KR20110071641A - Method of fabricating oxide thin film transistor - Google Patents

Abstract

PURPOSE: A method of fabricating an oxide thin film transistor is provided to secure reliable device characteristics by forming an etch stopper through a simple process without the spreading of a back channel region to a conductive material. CONSTITUTION: In a method of fabricating an oxide thin film transistor, a gate electrode(121) is formed on a substrate(110). A gate insulating layer(115a) is formed on the substrate in which the gate electrode is formed. An active layer(124) comprised of an oxide semiconductor is formed on the gate insulating layer. A source electrode(122) and a drain electrode(123) are formed on the channel region of the active layer. An etch stopper(125) is formed between a source electrode and a drain electrode.

Description

Manufacturing Method of Oxide Thin Film Transistor {METHOD OF FABRICATING OXIDE THIN FILM TRANSISTOR}

The present invention relates to a method for manufacturing an oxide thin film transistor, and more particularly, in the combination of AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr; x, y, z> 0). The present invention relates to a method for manufacturing an oxide thin film transistor using an integrative quarter- or tetracomponent oxide semiconductor as an active layer.

Recently, with increasing interest in information display and increasing demand for using a portable information carrier, a lightweight flat panel display (FPD), which replaces a conventional display device, a cathode ray tube (CRT), is used. The research and commercialization of Korea is focused on. In particular, the liquid crystal display (LCD) of the flat panel display device is an image representing the image using the optical anisotropy of the liquid crystal, is excellent in resolution, color display and image quality, and is actively applied to notebooks or desktop monitors have.

The liquid crystal display is largely composed of a color filter substrate and an array substrate, and a liquid crystal layer formed between the color filter substrate and the array substrate.

The active matrix (AM) method, which is a driving method mainly used in the liquid crystal display device, uses an amorphous silicon thin film transistor (a-Si TFT) as a switching device to drive the liquid crystal in the pixel portion. to be.

Hereinafter, a structure of a general liquid crystal display device will be described in detail with reference to FIG. 1.

1 is an exploded perspective view schematically illustrating a general liquid crystal display.

As shown in the figure, the liquid crystal display device is largely a liquid crystal layer (liquid crystal layer) formed between the color filter substrate 5 and the array substrate 10 and the color filter substrate 5 and the array substrate 10 ( 30).

The color filter substrate 5 includes a color filter C composed of a plurality of sub-color filters 7 for implementing colors of red (R), green (G), and blue (B); A black matrix 6 that separates the sub-color filters 7 and blocks light passing through the liquid crystal layer 30, and a transparent common electrode that applies a voltage to the liquid crystal layer 30. 8)

In addition, the array substrate 10 may be arranged vertically and horizontally to define a plurality of gate lines 16 and data lines 17 defining a plurality of pixel regions P. The thin film transistor T, which is a switching element formed in the cross region, and the pixel electrode 18 formed on the pixel region P, are formed.

The color filter substrate 5 and the array substrate 10 are joined to face each other by a sealant (not shown) formed on the outer side of the image display area to form a liquid crystal display panel, and the color filter substrate 5 And the bonding of the array substrate 10 is made through a bonding key (not shown) formed in the color filter substrate 5 or the array substrate 10.

On the other hand, the above-mentioned liquid crystal display device is the most attracting display element until now because of the light weight and low power consumption, but the liquid crystal display device is not a light emitting device but a light receiving device and because of the technical limitations such as brightness, contrast ratio and viewing angle, Development of new display devices that can overcome the disadvantages is actively being developed.

Organic Light Emitting Diode (OLED), one of the new flat panel displays, is self-luminous, so it has better viewing angle and contrast ratio than liquid crystal displays, and it is lightweight because it does not require backlight. It is also advantageous in terms of power consumption. In addition, there is an advantage that the DC low-voltage drive is possible and the response speed is fast, in particular, it has an advantage in terms of manufacturing cost.

Recently, studies on the large area of the organic light emitting display have been actively conducted, and in order to achieve this, there is a demand for developing a transistor having stable operation and durability by securing a constant current characteristic as a driving transistor of the organic light emitting display.

Amorphous silicon thin film transistors used in the above-described liquid crystal display device can be fabricated in a low temperature process, but have very low mobility and do not satisfy the constant current bias condition. Polycrystalline silicon thin film transistors, on the other hand, have high mobility and satisfactory constant current test conditions, and are difficult to obtain uniform characteristics, making it difficult to large area and require high temperature processes.

