An oxide thin film transistor, an array substrate, a display panel, and an electronic device

Abstract

The application provides an oxide thin film transistor, an array substrate, a display panel and an electronic device. The oxide thin film transistor comprises an oxide active layer, an etching stop layer, a contact layer, a source electrode and a drain electrode. The etching stop layer is located between the oxide active layer and the contact layer. The etching stop layer comprises a plurality of openings, and the openings expose the oxide active layer. The contact layer fills the openings to contact the oxide active layer. The source electrode and the drain electrode are electrically connected to the oxide active layer through the contact layer. The material of the contact layer and the oxide active layer is indium gallium zinc oxide, and the number of atoms of indium is higher than that of gallium in the contact layer. In this way, the contact resistance between the source electrode and the drain electrode and the oxide active layer is effectively reduced, the contact characteristics are optimized, the electron mobility is improved, and the performance of the oxide thin film transistor is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an oxide thin-film transistor, an array substrate, a display panel and an electronic device. BACKGROUND

[0002] In the display panel industry, oxide thin-film transistors (oxide TFTs) are widely used in large-size organic light emitting diode (OLED) products due to their high mobility. However, in the oxide TFT device structure, the oxide thin-film transistor has a problem of performance to be further improved due to the influence of the high contact resistance caused by the direct contact between the source / drain and the oxide active layer. SUMMARY

[0003] Therefore, the present application aims to provide an oxide thin-film transistor, an array substrate, a display panel and an electronic device, which can effectively reduce the resistance between the source / drain and the oxide active layer, and further improve the performance of the oxide thin-film transistor.

[0004] In a first aspect, an embodiment of the present application provides an oxide thin-film transistor, comprising: an oxide active layer, an etching barrier layer, a contact layer, a source electrode and a drain electrode; wherein,

[0005] The etching barrier layer is located between the oxide active layer and the contact layer, and the etching barrier layer comprises a plurality of openings, and the openings expose the oxide active layer;

[0006] The contact layer fills the openings to contact the oxide active layer;

[0007] The source electrode and the drain electrode are electrically connected to the oxide active layer through the contact layer;

[0008] The materials of the contact layer and the oxide active layer are both indium gallium zinc oxide, and in the contact layer, the number of atoms of indium is higher than that of gallium.

[0009] Optionally, in the contact layer, the number of atoms of indium is higher than that of zinc.

[0010] Optionally, in the contact layer, the atomic ratio of indium gallium zinc includes: In: Ga: Zn = x: 1: 1, x > 1.

[0011] Preferably, x > 1.1.

[0012] Optionally, in the contact layer, the number of atoms of gallium is lower than that of zinc.

[0013] Optionally, the atomic number ratio of indium gallium zinc includes: In: Ga: Zn = x: y: 1, x > 1.1, y < 0.9.

[0014] Optionally, the contact surface of the contact layer and the source and the drain is a plane.

[0015] Optionally, further comprising:

[0016] A gate insulating layer located on the side of the oxide active layer away from the etching stop layer, and the material of the gate insulating layer and the etching stop layer is indium gallium zinc oxide.

[0017] In a second aspect, the embodiments of the present application further provide an array substrate, comprising:

[0018] A substrate;

[0019] A plurality of pixel driving circuits located on the surface of the substrate, and the pixel driving circuit comprises the oxide thin film transistor according to any one of the above.

[0020] In a third aspect, the embodiments of the present application further provide a display panel, comprising the array substrate according to any one of the above.

[0021] In a fourth aspect, the embodiments of the present application further provide an electronic device, comprising the display panel according to any one of the above.

