KR102155568B1 - Thin Film Transistor, and Organic Light Emitting Display Using The Same - Google Patents

Abstract

A thin film transistor according to an aspect of the present invention comprises: a first light absorbing film positioned on a substrate; An oxide active layer on the first light absorption layer; A first buffer layer positioned between the oxide active layer and the first light absorbing layer; A gate insulating layer on the oxide active layer; A gate electrode on the gate insulating layer; A second buffer layer on the gate electrode; And a second light absorbing layer disposed on the second buffer layer, wherein a source electrode and a drain electrode are disposed on the second light absorbing layer and connected to the oxide active layer, respectively.

Description

Thin Film Transistor, and Organic Light Emitting Display Using The Same}

The present invention relates to an organic light emitting display (OLED) including a thin film transistor and a thin film transistor, and more specifically, an organic light emitting display device including a thin film transistor and a thin film transistor having improved device characteristics and light reliability It is about.

Recently, the importance of a display device (FPD: Flat Panel Display) is increasing with the development of multimedia. In response, liquid crystal display (LCD), plasma display panel (PDP), field emission display (FED), organic light emitting display device (Organic Light Emitting Device), etc. Various displays are being put into practical use. Among them, the organic light emitting display device has a response speed of less than 1 ms, has a high response speed, low power consumption, and does not have a problem with a viewing angle because it is self-luminous, and thus is attracting attention as a next-generation display device.

Methods of driving the display device include a passive matrix method and an active matrix method using a thin film transistor. In the passive matrix method, the anode and the cathode are formed to be orthogonal to each other and a line is selected to drive, whereas the active matrix method connects the thin film transistor to each pixel electrode 180 and is connected to the gate electrode 140 of the thin film transistor. It is a method of driving according to the maintained voltage.

In a thin film transistor, not only basic characteristics of a thin film transistor such as mobility and leakage current, but also durability and electrical reliability capable of maintaining a long life are very important. Here, the active layer of the thin film transistor is mainly formed of amorphous silicon or polycrystalline silicon. Amorphous silicon has an advantage in that a film formation process is simple and production cost is low, but electrical reliability is not secured. In addition, polycrystalline silicon is very difficult to apply to a large area due to a high process temperature, and there is a problem that uniformity according to the crystallization method is not secured.

On the other hand, when the active layer is formed of oxide, high mobility can be obtained even when the film is formed at a low temperature, and it is very easy to obtain the desired physical properties due to the large change in resistance depending on the content of oxygen, so it is suitable for recent application to thin film transistors. Got a lot of attention. In particular, examples thereof include zinc oxide (ZnO), indium zinc oxide (InZnO), or indium gallium zinc oxide (InGaZnO4). The thin film transistor including the oxide active layer 120 has an unstable characteristic in which a photocurrent is generated by external light, so that improvement in optical reliability is urgently required.

The present invention is to solve the above-described problems, in a thin film transistor using an oxide active layer, a thin film transistor and a thin film capable of improving the characteristics of a thin film transistor and optical reliability of a device by minimizing light incident on the oxide active layer. It is a technical problem to provide an organic light emitting display device including a transistor.

In addition, the present invention is to provide a thin organic light emitting display device by removing a polarizing plate existing on a substrate in order to reduce light incident to the inside of the organic light emitting display device by minimizing the light incident on the oxide active layer. Let it be that technical problem.

A thin film transistor according to an aspect of the present invention for achieving the above object includes: a first light absorption film 110 positioned on a substrate 100; An oxide active layer 120 positioned on the first light absorbing layer 110; A first buffer layer positioned between the oxide active layer 120 and the first light absorbing layer 110; A gate insulating layer on the oxide active layer 120; A gate electrode on the gate insulating layer; A second buffer layer 150 positioned on the gate electrode 140; A second light absorption layer 160 positioned on the second buffer layer 150; And a source electrode 171 and a drain electrode 172 positioned on the second light absorption layer 160 and connected to the oxide active layer 120, respectively.

