KR101435474B1 - Array Substrate of Organic Thin Film Transistor Liquid Crystal Display Device and Method of Fabricating the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and more particularly, to an array substrate for an organic thin film transistor liquid crystal display device capable of improving driving characteristics in an organic thin film transistor using a polymer material as a semiconductor layer and a method of manufacturing the same.

An organic thin film transistor liquid crystal display device according to the present invention includes a substrate divided into a switching region, a pixel region, a gate region, and a data region; A data line arranged in one direction of a data region on the substrate; a source electrode extending in the data line; a drain electrode spaced apart from the source electrode; A metal oxide film pattern formed on the exposed upper surface of the data wiring, the source and drain electrodes; A pixel electrode directly in side contact with the drain electrode; An organic semiconductor layer located on the overlapped top of the source and drain electrodes; A gate insulating film pattern covering the organic semiconductor layer and the gate region; A gate electrode located above the gate insulating film pattern and corresponding to the gate region; a gate electrode protruded from the gate wiring; And a protective film covering the gate electrode and the wiring, the data wiring and the organic semiconductor layer, and including a pixel open hole exposing the pixel region.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array substrate for an organic thin film transistor liquid crystal display device,

The present invention relates to a liquid crystal display device, and more particularly, to an array substrate for an organic thin film transistor liquid crystal display device capable of improving driving characteristics in an organic thin film transistor using a polymer material as a semiconductor layer and a method of manufacturing the same.

In recent years, in response to the development of the information society, demands for display devices have been increasing in various forms. Recently, in response to this demand, a liquid crystal display device (LCD), a plasma display panel (PDP), a vacuum fluorescent display (VFD) Display) have been studied, and some of them have already been used as display devices in various devices.

Among them, liquid crystal display devices are mostly used while substituting CRT (Cathode Ray Tube) for the purpose of a portable image display device because of their excellent image quality, light weight, thinness and low power consumption. A monitor for receiving and displaying a broadcast signal, a monitor for a computer, and the like.

BACKGROUND ART [0002] Recent researches on techniques utilizing an organic semiconductor as an active layer among thin film transistors of a liquid crystal display device have been actively conducted.

Typically, organic semiconductors have been developed by the development of polyacetylene, a conjugated organic polymer that exhibits semiconducting properties, and then, due to the nature of organic materials such as various synthetic methods, ease in film form, flexibility, Functional electronic devices and optical devices as materials.

Among devices using such a conductive polymer, researches on an organic thin film transistor (OTFT) using an organic material as an active layer have been extensively studied. The OTFT is structurally similar to the Si-TFT in that organic material is used instead of Si in the semiconductor region.

Hereinafter, a conventional organic thin film transistor liquid crystal display device and a manufacturing method thereof will be described with reference to the accompanying drawings.

1 is a plan view showing a unit pixel of an array substrate for an organic thin film transistor liquid crystal display according to a related art.

As shown, a gate wiring 20 and a data wiring 30 which define a pixel region P in a vertical crossing on the substrate 10 are constituted. At the intersection of the gate line 20 and the data line 30, an organic thin film transistor OT serving as a switching is formed.

The organic thin film transistor OT includes a gate electrode 25 extending from the gate wiring 20, an organic semiconductor layer 40 partially overlapping the gate electrode 25, And includes a source electrode 32 and a drain electrode 34 spaced apart from the source electrode 32.

And the pixel electrode 70 directly contacting the drain electrode 34 is configured to correspond to the pixel region P. [

Hereinafter, a conventional organic thin film transistor will be described in more detail with reference to the accompanying drawings.

2A and 2B are cross-sectional views taken along the line II-II 'in FIG. 1, and more specifically, four schemes according to positions where gate electrodes, organic semiconductor layers, source and drain electrodes are formed .

These four schemes include a bottom gate / top contact structure (i), a bottom gate / bottom contact structure (ii), a top gate / bottom contact structure (iii), and a top gate / top contact structure (iv).

2A shows a bottom gate method in which the gate electrode 25 is located at the bottom. A gate insulating film pattern 45, an organic semiconductor layer 40, a source and a drain are formed on the gate electrode 25, Drain electrodes 32 and 34 are sequentially disposed on the gate electrode 25. A gate insulating film pattern 45, source and drain electrodes 32 and 34, And the bottom contact structure (ii) in which the semiconductor layer 40 is sequentially positioned.