[0022] The embodiments of the present application provide an oxide thin film transistor, an array substrate, a display panel and an electronic device. The oxide thin film transistor comprises an oxide active layer, an etching stop layer, a contact layer, a source and a drain. The oxide thin film transistor is provided with the etching stop layer between the oxide active layer and the contact layer. The etching stop layer comprises a plurality of openings, and the openings expose the oxide active layer. The contact layer fills the openings to contact the oxide active layer. The etching stop layer and the contact layer thus arranged can make the source and the drain electrically connected to the oxide active layer through the contact layer. The material of the contact layer and the oxide active layer is indium gallium zinc oxide. In the contact layer, the atomic number of indium is higher than that of gallium. The electronic mobility of the contact layer can be improved while being easy to implement, the conductor property of the contact layer is enhanced, the contact property between the contact layer and the oxide active layer is good, the contact resistance between the source and the drain and the oxide active layer is effectively reduced, the contact property is optimized, and thus the performance of the oxide thin film transistor is further improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description thereof taken in conjunction with the accompanying drawings, in which like reference characters designate like elements in the figures. The accompanying drawings are intended to provide a further understanding of the present application, and are incorporated and constitute a part of this specification, illustrate embodiments of the present application and explain the principles of the present application, and are not intended to limit the present application. In the drawings, like reference numerals refer to like elements throughout.

[0024] Figure 1 A cross-sectional structure of an oxide thin film transistor in the prior art;

[0025] Figure 2 A cross-sectional structure of an oxide thin film transistor according to an embodiment of the present application;

[0026] Figure 3 A cross-sectional structure of an oxide thin film transistor according to another embodiment of the present application;

[0027] Figure 4 A cross-sectional structure of an oxide thin film transistor according to another embodiment of the present application;

[0028] Figure 5 A structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0030] Figure 1 A cross-sectional structure of an oxide thin film transistor is shown in FIG. 1, which includes a gate electrode 101, a gate insulating layer 102, an oxide semiconductor layer 103, a source electrode 104, and a drain electrode 105. Figure 1As shown, the oxide thin film transistor is formed with a gate electrode 12 on a substrate 11, a gate insulating layer 13 on the gate electrode 12, an oxide active layer 14 on the gate insulating layer 13, an etching stop layer 15 on the oxide active layer 14, and a plurality of openings provided in the etching stop layer 15, and source / drain electrodes 17 in direct contact with the oxide active layer 14 through the openings. The oxide active layer 14 is usually made of indium gallium zinc oxide (IGZO). However, the oxide active layer 14 made of indium gallium zinc oxide usually exhibits semiconductor characteristics and has a large resistance. When the oxide active layer 14 is in direct contact with the source / drain electrodes 17, a large contact resistance is generated between the source / drain electrodes 17 and the oxide active layer 14, resulting in poor contact characteristics, which leads to a small on-state current of the thin film transistor and seriously affects the performance of the thin film transistor.

[0031] To this end, at least one embodiment of the present application provides an oxide thin film transistor, an array substrate, a display panel and an electronic device. The oxide thin film transistor includes an oxide active layer, an etching stop layer, a contact layer, a source electrode and a drain electrode. The oxide thin film transistor is provided with the etching stop layer between the oxide active layer and the contact layer. The etching stop layer includes a plurality of openings, and the openings expose the oxide active layer. The contact layer fills the openings to be in contact with the oxide active layer. The etching stop layer and the contact layer thus arranged can make the source electrode and the drain electrode electrically connected to the oxide active layer through the contact layer. The materials of the contact layer and the oxide active layer are both indium gallium zinc oxide. In the contact layer, the number of indium atoms is higher than that of gallium atoms. The electron mobility of the contact layer can be improved while being easy to implement, the conductor characteristics of the contact layer are enhanced, the contact characteristics between the contact layer and the oxide active layer are good, the contact resistance between the source electrode and the drain electrode and the oxide active layer is effectively reduced, and the contact characteristics are optimized, thereby further improving the performance of the oxide thin film transistor.

[0032] The oxide thin film transistor provided by the embodiments of the present application is described below by way of several examples or embodiments. As described below, different features in these specific examples or embodiments can be combined with each other without mutual contradiction, so as to obtain new examples or embodiments, which also belong to the protection scope of the present disclosure.