According to the present invention, the thin film transistor and the organic light emitting display device including the thin film transistor of the present invention have the effect of improving the characteristics of the thin film transistor and the optical reliability of the device by minimizing light incident on the oxide active layer. .

In addition, the organic light emitting display device including the thin film transistor and the thin film transistor of the present invention minimizes light incident to the oxide active layer, thereby reducing the light incident inside the organic light emitting display device. There is an effect of implementing a thin organic light emitting display device by removing the.

1 is a cross-sectional view showing a thin film transistor according to an embodiment of the present invention.
2 is a plan view showing a thin film transistor according to an embodiment of the present invention.
3 is a cross-sectional view illustrating an organic light emitting display device to which a thin film transistor is applied according to an embodiment of the present invention.
4 is a cross-sectional view showing a thin film transistor according to another embodiment of the present invention.

The same reference numerals refer to the same components throughout the specification.

Although the first, second, and the like are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are only used to distinguish one component from another component. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical idea of the present invention.

The size and thickness of each component shown in the drawings are illustrated for convenience of description, and the present invention is not limited to the size and thickness of the illustrated component.

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, and as a person skilled in the art can fully understand, technically various interlocking and driving are possible, and each embodiment may be independently implemented with respect to each other. It may be possible to do it together in a related relationship.

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

1 is a cross-sectional view of a thin film transistor 1000 including an oxide active layer 120 according to an embodiment of the present invention.

When described in detail with reference to FIG. 1, a first light absorbing layer 110 is positioned on a substrate 100. The substrate 100 is made of glass, plastic having softness, or metal. The first light absorbing layer 110 includes a material capable of blocking or absorbing light, and is made of an oxide-based black dye and a high heat-resistant black resin. The substrate 100 and the first light absorbing layer 110 The first buffer layer 111 is positioned thereon. The first buffer layer 111 is for preventing impurities such as alkali ions flowing out of the substrate 100 from penetrating into the thin film transistor, and the first buffer layer 111 is formed of silicon oxide (SiO2) and/or silicon nitride ( It may be a single layer or multiple layers made of SiNx).

An oxide active layer 120 is positioned on the first buffer layer 111. The oxide active layer 120 may be formed by depositing an oxide semiconductor material and then patterning in such a manner that only an oxide semiconductor having a desired size of the oxide active layer 120 is left.

As a method of forming the oxide active layer 120, sputtering, chemical vapor deposition (CVD), atomic layer deposition (ALD), or the like may be used.

Various metal oxides may be used as the oxide semiconductor of the oxide active layer 120. For example, as a constituent material of an oxide semiconductor, an indium tin gallium zinc oxide (InSnGaZnO)-based material as a quaternary metal oxide, an indium gallium zinc oxide (InGaZnO)-based material as a ternary metal oxide, and an indium tin zinc oxide (InSnZnO)-based material , Indium aluminum zinc oxide (InAlZnO)-based material, indium hafnium zinc oxide (InHfZnO), tin gallium zinc oxide (SnGaZnO)-based material, aluminum gallium zinc oxide (AlGaZnO)-based material, tin aluminum zinc oxide (SnAlZnO)-based material, 2 Indium zinc oxide (InZnO)-based materials, tin-zinc oxide (SnZnO)-based materials, aluminum zinc oxide (AlZnO)-based materials, zinc magnesium oxide (ZnMgO)-based materials, tin magnesium oxide (SnMgO)-based materials, indium Magnesium oxide (InMgO)-based materials, indium gallium oxide (InGaO)-based materials, indium oxide (InO)-based materials, tin oxide (SnO)-based materials, zinc oxide (ZnO)-based materials, and the like can be used. The composition ratio of each element included in each material used to form the oxide semiconductor is not particularly limited and can be variously adjusted.

A gate electrode 140 formed to overlap at least a portion is positioned on the oxide active layer 120. The gate electrode 140 is formed of a conductive material. The gate electrode 140 is, for example, molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be made of any one or an alloy thereof, but is not limited thereto, and may be formed of various materials. In addition, the gate electrode 140 is a group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be a multilayer made of any one selected from or an alloy thereof.