The source and drain electrodes 32 and 34, the organic semiconductor layer 40, and the gate insulating film pattern 45 are formed on the left side of FIG. 2B. FIG. 2B shows a top gate method in which the gate electrode 25 is located at the top. Source and drain electrodes 32 and 34, a gate insulating film pattern 45, and a gate electrode (not shown) on the right side of the bottom contact structure iii. 25 in this order.

The gate electrode 25, the gate insulating film pattern 45, the organic semiconductor layer 40, and the source and drain electrodes 32 and 34 form the organic thin film transistor OT.

Such an organic thin film transistor (OT) is advantageous in that it can be manufactured at a low temperature process of 200 ° C or less and can be formed on a plastic substrate having less heat resistance and chemical resistance than glass.

Particularly, even if a metal material and an insulating material which form each electrode and wiring are formed through a low-temperature deposition or coating method at a low-temperature process of 200 ° C or less, the characteristics of the organic thin film transistor (OT) Temperature process using amorphous silicon (a-Si: H) as the semiconductor layer 40, the endurance structure is not dense, and thus important characteristics such as electrical conductivity may be deteriorated.

Therefore, in order to overcome this problem, the organic semiconductor layer 40 is formed using an organic material such as pentacene having a semiconductor property instead of a conventional semiconductor material such as amorphous silicon.

The HOMO energy level of a material such as pentacene is similar to the MOMO energy level of gold (Au), and thus has a superior contact resistance with pentacene as compared with other metal materials. Researches for forming the drain electrodes 32 and 34 have been actively conducted.

However, since gold has a high price of the material, it is not only limited in mass application, but even if gold is deposited through a sputtering process, an acid-based etchant containing nitric acid, phosphoric acid, hydrochloric acid, , It is replaced with an etching solution which is a mixture of iodine and water. However, since iodine is highly toxic, there is a concern that it may cause environmental pollution.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems described above, and it is an object of the present invention to improve the driving characteristics of an organic thin film transistor by replacing a material having an excellent contact property with an organic semiconductor layer and a material similar to gold's electric conductivity to source and drain electrodes .

According to another aspect of the present invention, there is provided a method of fabricating an array substrate for an organic thin film transistor liquid crystal display, including: defining a switching region, a pixel region, a gate region, and a data region on a substrate; Forming source and drain metal layers on the substrate; Performing an O ₂ plasma treatment on the source and drain metal layers to form a metal oxide film; A source electrode extending in the data line, a drain electrode spaced apart from the source electrode, and a drain electrode spaced apart from the source electrode, wherein the drain electrode and the metal oxide film are formed by patterning the source and drain metal layers and the metal oxide film collectively, Forming a metal oxide film pattern corresponding to an upper surface of the wiring, source and drain electrodes; Forming a pixel electrode directly in side contact with the drain electrode; Forming an organic semiconductor layer on the source and drain electrodes; Forming a gate insulating film pattern covering the organic semiconductor layer and the gate region; Forming a gate wiring corresponding to the gate region and a gate electrode protruding from the gate wiring on the gate insulating film pattern; And forming a pixel open hole that covers the gate wiring and the upper portion of the gate electrode and exposes the pixel electrode corresponding to the pixel region.

delete

delete

delete

delete

At this time, the source and drain metal layers are formed of a selected one of conductive material groups including molybdenum, silver, and copper. Wherein the metal oxide film is any one selected from the group consisting of molybdenum oxide, silver oxide, and copper oxide.

The metal oxide layer is formed to a thickness ranging from 50 to 500 angstroms.

According to another aspect of the present invention, there is provided a method of fabricating an array substrate for an organic thin film transistor liquid crystal display, including: defining a switching region, a pixel region, a gate region, and a data region on a substrate; Forming a gate wiring in a direction corresponding to the gate region and a gate electrode protruding from the gate wiring; Forming a gate insulating film pattern covering the gate wiring and an upper portion of the gate electrode; Forming source and drain metal layers on the gate insulating film pattern; Performing an O ₂ plasma treatment on the source and drain metal layers to form a metal oxide layer; A source electrode extending in the data line, a drain electrode spaced apart from the source electrode, and a drain electrode spaced apart from the source electrode, wherein the source and drain metal layers and the metal oxide film are collectively patterned, Forming a metal oxide film pattern corresponding to an upper surface of the data line, the source and drain electrodes; Forming a pixel electrode directly in side-contact with the drain electrode; Forming an organic semiconductor layer on the overlapped top of the source and drain electrodes; Forming a passivation layer covering the data line, the source and drain electrodes, and the organic semiconductor layer and including a pixel open hole exposing the pixel electrode.