Accordingly, an oxide thin film transistor in which an active layer is formed of an oxide semiconductor is being developed. In this case, when the oxide semiconductor is applied to a thin film transistor having a bottom gate structure, an etching process of a source / drain electrode, particularly a dry type using plasma There is a problem that the oxide semiconductor is damaged during etching and causes denaturation.

To prevent this, an etch stopper may be additionally formed on the active layer as a barrier layer. In this case, the oxide semiconductor deterioration problem may be solved due to the hydrogen doping effect. It is not there.

2 is a cross-sectional view schematically illustrating a structure of a general oxide thin film transistor.

As shown in the drawing, a general oxide thin film transistor includes a gate electrode 21 formed on the substrate 10, a gate insulating film 15a formed on the gate electrode 21, and an active semiconductor formed on the gate insulating film 15a. The layer 24, the source / drain electrodes 22 and 23 electrically connected to a predetermined region of the active layer 24, the passivation layer 15b and the drain electrode formed on the source / drain electrodes 22 and 23. 23 and a pixel electrode 18 electrically connected thereto.

In this case, the protective film and the etch stopper are generally formed of a silicon oxide film (SiO ₂ ), and plasma enhanced chemical vapor deposition using a mono silane (SiH ₄ ) gas and a nitrogen dioxide (N ₂ O) gas as a deposition gas. It is formed by using Vapor Deposition (PECVD) equipment.

However, in the oxide semiconductor constituting the active layer, the back channel region of the oxide semiconductor is changed to a conductor due to the hydrogen doping effect induced in the SiH ₄ gas during deposition of SiO ₂ using the plasma chemical vapor deposition equipment. do. That is, in general, an oxide semiconductor has both characteristics of a conductor and a semiconductor, and may be transferred by controlling a carrier concentration in a thin film. However, when the hydrogen ions organically dispersed in the SiH ₄ gas diffuse into the oxide semiconductor thin film, they act as donors, thereby transferring the oxide semiconductor to the conductor.

The present invention is to solve the above problems, a ternary system consisting of AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr; x, y, z ≥ 0) It is an object to provide a method for producing an oxide thin film transistor using a component oxide semiconductor as an active layer.

Another object of the present invention is to provide a method of manufacturing an oxide thin film transistor in which an etch stopper is formed in a simple process without a problem of transferring the back channel region to the conductor due to the hydrogen doping effect generated during the deposition of the insulating layer.

Other objects and features of the present invention will be described in the configuration and claims of the invention described below.

In order to achieve the above object, the manufacturing method of the oxide thin film transistor of the present invention comprises the steps of forming a gate electrode on the substrate; Forming a gate insulating film on the substrate on which the gate electrode is formed; Forming an active layer of an oxide semiconductor on the gate insulating film; Forming a silicon layer made of silicon on the substrate on which the active layer is formed by sputtering; Oxidizing the silicon through heat treatment to form an insulating layer made of SiO ₂ ; Selectively patterning the insulating layer to form an etch stopper made of SiO ₂ on the active layer; Forming a source / drain electrode electrically connected to a source / drain region of the active layer on the substrate on which the active layer and the etch stopper are formed; Forming a protective layer on the substrate on which the source / drain electrodes are formed; Removing a portion of the protective layer to form a contact hole exposing a portion of the drain electrode; And forming a pixel electrode electrically connected to the drain electrode through the contact hole, wherein the active layer includes AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr); x, y, z ≧ 0), characterized in that consisting of a quarter- or quad-component oxide semiconductor consisting of a combination.

As described above, the method of manufacturing the oxide thin film transistor according to the present invention has an excellent uniformity by using an amorphous oxide semiconductor as an active layer, thereby providing an effect applicable to a large area display.

In addition, the method of manufacturing the oxide thin film transistor according to the present invention provides an effect of reducing cost and securing device characteristics by forming an etch stopper in a simple process without the problem that the back channel region is transferred to the conductor.

Hereinafter, exemplary embodiments of a method of manufacturing an oxide thin film transistor according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view schematically illustrating a structure of an oxide thin film transistor according to a first embodiment of the present invention, wherein AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr; x, y, A structure of an oxide thin film transistor using a ternary or tetracomponent oxide semiconductor composed of a combination of z ≧ 0) as an active layer is schematically shown.