A gate insulating layer 130 is positioned between the oxide active layer 120 and the gate electrode 140. The gate insulating layer 130 may be a silicon oxide (SiO2), a silicon nitride (SiNx), or a multilayer made of them.

1, the gate electrode 140 is formed to have substantially the same width as the gate insulating layer 130. That is, the area of the surface of the gate electrode 140 in contact with each other and the area of the surface of the gate insulating layer 130 are substantially the same. In this specification, that the two components have "substantially the same size" is not only the case when the two component sizes are exactly the same, but also by the manufacturing process (ie, deviation due to the manufacturing process). It is meant to include cases that do not have exactly the same size. For example, one of the gate electrode 140 or the gate insulating layer 130 may be slightly larger than the other by over-etching during a manufacturing process. In the above-described case, the gate electrode 140 and the gate insulating layer 130 may be formed to have a tapered shape so that the surface of the gate electrode 140 and the surface of the gate insulating layer 130 in contact with each other have slightly different sizes. have.

In order for the gate electrode 140 and the gate insulating layer 130 to have substantially the same surface area, the gate insulating layer 130 and the gate electrode 140 are sequentially stacked, and then the same mask is patterned by a process. Is formed.

During the patterning process of the gate electrode 140 and the gate insulating layer 130, both sides of the oxide semiconductor are doped with impurities to become conductors. In this case, both sides are provided with a source region 121 and a drain region 123, respectively, and a channel region 122 is provided between the source region 121 and the drain region 123. The channel region 122 is positioned to correspond to the gate insulating layer 130 and the gate electrode 140.

A second light absorption layer 160 is positioned on the gate electrode 140. The second light-absorbing film 160 includes a material capable of blocking or absorbing light, such as the first light-absorbing film 110, and is made of an oxide-based black dye and a black matrix such as a high heat-resistant black resin.

The second light absorbing layer 160 may be patterned by applying the oxide active layer 120, the gate insulating layer 130, and the upper and side portions of the gate electrode 140 to be completely covered.

A second buffer layer 150 is positioned between the gate electrode 140 and the second light absorbing layer 160. The second buffer layer 150 is an inorganic material, and may be a silicon oxide (SiO2), a silicon nitride (SiNx), or a multilayer made of these.

Like the second light absorbing layer 160, the second buffer layer 150 is patterned by coating so as to completely cover the top and sides of the oxide active layer 120, the gate insulating layer 130, and the gate electrode 140.

The reason for forming the second buffer layer 150 is that when the second buffer layer 150 is used as an organic material such as a black resin, the second buffer layer 150 is located under the gas containing impurities generated during the patterning process. This is because the performance of the thin film transistor is degraded by affecting the oxide active layer 120 and causing a decrease in electron mobility or a change in the threshold voltage Vth.

Meanwhile, after sequentially applying the second buffer layer 150 and the second light absorbing layer 160, the second buffer layer 150 and the second light absorbing layer 160 may be formed at the same time by patterning with one mask. have.

Alternatively, the second light absorbing layer 160 may be formed to correspond to an area corresponding to the channel region 122.

An intermediate insulating layer 112 is positioned on the second light absorption layer 160. The intermediate insulating layer may be silicon oxide (SiO2), silicon nitride (SiNx), or a multilayer made of them.

A source electrode 171 and a drain electrode 172 are positioned on the intermediate insulating layer. The source electrode 171 and the drain electrode 172 may be formed of a single layer or multiple layers, and in the case of a single layer, molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti) , Nickel (Ni), neodymium (Nd) and copper (Cu) may be made of any one selected from the group consisting of, or an alloy thereof. In addition, when the source electrode 171 and the drain electrode 172 are multilayers, it is a double layer of molybdenum/aluminum-neodymium, molybdenum/aluminum, or titanium/aluminum, or molybdenum/aluminum-neodymium/molybdenum, molybdenum/aluminum/molybdenum or titanium. It can be made of three layers of /aluminum/titanium.

The source electrode 171 and the drain electrode 172 pass through the intermediate insulating layer 112, the second light absorbing layer 160, and the second buffer layer 150, and the source region 121 of the oxide active layer 120 and the They are connected through a first contact hole CNT1 and a second contact hole CNT2 exposing the drain region 123, respectively.