In the present invention, first, a metal material including molybdenum, silver, and copper is used as a source and a drain electrode of an organic thin film transistor, and a metal oxide film is formed on the source and drain electrodes by a plasma treatment, Can be improved.

Second, the production yield can be improved by applying molybdenum, silver, and copper, which are less expensive than gold and which are well reacted with acid-based etchants including hydrofluoric acid, nitric acid, and phosphoric acid.

--- Example 1 ---

The invention is price and less expensive than gold, O ₂ interface contact resistance with the use of small molybdenum than the gold source and drain electrodes a top-gate / bottom-contact structure in with the organic semiconductor layer through a plasma treatment OTFT Thereby improving the driving characteristics of the driving circuit.

Hereinafter, an organic thin film transistor liquid crystal display device according to the present invention will be described with reference to the accompanying drawings.

FIG. 3 is a plan view showing a unit pixel of an array substrate for an organic thin film transistor liquid crystal display according to a first embodiment of the present invention, and FIG. 4 is a sectional view taken along the line IV-IV ' / Top contact structure is shown as an example.

3 and 4, the data line 130, the source electrode 132 extending from the data line 130, and the source electrode 132 are spaced apart from each other in one direction on the substrate 110, Drain electrode 134 is formed.

A metal oxide film pattern 150 is formed on the data line 130, the source and drain electrodes 132 and 134, The metal oxide film pattern 150 is formed on the exposed surfaces of the source and drain electrodes 132 and 134 to have a very thin thickness of about 50 to 500 Å through an O ₂ plasma. The metal oxide film pattern 150 may be formed of any one selected from molybdenum oxide (MoO ₃ ), silver oxide (AgO ₃ ), and copper oxide (CuO ₃ ) based on molybdenum (Mo), silver (Ag) Can be applied.

And the pixel electrode 170 directly contacting the drain electrode 134 is formed to correspond to the pixel region P. [ The pixel electrode 170 is formed of one selected from a group of transparent conductive materials including indium-tin-oxide (ITO) and indium-zinc-oxide (IZO).

The organic semiconductor layer 140 is formed of a selected one of organic semiconductor materials including pentacene and polythiophene between the source electrode 132 and the drain electrode 134. The organic semiconductor layer 140 is formed in an island-shaped pattern superimposed on a portion of each of the source electrode 132 and the drain electrode 134.

A gate insulating layer pattern 145 is formed on the organic semiconductor layer 140 and a gate wiring 120 is formed on the organic insulating layer 140 to define a pixel region P perpendicular to the data wiring 130. And the protruding gate electrode 125 are stacked in this order.

A top gate / bottom contact organic thin film transistor (TFT) transistor including the source and drain electrodes 132 and 134, the metal oxide film pattern 150, the organic semiconductor layer 140, the gate insulating film pattern 145, (OT).

A passivation layer 155 including a pixel opening hole (POH) exposing the pixel electrode 170 corresponding to the pixel region PA is formed on the gate electrode 125. The pixel open hole (POH) functions to improve the transmittance of the pixel electrode (170).

The pixel electrode 170 is designed so as to overlap with the gate line 120 at the previous stage and the gate line 120 at the previous stage serves as a first electrode and the pixel electrode 170 overlapped with the first electrode is used as a second electrode And a storage capacitor Cst having a gate insulating film pattern 145 interposed between the first and second electrodes as a dielectric layer is formed.

The metal oxide film pattern 150 has a structure in which the source and drain electrodes 132 and 134 and the organic semiconductor layer 140 are interposed between the source and drain electrodes 132 and 134, 134, and the organic semiconductor layer 140. The organic semiconductor layer 140 may be formed of a metal such as silicon oxide. Therefore, driving characteristics of the organic thin film transistor OT can be improved.

Hereinafter, a method of manufacturing an array substrate for an organic thin film transistor liquid crystal display according to the present invention will be described in more detail.

FIGS. 5A to 5F are sectional views of the process shown in FIG. 3 along the line IV-IV 'in FIG.

A step of defining a switching region SA, a pixel region PA, a gate region GA and a data region DA is performed on the substrate 110 as shown in Fig. 5A. At this time, the substrate 110 may be made of glass or plastic.