[0033] Figure 2 is a cross-sectional structure schematic diagram of an oxide thin film transistor provided by an example embodiment of the present application. As Figure 2 shown, the oxide thin film transistor provided by the embodiments of the present application can include an oxide active layer 14, an etching stop layer 15, a contact layer 16, and source / drain electrodes 17.

[0034] The etching stop layer 15 is located between the oxide active layer 14 and the contact layer 16, and the etching stop layer 15 includes a plurality of openings exposing the oxide active layer 14.

[0035] The contact layer 16 fills the openings to contact the oxide active layer 14.

[0036] The source / drain 17 is electrically connected to the oxide active layer 14 through the contact layer 16.

[0037] The contact layer 16 and the oxide active layer 14 are both indium gallium zinc oxide, and the number of indium atoms is greater than the number of gallium atoms in the contact layer 16.

[0038] In this specification, “a plurality of” means two or more unless otherwise specified.

[0039] It can be seen from Figure 2 The contact layer 16 is added between the source / drain 17 and the etching stop layer 15, and the material of the contact layer 16 is indium gallium zinc oxide, which is the same as the material of the oxide active layer 14. The indium gallium zinc oxide of the oxide active layer 14 exhibits semiconductor properties, with an atomic ratio of In:Ga:Zn = 1:1:1. In order to improve the performance of the thin film transistor and reduce the contact resistance between the oxide active layer 14 and the source / drain 17, the contact layer needs to exhibit conductor properties.

[0040] In order to conveniently obtain a contact layer exhibiting conductor properties, the inventors have found through research that increasing the content of In atoms in IGZO semiconductor material can improve its carrier mobility, and when the number of In atoms is greater than the number of Ga atoms, the IGZO semiconductor material exhibits conductor properties. Therefore, in this embodiment, the content of In atoms in indium gallium zinc oxide is increased, and the number of In atoms in the indium gallium zinc oxide in the contact layer is set to be greater than the number of Ga atoms, so that the indium gallium zinc oxide in the contact layer exhibits conductor properties. Only the In, Ga, and Zn ratio needs to be configured as required during target material production, and then physical vapor deposition equipment is used for film formation. The process conditions are simple, and no special process treatment is required to achieve the conductor properties of the contact layer. While achieving the purpose of electrically connecting the source / drain 17 and the oxide active layer 14 through the contact layer, the purpose of conveniently obtaining a contact layer exhibiting conductor properties is achieved.

[0041] Based on this, the contact layer 16 with the conductive property is added between the source and drain 17 and the etching stop layer 15, and the contact layer 16 and the oxide active layer 14 are made of the same material, which can make the contact layer 16 and the oxide active layer 14 have good contact properties, thereby improving the performance of the oxide thin film transistor.

[0042] In addition, in the IGZO, increasing the number of atoms of indium can improve the carrier mobility, and the addition of gallium can inhibit oxygen vacancies, and the ion orbital radius of gallium is much smaller than that of indium, and the addition of gallium can reduce the overlap of electron orbits and reduce the electron mobility. Therefore, on the basis of the IGZO of the contact layer 16 having the conductive property, increasing the number of atoms of indium and / or reducing the number of atoms of gallium, so that the number of atoms of indium is higher than the number of atoms of gallium, can further improve the conductive properties of the IGZO of the contact layer 16, that is, further improve the conductivity between the oxide active layer 14 and the source and drain of the oxide thin film transistor, thereby further improving the performance of the oxide thin film transistor.

[0043] In addition, in improving the performance of the oxide thin film transistor, on the basis of the original IGZO, increasing the number of atoms of indium and / or reducing the number of atoms of gallium is more simple and easy to implement.