A protective layer 113 is disposed on the substrate 100 and the source/drain electrodes 172. The drain electrode 172 is connected to the pixel electrode 180 through a drain contact hole DCNT penetrating the passivation layer 113.

2 is a plan view showing a thin film transistor 1000 according to an embodiment of the present invention shown in FIG. 1.

According to FIG. 2, it is preferable that the width of the first light absorbing layer 110 is equal to or wider than the width of the oxide active layer 120. In the drawing, the second light absorption layer 160 is shown to be formed wider than the oxide active layer 120, but may be formed to correspond to the channel region 122 of the oxide active layer 120.

3 is a cross-sectional view illustrating an organic light emitting display device 2000 according to an exemplary embodiment of the present invention.

Referring to FIG. 3, in the organic light emitting display device, a thin film transistor and an organic light emitting layer 220 are positioned on a substrate 100, and a sealing substrate 200 is formed on the substrate 100 to form a thin film together with the substrate 100. It is configured to seal the transistor 1000 and the organic emission layer 220. The sealing substrate 200 may be formed of an insulating substrate 100 such as glass or plastic having transparency, and moisture remaining between the sealing substrate 200 and the substrate 100 on the lower surface of the sealing substrate 200 A transparent absorbent (not shown) and a color filter (not shown) that absorb moisture may be formed. Each component of the thin film transistor, a first light absorption layer 110, a first buffer layer 111, an oxide active layer 120, a gate insulating layer 130, a gate electrode 140, a source electrode 171, and a drain Since the electrode 172 is substantially the same as the components of the thin film transistor 1000 described in FIGS. 3A and 3B, detailed descriptions will be omitted.

A protective layer 113 is positioned on the substrate 100 including the source electrode 171 and the drain electrode 172.

The protective layer 113 may be a silicon oxide (SiO2), a silicon nitride (SiNx), or a multilayer made of them.

A first metal electrode 210 is positioned on the passivation layer 113. The first metal electrode 210 is connected to the drain electrode 172 of the thin film transistor through a drain contact hole DCNT penetrating the passivation layer 113.

The first metal electrode 210 is made of one material selected from the group consisting of indium tin oxide (ITO), silver (Ag), and aluminum (Al).

When the organic light emitting display device has a lower emission structure, it is preferable to form a transparent material such as ITO.

A bank layer 230 is formed on the first metal electrode 210 at a position for partitioning the sub-pixels.

An organic layer is stacked on the first metal electrode 210 and the bank layer 230 to form the organic emission layer 220.

A second metal electrode 240 is positioned on the organic emission layer 220.

On the other hand, between the first metal electrode 210 and the organic light emitting layer 220, an electron injection layer or an electron transport layer, or both, to assist electron transfer, depending on the material of the first metal electrode 210 and the organic light emitting layer 220. Can be included.

In addition, between the organic emission layer 220 and the second metal electrode 240, depending on the material of the second metal electrode 240 and the organic emission layer 220, a hole injection layer or a hole transport layer to aid hole injection and transfer, or both. You can include all.

A thin film encapsulation (TFE) 250 is positioned on the second metal electrode 240. The thin film encapsulation layer 250 may be formed as a multilayered film made of organic and inorganic materials to compensate for the organic light emitting layer 220 being vulnerable to moisture.

An adhesive layer 260 for bonding with the sealing substrate 200 is positioned on the thin film encapsulation layer 250.

In the thin film transistor and organic light emitting display device according to an exemplary embodiment of the present invention, light incident to the oxide active layer 120 of the thin film transistor by an external light source and an internal light source is transmitted to the first light absorbing layer 110 and the first light absorbing layer 110. 2 By reflecting and absorbing through the light absorption layer 160, there is an effect of improving the optical reliability of the oxide active layer 120 and further improving the performance of the thin film transistor and the organic light emitting display device.

In addition, the organic light emitting display device 2000 according to an exemplary embodiment of the present invention provides a thin organic light emitting display device by removing a polarizing plate used to prevent an external light source from entering the organic light emitting display device. There is an effect that can be implemented.