As shown in the figure, the oxide thin film transistor according to the first embodiment of the present invention is a gate electrode 121 formed on a predetermined substrate 110, a gate insulating film 115a formed on the gate electrode 121, the gate Source / drain electrodes 122 and 123 electrically connected to the active layer 124 formed of an oxide semiconductor on the insulating film 115a, the etch stopper 125 formed of SiO ₂ , and the source / drain regions of the active layer 124. )

In the oxide thin film transistor according to the first embodiment of the present invention, a protective layer 115b formed on the substrate 110 on which the source / drain electrodes 122 and 123 are formed and a contact hole formed in the protective layer 115b are provided. The pixel electrode 118 is electrically connected to the drain electrode 123 through.

In this case, although not shown in the drawing, the gate electrode 121 is connected to a predetermined gate line, and a portion of the source electrode 122 extends in one direction to be connected to the data line, and the gate line and the data line are connected to a substrate ( 110 is arranged vertically and horizontally to define the pixel region.

Here, the oxide thin film transistor according to the first embodiment of the present invention is made of a combination of AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr; x, y, z ≥ 0) As the active layer 124 is formed using a ternary or quaternary oxide semiconductor, it satisfies high mobility and constant current test conditions and ensures uniform characteristics to provide a large area display including a liquid crystal display and an organic light emitting display. It has the advantage of being applicable.

In addition, recently, a tremendous interest and activity has been focused on transparent electronic circuits, and oxide thin film transistors using the oxide semiconductor as an active layer have high mobility and can be manufactured at low temperatures, and thus can be used in the transparent electronic circuits. There is this.

In addition, since the oxide semiconductor may have a wide band gap, it is possible to manufacture UV light emitting diodes (LEDs), white LEDs, and other components having high color purity, and may be processed at low temperatures to produce light and flexible products. It has features that can be.

In the oxide thin film transistor according to the first exemplary embodiment of the present invention, the etch stopper 125 is disposed between the source electrode 122 and the drain electrode 123 on the channel region of the active layer 124. ), The etch stopper 125 serves to prevent the carrier concentration of the channel region from being changed by the plasma treatment in a post-process.

In addition, the oxide thin film transistor according to the first embodiment of the present invention by depositing silicon in a sputtering equipment that does not contain hydrogen, by forming a SiO ₂ through a predetermined heat treatment to use as an etch stopper 125 The deterioration of the oxide semiconductor due to the hydrogen doping effect can be prevented, which will be described in detail through the following method of manufacturing the oxide thin film transistor.

4A through 4F are cross-sectional views sequentially illustrating a process of manufacturing the oxide thin film transistor illustrated in FIG. 3.

As shown in FIG. 4A, a predetermined gate electrode 121 is formed on the substrate 110 made of a transparent insulating material.

At this time, the oxide semiconductor applied to the oxide thin film transistor of the present invention can be deposited at a low temperature, it is possible to use a substrate 110 that can be applied to low-temperature processes such as plastic substrate, soda lime glass. In addition, because of the amorphous properties, it is possible to use the large-area display substrate 110.

In addition, the gate electrode 121 is formed by depositing a first conductive layer on the entire surface of the substrate 110 and then selectively patterning the same through a photolithography process (first mask process).

The first conductive layer may include aluminum (Al), aluminum alloy (Al alloy), tungsten (W), copper (Cu), nickel (Ni), chromium (Cr), Low resistance opaque conductive materials such as molybdenum (Mo), titanium (Ti), platinum (platinum; Pt), tantalum (Ta), and the like may be used. In addition, the first conductive layer may be a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), and the conductive material may be stacked in two or more types. It can also be formed into a multi-layered structure.

Next, as shown in FIG. 4B, an inorganic insulating film or hafnium oxide (Hf) oxide, such as a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ), is formed on the entire surface of the substrate 110 on which the gate electrode 121 is formed. A gate insulating film 115a made of a highly dielectric oxide film such as aluminum oxide is formed.

In addition, an oxide semiconductor layer including a predetermined oxide semiconductor is formed on the entire surface of the substrate 110 on which the gate insulating film 115a is formed, and then selectively patterned through a photolithography process (second mask process) to form the gate electrode 121. The active layer 124 made of the oxide semiconductor is formed on the top of the substrate.

In this case, the oxide semiconductor layer may be, for example, a ternary or tetracomponent oxide composed of a combination of AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr; x, y, z ≥ 0). It can be formed with a semiconductor.

Next, as shown in FIG. 4C, after the predetermined silicon layer is formed on the entire surface of the substrate 110 on which the active layer 124 is formed using sputtering equipment, a predetermined heat treatment process is performed to form the silicon layer. By oxidation, an insulating layer made of SiO ₂ is formed.