[0044] For example, in the oxide active layer 14, the atomic ratio of indium and gallium is In: Ga = 1: 1. Then, on the basis of this material, only the content of indium is increased so that the number of atoms of indium is greater than the number of atoms of gallium, a contact layer 16 with stronger conductivity can be obtained, that is, an oxide thin film transistor with better performance can be obtained.

[0045] In the exemplary embodiment, in the contact layer 16, the number of atoms of indium can be higher than the number of atoms of zinc. That is, in the contact layer 16, the number of atoms of indium is not only higher than the number of atoms of gallium, but also higher than the number of atoms of zinc. In this way, it can be ensured that indium has a higher proportion of atomic number in indium gallium zinc oxide, which can greatly improve the carrier mobility and make it have stronger conductivity, thereby obtaining an oxide thin film transistor with better conductive performance.

[0046] In the exemplary embodiment, in order to make the contact layer 16 with stronger conductivity easy to implement, the atomic ratio of indium gallium zinc in the contact layer 16 can include In: Ga: Zn = x: 1: 1, where x > 1.

[0047] For example, the material of the oxide active layer 14 is indium gallium zinc oxide, and when it exhibits semiconductor characteristics, the atomic ratio of indium gallium zinc is generally In:Ga:Zn=1:1:1. In the target material, the atomic number of indium in the IGZO material is increased, and / or the atomic number of gallium is reduced, so that the atomic number of indium is greater than the atomic number of gallium and the atomic number of zinc, so as to enhance the conductor characteristics, and then directly deposited by physical vapor deposition to obtain the contact layer 16 with conductor characteristics. In this way, the operation is more simple, and the target material of the contact layer 16 can be obtained by slightly changing the original oxide active layer 14 target material, thereby improving the material utilization rate.

[0048] Preferably, when x>1.1, the conductivity of the indium gallium zinc oxide is better, and the performance of the oxide thin film transistor is also better.

[0049] In the exemplary embodiment, in the contact layer 16, the atomic number of gallium can be lower than the atomic number of zinc. That is, in the contact layer 16, the atomic number of indium is higher than the atomic number of gallium, and the atomic number of gallium is lower than the atomic number of zinc.

[0050] For example, the material of the oxide active layer 14 is indium gallium zinc oxide, and when it exhibits semiconductor characteristics, the atomic ratio of indium gallium zinc is generally In:Ga:Zn=1:1:1. Then, based on this material, the content of indium can be increased while the content of gallium is reduced, or the content of indium and the content of zinc are increased at the same time, and the increased content of indium is higher than the increased content of zinc, so that the atomic number of indium is greater than the atomic number of gallium and the atomic number of zinc, and the atomic number of gallium is lower than the atomic number of zinc, thereby obtaining the contact layer 16 with better conductivity.

[0051] In the exemplary embodiment, when the atomic number of gallium is lower than the atomic number of zinc, the atomic ratio of indium gallium zinc can include In:Ga:Zn=x:y:1, x>1.1, y<0.9. In this way, the atomic number of indium in the indium gallium zinc has a relatively high proportion, and the atomic number of gallium has a relatively low proportion, which can ensure that the carrier mobility is improved while the oxygen vacancies are increased and the electron mobility is improved, thereby effectively reducing the contact resistance and improving the conductivity.

[0052] Of course, in other possible embodiments of the present application, the atomic ratio of indium gallium zinc in the contact layer 16 can also be other ratios that can increase the conductivity of the indium gallium zinc oxide, which is not limited in the present application.

[0053] In the exemplary embodiment, as Figure 3As shown, the contact surface between the contact layer 16 and the source / drain 17 can be planar. In this way, the contact layer 16 fills the opening of the etching stop layer 15 while the side away from the etching stop layer 15 is planar, which makes the subsequent film forming of the source / drain 17 simpler and reduces the process difficulty.