Meanwhile, FIG. 4 is a cross-sectional view illustrating a thin film transistor according to another embodiment of the present invention.

When described in detail with reference to FIG. 4, a first light absorbing layer 310 is positioned on the substrate 300. A first buffer layer 311 is formed on the first light absorbing layer 310. A gate electrode 340, a gate insulating layer 330, and an oxide active layer 320 are sequentially disposed on the first buffer layer 311. A second buffer layer 350 is positioned on the oxide active layer 320 so as to completely cover upper and side portions of the oxide active layer 320. It is preferable that the second light absorption layer 360 is positioned on the second buffer layer 350 and is formed to surround the top and side surfaces of the oxide active layer 320 like the second buffer layer 350.

A protective layer 312 is formed on the substrate 300 and the second light absorbing layer 360. On the passivation layer 312, the source electrode 371 and the drain electrode 372 pass through the second buffer layer 350, the second light absorbing layer 360, and the passivation layer 312 through a contact hole. Connected to 320.

In the thin film transistor according to another embodiment of the present invention, light incident to the oxide active layer 320 of the thin film transistor by an external light source and an internal light source is transmitted to the first light absorbing layer 310 and the second light absorbing layer 360. ) Through reflection and absorption, thereby improving the optical reliability of the oxide active layer 320 and further increasing the performance of the thin film transistor.

Those skilled in the art to which the present invention pertains will appreciate that the above-described present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof.

Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

100: substrate 100 110: first light absorbing film 110
111: first buffer layer 120: oxide active layer 120
130: gate insulating layer 140: gate electrode 140
150: second buffer layer 150 160: second light absorbing layer 160

Claims (7)

A first light absorbing film positioned on the substrate;
An oxide active layer on the first light absorption layer;
A first buffer layer positioned between the oxide active layer and the first light absorbing layer;
A gate insulating layer on the oxide active layer;
A gate electrode on the gate insulating layer;
A second buffer layer on the gate electrode;
A second light absorbing layer on the second buffer layer;
An intermediate insulating layer formed on the substrate on which the second light absorbing layer is formed; And
And a source electrode and a drain electrode formed on the intermediate insulating layer,
The second buffer layer covers an upper surface and a side surface of the gate electrode and an upper surface and a side surface of the oxide active layer,
The second light absorbing layer covers the top and side surfaces of the second buffer layer,
The source electrode and the drain electrode are respectively connected to the oxide active layer through a contact hole formed in the intermediate insulating layer, the second light absorbing layer, and the second buffer layer.
The method of claim 1,
The first and second light absorption layers are thin film transistors, characterized in that made of any one of an oxide-based black dye and a high heat-resistant black resin.
delete delete delete The method of claim 1,
The first and second buffer layers are thin film transistors, characterized in that the single layer or multi-layer formed of SiO2 or SiNx.
A thin film transistor positioned on the substrate;
A first metal electrode connected to the thin film transistor;
A second metal electrode on the first metal electrode; and
And an organic light emitting layer formed between the first metal electrode and the second metal electrode,
The thin film transistor includes a first light absorbing layer disposed on the substrate, an oxide active layer disposed on the first light absorbing layer, and a first buffer layer disposed between the oxide active layer and the first light absorbing layer And, a gate insulating layer on the oxide active layer, a gate electrode on the gate insulating layer, a second buffer layer on the gate electrode, and a second light absorption layer on the second buffer layer. And, an intermediate insulating layer formed on the substrate on which the second light absorbing layer is formed, a source electrode formed on the intermediate insulating layer, and a drain electrode formed on the intermediate insulating layer and connected to the first metal electrode,
The second buffer layer covers an upper surface and a side surface of the gate electrode and an upper surface and a side surface of the oxide active layer,
The second light absorbing layer covers the top and side surfaces of the second buffer layer,
Wherein the source electrode and the drain electrode are respectively connected to the oxide active layer through a contact hole formed in the intermediate insulating layer, the second light absorbing layer, and the second buffer layer.

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