In this case, an insulating layer disposed on the active layer 124 serves to protect the back channel of the active layer 124, and the silicon layer may be formed during sputtering using a silicon (Si) target. For example, it is possible to prevent deterioration of the oxide semiconductor due to H ₂ gas in the process by injecting and depositing only N ₂ gas.

When the insulating layer is selectively patterned through a photolithography process (third mask process), an etch stopper 125 made of SiO ₂ is formed on the active layer 124 of the substrate 110. .

In this case, dry etching such as oxygen plasma treatment may be used to etch the insulating layer. While the insulating layer is etched, the lower portion thereof, particularly the back channel region of the active layer 124, is completely prevented from exposure and thus unstable due to exposure. The removal of the etch stopper 125 can be prevented at the same time.

In addition, a predetermined region of the active layer 124 exposed when the insulating layer is etched through oxygen plasma treatment to form the etch stopper 125 has a resistance reduced by oxygen plasma, so that a source / drain electrode will be described later. A source / drain region, which is a contact region with, is formed. However, the present invention is not limited thereto. After forming the etch stopper 125, the resistance of the active layer 124 exposed through surface treatment or heat treatment, such as oxygen plasma, is reduced, so that the source / drain is a contact region. Regions may also be formed.

Next, as shown in FIG. 4D, a second conductive layer is formed on the entire surface of the substrate 110 on which the etch stopper 125 is formed.

In this case, the second conductive layer may use a low resistance opaque conductive material such as aluminum, aluminum alloy, tungsten, copper, nickel, chromium, molybdenum, titanium, platinum, tantalum, etc. to form a source electrode and a drain electrode. In addition, the second conductive layer may be formed of a transparent conductive material such as indium tin oxide, indium zinc oxide, or a multilayer structure in which two or more conductive materials are stacked.

The source electrode 122 and the drain electrode 123 electrically connected to the source and drain regions of the active layer 124 by selectively patterning the second conductive layer through a photolithography process (fourth mask process). Will form.

Next, as shown in FIG. 4E, the passivation layer 115b is formed on the entire surface of the substrate 110 on which the source / drain electrodes 122 and 123 are formed, and then selectively selected through a photolithography process (a fifth mask process). The contact hole 140 is formed in the substrate 110 to expose a portion of the drain electrode 123.

As shown in FIG. 4F, after forming the third conductive film on the entire surface of the substrate 110 on which the protective film 115b is formed, the substrate 110 is selectively removed by a photolithography process (sixth mask process). A pixel electrode 118 formed of the third conductive layer and electrically connected to the drain electrode 123 through the contact hole 140.

In this case, the third conductive layer includes a transparent conductive material having excellent transmittance such as indium tin oxide or indium zinc oxide to form the pixel electrode 118.

The active layer and the etch stopper may be formed through a single mask process by using a half-tone mask or a diffraction mask (hereinafter, referred to as a half-tone mask). This will be described in detail with reference to the following drawings.

5A through 5E are cross-sectional views sequentially illustrating a manufacturing process of an oxide thin film transistor according to a second exemplary embodiment of the present invention.

As shown in FIG. 5A, a predetermined gate electrode 221 is formed on a substrate 210 made of a transparent insulating material.

In this case, the gate electrode 221 is formed by depositing a first conductive layer on the entire surface of the substrate 210 and then selectively patterning the same through a photolithography process (first mask process).

Next, as shown in FIG. 5B, after the gate insulating film 215a and the oxide semiconductor layer made of the oxide semiconductor and the insulating layer made of SiO ₂ are formed on the entire surface of the substrate 210 on which the gate electrode 221 is formed, By selectively patterning the photolithography process (second mask process), an active layer 224 made of the oxide semiconductor and an etch stopper 225 made of SiO ₂ are formed on the gate electrode 221.

In this case, the second mask process uses a half-tone mask, which will be described in detail with reference to the accompanying drawings.

6A to 6F are cross-sectional views illustrating a second mask process according to the second embodiment of the present invention illustrated in FIG. 5B.

As shown in FIG. 6A, a gate insulating layer 215a made of a predetermined insulating material and an oxide semiconductor layer 220 made of an oxide semiconductor are formed on the entire surface of the substrate 210 on which the gate electrode 221 is formed.

In this case, the oxide semiconductor layer may be, for example, a ternary or tetracomponent oxide composed of a combination of AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr; x, y, z ≥ 0). It can be formed with a semiconductor.

In addition, after forming a predetermined silicon layer on the entire surface of the substrate 210 by using a sputtering equipment, a predetermined heat treatment process is performed to oxidize the silicon layer to form an insulating layer 215 made of SiO ₂ .