A source and drain metal layer (not shown) is formed on the substrate 110 on which the plurality of regions SA, PA, GA, and DA are defined, with a selected one of a group of conductive materials including molybdenum (Mo), silver (Ag) 175 are formed.

Next, an O ₂ plasma process is performed on the entire upper surface of the substrate 110 on which the source and drain metal layers 175 are formed.

As shown in FIG. 5B, the metal oxide layer 150a is formed on the exposed surface of the source and drain metal layers 175 through the above-described O ₂ plasma treatment. The metal oxide film (150a) is a molybdenum (Mo), silver (Ag), copper any one selected from (Cu) and ₍₃ MoO), a molybdenum oxide oxidation reaction may be an oxide (AgO _3), copper oxide (CuO ₃₎ the Can be used.

The metal oxide layer 150a functions to improve interfacial contact characteristics with the organic semiconductor layer (140 in Fig. 3) to be formed in a subsequent process.

In general, the source and drain metal layers 175 are formed to a thickness of 2000 to 3000 ANGSTROM. If the thickness of the metal oxide layer 150a is set to a very small thickness as described above, the metal oxide layer 150a formed to have a thickness of 500 ANGSTROM or more may exhibit non-conductive characteristics, and hole injection may become difficult. Thus, the metal oxide layer 150a is formed on the exposed upper surface of the source and drain metal layers 175 to a very thin thickness, preferably in the range of 50 to 500 angstroms.

Although not shown in detail in the drawings, it is possible to form a natural oxide film (not shown) by allowing the metal material such as molybdenum, silver and copper to easily oxidize in the atmosphere, There is a problem that the reliability is lowered compared with the O ₂ plasma treatment because there is a limit to the uniformity of the thickness.

As an alternative to this, a method of forming the metal oxide layer 150a by heat-treating the source and drain metal layers 175 in an oven (not shown) for a long time may be applied instead of the O ₂ plasma treatment.

The source and drain metal layers (175 in FIG. 5B) and the metal oxide layer (150a in FIG. 5B) are collectively patterned to form the data lines DA in one direction corresponding to the data area DA, A source electrode 132 extending from the data line 130 and a drain electrode 134 spaced apart from the source electrode 132 are formed. A plurality of metal oxide film patterns 150 are formed on the exposed upper surfaces of the data line 130 and the source and drain electrodes 132 and 134, respectively.

Next, indium-tin-oxide (ITO) and indium-zinc-oxide (ITO) are deposited on the entire upper surface of the substrate 110 on which the data line 130, the source and drain electrodes 132 and 134 and the metal oxide film pattern 150 are formed. A pixel electrode 170 directly contacting the drain electrode 134 is formed to correspond to the pixel region PA by forming a transparent metal layer (not shown) with a selected one of the transparent conductive material groups including the IZO do. At this time, the pixel electrode 170 is designed to extend to the gate region GA located at the previous stage.

5D, on the entire surface of the substrate 110 on which the data line 130, the source and drain electrodes 132 and 134, the metal oxide film pattern 150 and the pixel electrode 170 are formed, an organic semiconductor material layer (not shown) is formed with a selected one of a group of organic semiconductors including pentacene and polythiophene, and the organic semiconductor material layer is patterned to form an upper portion overlapping the source and drain electrodes 132 and 134 The organic semiconductor layer 140 is formed.

The organic semiconductor layer 140 may be formed using a selected one of an ink jet apparatus, a nozzle coating apparatus, a bar coating apparatus, a slit coating apparatus, and a spin coating apparatus, ≪ / RTI >

5E, an inorganic insulating material group including silicon oxide (SiO ₂ ) and silicon nitride (SiNx) or a photo-acryl group is formed on the entire upper surface of the substrate 110 on which the organic semiconductor layer 140 is formed. And a gate insulating layer pattern (not shown) covering the organic semiconductor layer 140 and the gate region GA is formed by patterning a gate insulating layer (not shown) with a selected one of organic insulating material groups including benzocyclobutene and benzocyclobutene 145 are formed. At this time, when the gate insulating layer is formed of the inorganic insulating material, it is preferable that the gate insulating layer is formed by a low-temperature deposition process so that the organic semiconductor layer 140 is not damaged.