[0054] In an example embodiment, as shown in FIG. 1, the oxide thin film transistor can further include a gate insulating layer 13 on the side of the oxide active layer 14 away from the etching stop layer 15, and the material of the gate insulating layer 13 and the etching stop layer 15 is indium gallium zinc oxide. Figure 4 As shown, the oxide thin film transistor can further include a gate insulating layer 13 on the side of the oxide active layer 14 away from the etching stop layer 15, and the material of the gate insulating layer 13 and the etching stop layer 15 is indium gallium zinc oxide. The indium gallium zinc oxide of the gate insulating layer 13 and the etching stop layer 15 both exhibit insulating medium properties.

[0055] In the film forming process of the oxide thin film transistor, the oxygen content in the indium gallium zinc oxide forming the gate insulating layer 13 and the etching stop layer 15 can be controlled to make the indium gallium zinc oxide exhibit insulating medium properties. In addition, since the gate insulating layer 13, the etching stop layer 15 and the oxide active layer 14 are all materials of the same composition, the matching of the interface of the oxide active layer 14 is improved, thereby further reducing the off-state current of the oxide thin film transistor.

[0056] Of course, the present application is not limited thereto, and in other possible embodiments of the present application, the material of one of the gate insulating layer 13 and the etching stop layer 15 can be indium gallium zinc oxide, or the materials of the gate insulating layer 13 and the etching stop layer 15 can also be silicon oxide or silicon nitride or other insulating materials.

[0057] As another optional implementation of the present application, the embodiments of the present application further provide an array substrate, which can include a substrate, and a plurality of pixel driving circuits on the surface of the substrate, the pixel driving circuit including the oxide thin film transistor as described in any of the above embodiments.

[0058] As another optional implementation of the present application, the embodiments of the present application further provide a display panel, which includes the array substrate as described in any of the above embodiments.

[0059] As another optional implementation of the present application, the embodiments of the present application further provide an electronic device, as shown in FIG. 1, the electronic device B100 includes the display panel as described in any of the above embodiments. Figure 5 As another optional implementation of the present application, the embodiments of the present application further provide an electronic device, as shown in FIG. 1, the electronic device B100 includes the display panel as described in any of the above embodiments.

[0060] The embodiments in the present specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts of each embodiment can be mutually referred to.

[0061] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An oxide thin-film transistor, characterized in that, Comprising: an oxide active layer, an etching stop layer, a contact layer, a source electrode and a drain electrode; wherein, the etching stop layer is located between the oxide active layer and the contact layer, the etching stop layer comprises a plurality of openings, the openings expose the oxide active layer; the contact layer fills the openings to contact the oxide active layer; the source electrode and the drain electrode are electrically connected with the oxide active layer through the contact layer; the material of the contact layer and the oxide active layer is indium gallium zinc oxide, and in the contact layer, the number of atoms of indium is higher than that of gallium; in the contact layer, the number of atoms of indium is higher than that of zinc; in the contact layer, the number of atoms of gallium is lower than that of zinc; in the oxide active layer, the atomic ratio of indium gallium zinc is: In: Ga: Zn = 1: 1:

1.

2. The oxide thin film transistor according to claim 1, wherein in the contact layer, the atomic ratio of indium gallium zinc includes: In: Ga: Zn = x: y: 1, x > 1.1, y < 0.

9.

3. The oxide thin film transistor according to claim 1, wherein the contact surface of the contact layer and the source electrode and the drain electrode is a plane.

4. The oxide thin film transistor according to claim 1, wherein Further comprising: a gate insulating layer located on the side of the oxide active layer away from the etching stop layer, the material of the gate insulating layer and the etching stop layer is indium gallium zinc oxide.

5. An array substrate, characterized by, Comprising: a substrate; a plurality of pixel driving circuits located on the surface of the substrate, the pixel driving circuit comprises at least one oxide thin film transistor as claimed in any one of claims 1-4.

6. A display panel, characterized by, An array substrate as claimed in claim 5 is included.

7. An electronic device, comprising: A display panel as claimed in claim 6 is included.

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