In this case, the insulating layer 215 disposed on the oxide semiconductor layer 220 serves to protect the back channel of the active layer, and the silicon layer injects only N ₂ gas, for example, during sputtering using a silicon target. By vapor deposition, it is possible to prevent deterioration of the oxide semiconductor due to H ₂ gas in the process.

Next, as shown in FIG. 6B, after forming a photoresist film 270 made of a photoresist such as photoresist on the entire surface of the array substrate 210, the photoresist film 270 is formed through a half-tone mask 280. Selectively irradiates light.

In this case, the half-tone mask 280 blocks the first transmission region I through which all of the irradiated light is transmitted, the second transmission region II through which only a part of the light is transmitted and partly blocks and blocks all the irradiated light. The region III is provided, and only the light passing through the half-tone mask 280 is irradiated to the photosensitive film 270.

Subsequently, after the photosensitive film 270 exposed through the half-tone mask 280 is developed, light passes through the blocking region III and the second transmission region II, as shown in FIG. 6C. The first photoresist pattern 270a to the third photoresist pattern 270c having a predetermined thickness remain in the blocked or partially blocked region, and the photoresist is completely removed in the first transmission region I through which all light is transmitted. The surface of the insulating layer 215 is exposed.

In this case, the first photoresist layer pattern 270a formed in the blocking region III is thicker than the second photoresist layer pattern 270b and the third photoresist layer pattern 270c formed through the second transmission region II. In addition, the photosensitive film is completely removed in a region where all the light is transmitted through the first transmission region I. This is because the photoresist of the positive type is used, and the present invention is not limited thereto. May be used.

Next, as shown in FIG. 6D, when the first photoresist pattern 270a to the third photoresist pattern 270c formed as a mask is used as a mask, the oxide semiconductor layer and the insulating layer formed thereunder are selectively patterned. The active layer 224 made of the oxide semiconductor is formed on the gate electrode 221 of the array substrate 210.

In this case, an insulating layer pattern 215 ′ formed of SiO ₂ and patterned in substantially the same shape as the active layer 224 is formed on the active layer 224.

Subsequently, when an ashing process of removing a part of the thickness of the first photoresist pattern 270a to the third photoresist pattern 270c is performed, as shown in FIG. 6E, the second transmission region II is formed. The second photoresist pattern and the third photoresist pattern of are completely removed.

In this case, the first photoresist pattern may be a fourth photoresist pattern 270a ′ removed by the thickness of the second photoresist pattern and the third photoresist pattern and remain only in the channel region corresponding to the blocking region III.

Subsequently, as illustrated in FIG. 6F, when the insulating layer pattern formed under the fourth photoresist pattern 270a ′ is used as a mask, the active layer 224 of the array substrate 210 is selectively patterned. An etch stopper 225 made of SiO ₂ is formed on the top.

In this case, dry etching such as oxygen plasma treatment may be used for etching the insulating layer pattern, and while the insulating layer pattern is etched, the lower part of the insulating layer pattern, particularly the back channel region of the active layer 224, is completely prevented from exposure and thus unstable due to exposure. At the same time, the damage caused by the patterning of the etch stopper 225 can be prevented.

In addition, a predetermined region of the active layer 224 exposed when the insulating layer pattern is etched through an oxygen plasma process to form the etch stopper 225 has a resistance reduced by oxygen plasma, so that a source / drain electrode to be described later will be described. A source / drain region, which is a contact region with, is formed. However, the present invention is not limited thereto. After forming the etch stopper 225, the resistance of the active layer 224 exposed through the surface treatment or heat treatment such as oxygen plasma is reduced to reduce the source / drain as a contact region. It can also form an area.

Next, as shown in FIG. 5C, a second conductive layer is formed on the entire surface of the substrate 210 on which the etch stopper 225 is formed.

The source electrode 222 and the drain electrode 223 electrically connected to the source and drain regions of the active layer 224 by selectively patterning the second conductive layer through a photolithography process (third mask process). Will form.

Next, as shown in FIG. 5D, after the passivation layer 215b is formed on the entire surface of the substrate 210 on which the source / drain electrodes 222 and 223 are formed, the photolithography process (fourth mask process) is optionally performed. The contact hole 240 is formed in the substrate 210 to expose a portion of the drain electrode 223.