Next, a conductive metal material group including copper (Cu), molybdenum (Mo), aluminum (Al), and aluminum alloy (AlNd) is formed on the entire upper surface of the substrate 110 on which the gate insulating layer pattern 145 is formed. A gate line 120 is formed in one direction corresponding to the gate region GA and a gate line 120 extending from the gate line 120 and overlapped with the organic semiconductor layer 140. [ Thereby forming a gate electrode 125 corresponding to the upper portion. A gate insulating layer pattern 145 is interposed under the organic semiconductor layer 140, the gate line 120, and the gate electrode 125.

At this time, the pixel electrode 170 designed to extend to the gate region GA of the front end is used as the first electrode, the gate wiring 120 of the front end overlapped with the first electrode is used as the second electrode, A storage capacitor Cst having a gate insulating film pattern 145 interposed between the second electrodes as a dielectric layer is formed.

The organic thin film transistor OT includes the source and drain electrodes 132 and 134, the metal oxide film pattern 150, the organic semiconductor layer 140, and the gate electrode 125 and serves as a switching device for the liquid crystal display.

For example, in the source and drain electrodes 132 and 134 formed of molybdenum (Mo), the work function of molybdenum (Mo) itself is 4.6 eV and the work function of gold (Au) is 5.1 eV . The molybdenum (Mo) work function (4.6eV), but not exactly the same as the HOMO energy level of the organic semiconductor layer 140 than the work function (5.1eV) of gold (Au), an oxide of molybdenum, an oxide of self (MoO ₃ ) Has a work function of 5.3 eV, which is advantageous in further lowering the hole injection barrier.

The HOMO (Highest Occupied Molecular Orbital) energy level refers to the molecular orbital of the highest energy level with electrons, and the LUMO (Lowest Unoccupied Molecular Orbital) energy level refers to the molecular orbital of the highest energy level without electrons.

FIG. 6 shows the HOMO energy level and the LOMO energy level of the organic semiconductor layer and the work functions of gold (Au), molybdenum (Mo) and molybdenum oxide (MoO ₃ ), respectively.

5E and 6, the work function (5.1 eV) of gold (Au) and the work function (4.6 eV) of molybdenum (Mo) are set so that the HOMO energy level of the organic semiconductor layer 140 (5.0 eV) An energy barrier exists in injecting holes and this barrier is a contact resistance between the source and drain electrodes 132 and 134 made of gold (Au) or molybdenum (Mo) and the organic semiconductor layer 140 Which causes a problem of hindering the driving characteristics of the organic thin film transistor OT.

Here, the work function of the gold (Au) is located above the HOMO energy level of the organic semiconductor layer 140 because the HUMO energy level of the organic semiconductor layer 140 moves up and down with a deviation of about 2eV And is located mainly below the work function of gold (Au).

However, as in the present invention, when the source and drain electrodes 132 and 134 are formed using molybdenum (Mo) and O ₂ plasma treatment is performed to form a very thin molybdenum oxide (MoO ₃ ), molybdenum Since the work function (5.3 eV) of the oxide (MoO ₃ ) is formed at a position lower than the HOMO energy level of the organic semiconductor layer 140, the energy barrier does not exist in the hole injection.

Therefore, in the first embodiment of the present invention, the metal oxide film pattern 150 is interposed between the source and drain electrodes 132 and 134 and the organic semiconductor layer 140, There is an advantage that the flow of the electrons moving to the inside can be controlled smoothly.

That is, the molybdenum oxide (MoO ₃ ) serves to control the contact resistance between the organic semiconductor layer 140 and the source and drain electrodes 132 and 134, so that the source and drain electrodes 132 and 134, Molybdenum oxide (MoO ₃ ) located at the contact interface between the semiconductor layers 140 functions to improve the charge mobility in the channel (ch) when the drive voltage is applied.

Therefore, the use of a conductive material including molybdenum (Mo), silver (Ag), copper (Cu) or the like which is considerably inexpensive compared with gold (Au) and the addition of an O ₂ plasma treatment process to such molybdenum It is possible to improve driving characteristics of the organic thin film transistor OT without difficulty in the process.

An inorganic insulating material group including silicon oxide and silicon nitride or an organic insulating material group including benzocyclobutene and photoacrylic is formed on the entire surface of the substrate 110 on which the gate electrode 125 and the gate wiring 120 are formed as shown in FIG. A protective film 155 is formed with a selected one of organic insulating material groups.

Next, a passivation layer 155 corresponding to the pixel region PA is patterned to form a pixel opening hole (POH) exposing the pixel electrode 170. The pixel open hole POH serves to improve the transmittance of the pixel electrode 170.

