a protective layer 270 for protecting and / or planarization, the protective layer 270 may be formed of an organic material and / or an inorganic material, a single layer It may take a variety of configurations, such as may be formed of a plurality or a plurality of layers.

An organic EL device 300 is provided on the passivation layer 270. The organic EL device 300 includes a first electrode layer 310, an organic EL device 330, and a second electrode layer 340. Equipped. The first electrode layer 310 is formed on one surface of the passivation layer 270, and the first electrode layer 310 is a via hole 271 formed in the passivation layer 270b of the passivation layer 270 and the organic semiconductor layer 260. The via hole 271 is in electrical communication with the drain electrode 250b of the thin film transistor stacked below. The via hole 271 may be formed separately for each layer, or may be simultaneously formed in some cases.

After the first electrode layer 310 is disposed, a pixel defining layer 320 for defining the pixel opening 321 is formed. The pixel opening 321 has the pixel defining layer 320 so that the first electrode layer 310 is exposed. ) May be formed through proper patterning after the entire surface is formed. After the pixel opening 321 is formed, an organic electroluminescent unit 330 including at least a light emitting layer is formed on one surface of the first electrode layer 310 through the pixel opening 321, and the second electrode layer 340 is formed thereon. It is formed, but is not limited to this may take a variety of configurations. In addition, the first electrode layer 310 may operate as an anode electrode and the second electrode layer 340 may serve as a cathode electrode, and may have opposite polarities.

The first electrode layer 310 may have various configurations. For example, when the first electrode layer 310 operates as an anode electrode and is a bottom emission type, the first electrode layer 310 may be a transparent electrode made of a transparent conductive material such as ITO, IZO, ZnO, or In 2 O 3, or a top emission. Type may be composed of a reflective electrode including Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and a compound thereof, and a transparent electrode formed thereon, and the first electrode layer 310 ) Is not limited to a single layer or a double layer, and may be variously modified, such as being composed of multiple layers.

As the organic electroluminescent unit 330, a low molecular or polymer organic film may be used. When the low molecular organic film is used, a hole injection layer (HIL), a hole transport layer (HTL), and an emission layer (EML) are emitted. ), An electron transport layer (ETL), an electron injection layer (EIL), or the like, may be formed by stacking a single or a complex structure, and the usable organic material may be copper phthalocyanine (CuPc). , N, N-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl-benzidine: NPB), Various applications are possible, including tris-8-hydroxyquinoline aluminum (Alq3). These low molecular weight organic films are formed by the vacuum deposition method.

In the case of the polymer organic film, the structure may include a hole transporting layer (HTL) and a light emitting layer (EML). In this case, PEDOT is used as the hole transporting layer, and polyvinylvinylene (PPV) and polyfluorene are used as the light emitting layer. Polymer organic materials such as (Polyfluorene) are used and can be formed by screen printing or inkjet printing. The organic layers constituting the organic electroluminescent unit are not necessarily limited thereto, and various embodiments may be applied.

Similarly, in the case of the first electrode layer 310, the second electrode layer 340 may have various configurations depending on the polarity and the light emission type of the electrode layer. That is, when the second electrode layer 340 acts as a cathode and the light emission type is a bottom emission type, the second electrode layer 340 is Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, and their A material having a small work function and reflecting function, such as a compound, may be composed of one or more layers, and in the case of a top emission type, Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, and compounds thereof After forming an electrode for matching the work function on one surface of the organic electroluminescent unit 330, a variety of configurations may be taken, such as forming a transparent electrode such as ITO, IZO, ZnO, In2O3.

The above embodiments are examples for describing the present invention, and the present invention is not limited thereto, and the thin film transistor according to the present invention may be formed in various ways in which at least a portion in contact with the organic semiconductor layer includes a bonding layer composed of an oxide part. Modifications are possible. That is, when the organic semiconductor layer of the thin film transistor is composed of n-type, it may be configured to further include a magnetic assembly to reduce the work function difference with the source / drain electrode, the thin film transistor is an organic electroluminescent display device In addition, various modifications may be considered, such as applicable to a liquid crystal display device, and mounted on a driver circuit in which an image is not implemented in addition to the flat panel display device.

According to the present invention as described above, the following effects can be provided.

First, the bonding layer is interposed between the source / drain electrode and the gate insulating layer, and the oxide layer is provided on the bonding layer in contact with the organic semiconductor layer, thereby securing the bonding property between the source / drain electrode and the gate insulating layer, and at the same time, the organic semiconductor layer. A thin film transistor may be provided in which electrical communication between the source / drain electrodes may be smoothly performed.

Secondly, the flat panel display device according to the present invention includes the above-described thin film transistor, so that smooth signal processing can be performed in a circuit unit such as a driver and the like, and an electric signal transmitted to a pixel (subpixel) can be appropriately transferred. It is also possible to provide a flat panel display device having excellent screen quality and reducing power consumption by preventing brightness degradation.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Could be. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (8)

Board; A gate electrode formed on the substrate; A gate insulating layer formed on the gate electrode; A source / drain electrode formed on the gate insulating layer to be insulated from the gate electrode; And And an organic semiconductor layer in contact with the source / drain electrode and insulated from the gate electrode.  A junction layer is interposed between the gate insulating layer and the source / drain electrode, and a work function of the junction layer is smaller than a work function of the source / drain electrode, and at least a portion of the junction layer in contact with the organic semiconductor layer is A thin film transistor, characterized in that the oxidation treatment is oxidized. The method of claim 1, The source / drain electrode is selected from the group consisting of gold (Au), palladium (Pd), platinum (Pt), nickel (Ni), rhodium (Rh), ruthenium (Ru), iridium (Ir), and osmium (Os). A thin film transistor comprising at least one. The method of claim 1, The junction layer includes at least one selected from the group consisting of titanium (Ti), chromium (Cr), aluminum (Al), and molybdenum (Mo). The method of claim 1, The organic semiconductor layer may include pentacene, tetracene, atracene, naphthalene, alpha-6-thiophene, perylene and derivatives thereof, rubrene And derivatives thereof, coronene and derivatives thereof, perylene tetracarboxylic diimide and derivatives thereof, perylene tetracarboxylic dianhydride and derivatives thereof, polyti Offen and its derivatives, polyparaphenylenevinylene and its derivatives, polyparaphenylene and its derivatives, polyfluorene and its derivatives, polythiophenevinylene and its derivatives, polythiophene-heterocyclic aromatic copolymers and their Derivatives, oligoacenes and derivatives thereof of naphthalene, oligothiophenes and derivatives thereof of alpha-5-thiophene, phthalocyanine and derivatives thereof with or without metal, pyromellitic dian Ilide and its derivatives, pyromellitic diimide and derivatives thereof, perylenetetracarboxylic acid dianhydride and derivatives thereof and perylenetetracarboxylic diimide and derivatives thereof Thin film transistor. A flat panel display device comprising the thin film transistor according to any one of claims 1 to 4 and comprising at least one pixel. The method of claim 5, And the pixel includes a first electrode layer, a second electrode layer, and an organic electroluminescent part interposed therebetween. A gate electrode formed on the substrate; Providing a gate insulating layer formed on the gate electrode; Forming a bonding layer on one surface of the gate insulating layer; Forming a source / drain electrode on one surface of the bonding layer; Forming an organic semiconductor layer in contact with said source / drain electrode, And oxidizing at least a portion of the junction layer in contact with the organic semiconductor layer before forming the organic semiconductor layer. The method of claim 7, wherein And the oxidation treatment step is performed after the source / drain electrode forming step and before the organic semiconductor layer forming step.

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