As shown in FIG. 5E, after forming a third conductive film on the entire surface of the substrate 210 on which the protective film 215b is formed, the substrate 210 is selectively removed by a photolithography process (a fifth mask process). A pixel electrode 118 formed of the third conductive layer and electrically connected to the drain electrode 223 through the contact hole 240.

FIG. 7 is a graph illustrating transfer characteristics of an oxide thin film transistor, and illustrates a comparison between transfer characteristics of a general oxide thin film transistor a and an oxide thin film transistor b according to an embodiment of the present invention.

As shown in the figure, the general oxide thin film transistor (a) shows that the back channel region of the oxide semiconductor has been transferred to the conductor due to the hydrogen doping effect in the SiH ₄ gas during the deposition of SiO ₂ using plasma chemical vapor deposition equipment. Can be.

On the other hand, the oxide thin film transistor (b) according to the embodiment of the present invention prevents deterioration of the oxide semiconductor and, as the resistance of the contact region decreases, the transfer curve is steep and the on-current is high, indicating that the transfer characteristics are improved. Can be.

As described above, the present invention can be used not only in a liquid crystal display device but also in another display device manufactured using a thin film transistor, for example, an organic light emitting display device in which an organic light emitting element is connected to a driving transistor.

In addition, the present invention has an advantage that it can be used in a transparent electronic circuit or a flexible display by applying an amorphous zinc oxide-based semiconductor material capable of processing at low temperatures while having a high mobility as an active layer.

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the invention should not be defined by the described embodiments, but should be defined by the claims and their equivalents.

1 is an exploded perspective view schematically showing a general liquid crystal display device.

2 is a cross-sectional view schematically showing the structure of a typical oxide thin film transistor.

3 is a cross-sectional view schematically showing a structure of an oxide thin film transistor according to a first embodiment of the present invention.

4A to 4F are cross-sectional views sequentially illustrating a manufacturing process of the oxide thin film transistor illustrated in FIG. 3.

5A through 5E are cross-sectional views sequentially illustrating a manufacturing process of an oxide thin film transistor according to a second exemplary embodiment of the present invention.

6A to 6F are cross-sectional views showing in detail a second mask process according to the second embodiment of the present invention shown in FIG. 5B.

7 is a graph showing transfer characteristics of an oxide thin film transistor.

DESCRIPTION OF REFERENCE NUMERALS

110,210 substrate 115a, 215a gate insulating film

115b, 215b: passivation layer 118,218: pixel electrode

121,221 gate electrode 122,222 source electrode

123,223 Drain electrode 124,224 Active layer

125,225: etch stopper

Claims (8)

Forming a gate electrode on the substrate; Forming a gate insulating film on the substrate on which the gate electrode is formed; Forming an active layer of an oxide semiconductor on the gate insulating film; Forming a silicon layer made of silicon on the substrate on which the active layer is formed by sputtering; Oxidizing the silicon through heat treatment to form an insulating layer made of SiO ₂ ; Selectively patterning the insulating layer to form an etch stopper made of SiO ₂ on the active layer; Forming a source / drain electrode electrically connected to a source / drain region of the active layer on the substrate on which the active layer and the etch stopper are formed; Forming a protective layer on the substrate on which the source / drain electrodes are formed; Removing a portion of the protective layer to form a contact hole exposing a portion of the drain electrode; And Forming a pixel electrode electrically connected to the drain electrode through the contact hole, wherein the active layer includes AxByCzO (A, B, C = Zn, Cd, Ga, In, Sn, Hf, Zr; x , y, z ≥ 0) a method of manufacturing an oxide thin film transistor, characterized in that consisting of a quarter- or quad-component oxide semiconductor consisting of a combination. The method of claim 1, wherein the active layer is formed of an amorphous zinc oxide semiconductor. The method of claim 1, wherein the substrate is formed of a glass substrate or a plastic substrate. The method of manufacturing an oxide thin film transistor according to claim 1, wherein a silicon layer made of silicon is formed through sputtering using a silicon target. The method of claim 1, wherein the insulating layer is patterned using dry etching such as oxygen plasma treatment. 6. The active layer of claim 5, wherein the active layer, which is not covered by the etch stopper when the insulating layer is patterned, is reduced in resistance by oxygen plasma to form a source / drain region which is a contact region with the source / drain electrodes. A method of manufacturing an oxide thin film transistor, characterized in that it is formed. The method of claim 5, further comprising reducing the resistance of the exposed active layer by performing surface treatment or heat treatment after the formation of the etch stopper. The method of claim 1, wherein the active layer and the etch stopper are formed by using a half-tone mask in a single mask process.

Images