Thus, an array substrate for an organic thin film transistor liquid crystal display device according to the present invention can be manufactured.

In summary, in the first embodiment of the present invention, molybdenum, silver, copper, or the like, whose contact resistance at the interface with the organic semiconductor layer is lower than gold through O ₂ plasma treatment, And the drain electrode, driving characteristics of the top gate / bottom contact organic thin film transistor can be improved.

FIGS. 7A and 7B are graphs illustrating the driving characteristics of the organic thin film transistor according to the first embodiment of the present invention, and will be described in more detail with reference to FIG.

7A shows a resistance value according to a gate voltage. More specifically, a contact surface 1 between gold and an organic semiconductor layer, a contact surface 2 between molybdenum and an organic semiconductor layer, a molybdenum oxide and an organic semiconductor layer 3, And the contact resistance between the contact surface and the contact surface.

At this time, in the case of (2) and (3), it is confirmed that the contact resistance according to the gate voltage is significantly lower than (1).

FIG. 7B is a graph showing I-V characteristics. More specifically, FIG. 7B shows experimental results when source and drain electrodes are formed of gold (1) and molybdenum (2), respectively.

At this time, the drain / source current value according to the gate / source voltage is shown. It can be seen that when the molybdenum (2) is used in comparison with the gold (1), the drain / source current value according to the gate / source voltage remarkably increases.

Therefore, as in the first embodiment of the present invention, the driving characteristics of the thin film transistor can be improved by forming source and drain electrodes using materials such as molybdenum, silver, and copper, There are advantages.

--- Example 2 ---

A second embodiment of the present invention is characterized by applying a bottom gate / bottom contact structure.

The second embodiment of the present invention is the same as the first embodiment in its purpose and effect, and only the structure thereof will be briefly described.

FIG. 8 is a plan view showing a unit pixel of an array substrate for an organic thin film transistor liquid crystal display according to a second embodiment of the present invention, and FIG. 9 is a cross-sectional view taken along line IX- / Bottom contact structure.

8 and 9, a gate wiring 220 and a gate electrode 225 extending from the gate wiring 220 are formed on a substrate 210 in one direction.

Thereby forming a gate insulating film pattern 145 covering the gate wiring 220 and the upper portion of the gate electrode 225. A data line 230 defining a pixel region PA perpendicularly intersecting the gate line 220 and a source electrode 232 extending from the data line 230, And a drain electrode 234 spaced apart from the electrode 232.

A metal oxide film pattern 150 is formed on the data line 230, the source and drain electrodes 232 and 234, respectively. The metal oxide film pattern 250 is formed on the exposed surfaces of the source and drain electrodes 232 and 234 to have a very thin thickness of about 50 to 500 Å through an O ₂ plasma. The metal oxide film pattern 250 may be formed of any one selected from molybdenum oxide (MoO ₃ ), silver oxide (AgO ₃ ), and copper oxide (CuO ₃ ) based on molybdenum (Mo), silver (Ag) One can be applied.

The pixel electrode 270 directly contacting the drain electrode 234 is configured to correspond to the pixel region P. [ The pixel electrode 270 is formed of one selected from the group of transparent conductive materials including indium-tin-oxide (ITO) and indium-zinc-oxide (IZO).

An organic semiconductor layer 240 is formed of a selected one of organic semiconductor materials including pentacene and polythiophene between the upper and lower portions of the source and drain electrodes 232 and 234. The organic semiconductor layer 240 is composed of an island-shaped pattern superimposed on a portion of each of the source electrode 232 and the drain electrode 234.

The organic thin film transistor of the bottom gate / bottom contact structure including the gate electrode 225, the gate insulating film pattern 245, the source and drain electrodes 232 and 234, the metal oxide film pattern 250, (OT).

A passivation layer 255 including a pixel open hole (POH) exposing the pixel electrode 270 corresponding to the pixel region PA is formed on the organic thin film transistor OT. The pixel open hole (POH) functions to improve the transmittance of the pixel electrode (270).

The pixel electrode 270 is extended so as to overlap with the gate wiring 220 at the previous stage and the gate wiring 220 at the previous stage is used as a first electrode and the pixel electrode 270 overlapped with the first electrode And a storage capacitor Cst having a gate insulating film pattern 245 interposed between the first and second electrodes as a dielectric layer is formed.

Therefore, the second embodiment of the present invention is expected to have the same effect as the first embodiment, except that the second embodiment is different from the first embodiment only in its configuration. The manufacturing method of the second embodiment of the present invention is not greatly different from the manufacturing method of the first embodiment, and a description thereof will be omitted.

As described so far, it can be inferred that the present invention can be applied to any structure in which the semiconductor layer is located above the source and drain electrodes. The present invention is not limited to the first and second embodiments, It will be obvious that various changes and modifications may be made without departing from the spirit and scope of the invention.

1 is a plan view showing a unit pixel of an array substrate for a conventional organic thin film transistor liquid crystal display device according to the related art.

2A and 2B are cross-sectional views taken along the line II-II 'in FIG.

3 is a plan view showing a unit pixel of an array substrate for an organic thin film transistor liquid crystal display according to a first embodiment of the present invention.

4 is a cross-sectional view taken along line IV-IV 'of FIG. 3;

FIGS. 5A to 5F are cross-sectional views of the process, taken along the line IV-IV 'of FIG.

6 is a diagram showing the HOMO energy level and the LOMO energy level of the organic semiconductor layer, and the work function of gold, molybdenum, and molybdenum oxide, respectively.

FIGS. 7A and 7B are graphs showing experimental results of driving characteristics of the organic thin film transistor according to the first embodiment of the present invention. FIG.

8 is a plan view showing a unit pixel of an array substrate for an organic thin film transistor liquid crystal display according to a second embodiment of the present invention.

9 is a cross-sectional view taken along line IX-IX 'of Fig.

Description of the Related Art [0002]

110: substrate 120: gate wiring

125: gate electrode 130: data wiring

132: source electrode 134: drain electrode

140: organic semiconductor layer 145: gate insulating film pattern

150: metal oxide film pattern 155: protective film

170: pixel electrode POH: pixel open hole

Cst: Storage Capacitor

Claims (10)

delete delete delete delete delete Defining a switching region, a pixel region, a gate region, and a data region on a substrate; Forming source and drain metal layers on the substrate; Performing an O ₂ plasma treatment on the source and drain metal layers to form a metal oxide film; A source electrode extending in the data line, a drain electrode spaced apart from the source electrode, and a drain electrode spaced apart from the source electrode, wherein the drain electrode and the metal oxide film are formed by patterning the source and drain metal layers and the metal oxide film collectively, Forming a metal oxide film pattern corresponding to an upper surface of the wiring, source and drain electrodes; Forming a pixel electrode directly in side contact with the drain electrode; Forming an organic semiconductor layer on the source and drain electrodes; Forming a gate insulating film pattern covering the organic semiconductor layer and the gate region; Forming a gate wiring corresponding to the gate region and a gate electrode protruding from the gate wiring on the gate insulating film pattern; Forming a pixel open hole that covers an upper portion of the gate line and the gate electrode and exposes a pixel electrode corresponding to the pixel region, The method of manufacturing an array substrate for an organic thin film transistor liquid crystal display device according to claim 1, The method according to claim 6, Wherein the source and drain metal layers are formed of one selected from a group of conductive materials including molybdenum, silver, and copper. The method according to claim 6, Wherein the metal oxide film is one selected from the group consisting of molybdenum oxide, silver oxide, and copper oxide. The method according to claim 6, Wherein the metal oxide layer is formed to a thickness ranging from 50 to 500 ANGSTROM. Defining a switching region, a pixel region, a gate region, and a data region on a substrate; Forming a gate wiring in a direction corresponding to the gate region and a gate electrode protruding from the gate wiring; Forming a gate insulating film pattern covering the gate wiring and an upper portion of the gate electrode; Forming source and drain metal layers on the gate insulating film pattern; Performing an O ₂ plasma treatment on the source and drain metal layers to form a metal oxide layer; A source electrode extending in the data line, a drain electrode spaced apart from the source electrode, and a drain electrode spaced apart from the source electrode, wherein the drain electrode and the metal oxide film are formed by patterning the source and drain metal layers and the metal oxide film collectively, Forming a metal oxide film pattern corresponding to an upper surface of the wiring, source and drain electrodes; Forming a pixel electrode directly in side-contact with the drain electrode; Forming an organic semiconductor layer on the overlapped top of the source and drain electrodes; Forming a passivation layer covering the data line, source and drain electrodes and the organic semiconductor layer and including a pixel open hole exposing the pixel electrode, The method of manufacturing an array substrate for an organic thin film transistor liquid crystal display device according to claim 1,

Images