A metal oxide thin film transistor backplane

Abstract

This invention provides a metal oxide thin-film transistor (METS) backplane. The METS backplane includes: a first METS and a second METS; the first METS includes a first active layer having a first mobility, the first active layer comprising a first METS thin film; the second METS includes a second active layer having a second mobility, the second active layer comprising a second METS thin film, the second mobility being less than the first mobility. By selecting different active layer materials and active layer structures, TFTs with different mobilities can be placed on the backplane, allowing users to select different TFTs for GOA and AA region circuit design according to actual needs, thereby enabling the TFT backplane to simultaneously possess high performance and high stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thin film transistor backplane, and particularly relates to a metal oxide thin film transistor backplane. BACKGROUND

[0002] Metal oxide thin film transistors (TFTs) are often used in display backplanes. With the improvement of display performance, the display gradually increases the requirement for the mobility of metal oxide TFTs in the backplane. However, the higher the mobility of the metal oxide TFT is, the poorer the stability is. For example, under the same design and the same working environment, the effectiveness of the high-mobility device is significantly reduced.

[0003] Therefore, how to effectively improve the stability of the backplane of the metal oxide TFT with high mobility becomes a technical problem to be solved. SUMMARY

[0004] The metal oxide thin film transistor backplane provided by the embodiment of the present application can realize the metal oxide TFT backplane with high performance and high stability. The specific technical solutions are as follows.

[0005] In a first aspect of the embodiment of the present application, a metal oxide thin film transistor backplane is provided, and the metal oxide TFT backplane comprises:

[0006] a first metal oxide TFT and a second metal oxide TFT.

[0007] The first metal oxide TFT comprises a first active layer with a first mobility, and the first active layer comprises a first metal oxide thin film.

[0008] The second metal oxide TFT comprises a second active layer with a second mobility, and the second active layer comprises a second metal oxide thin film, and the second mobility is less than the first mobility.

[0009] In a possible embodiment, the difference between the first mobility and the second mobility is at least not less than 10.

[0010] In a possible embodiment, the first metal oxide thin film is at least one metal oxide semiconductor layer.

[0011] The second metal oxide thin film is at least one metal oxide semiconductor layer.

[0012] In a possible embodiment, the first active layer is composed of a single-layer first metal oxide thin film.

[0013] The second active layer is composed of a single-layer second metal oxide thin film;

[0014] The second metal oxide thin film comprises IGZO;

[0015] The first metal oxide thin film has a mobility of 15-20 cm 2 Vs or above.

[0016] In a possible embodiment, the first active layer is composed of a plurality of metal oxide thin film layers;

[0017] The second active layer is composed of a single-layer metal oxide thin film;

[0018] The metal oxide thin film of the second active layer is the same layer of metal oxide film as one of the plurality of metal oxide thin film layers.

[0019] In a possible embodiment, the first active layer comprises a metal oxide composed of at least two metals selected from indium, gallium, zinc, tin, tungsten, tantalum and lanthanide elements.

[0020] The second active layer comprises a metal oxide composed of at least two metals selected from indium, gallium and zinc.

[0021] In a possible embodiment, the first metal oxide TFT and the second metal oxide TFT are TFTs in a gate driving circuit, the first metal oxide TFT is a driving TFT for controlling the output signal of the output end of the gate driving circuit, and the second metal oxide TFT is a switching TFT for controlling the pull-down node of the gate driving circuit.

[0022] In a possible embodiment, the carrier mobility of the channel region of the first active layer is not lower than a preset carrier mobility threshold value;

[0023] The carrier mobility of the channel region of the second active layer is not higher than the preset carrier mobility threshold value;

[0024] The preset carrier mobility threshold value is 15-30 cm 2 Vs.

[0025] In a possible embodiment, the first metal oxide TFT is at least part of the TFTs in a GOA circuit, the second metal oxide TFT is a switching TFT in a display area, and the at least part of the TFTs comprises a driving TFT for controlling the output of a signal.

[0026] The embodiment of the present application has the following beneficial effects:

[0027] The metal oxide thin film transistor backboard provided by the embodiment of the present application can be used to design the circuit of the GOA area and the AA area by setting the metal oxide TFT with different active layers on the metal oxide TFT backboard, so that the user can select different metal oxide TFTs according to actual needs, and the first metal oxide TFT can be selected as the TFT with high requirements on the mobility in the designed circuit, and the second metal oxide TFT can be selected as the TFT with high requirements on stability in the designed circuit, so that the designed circuit has relatively high mobility under the condition of meeting the performance requirements, that is, the embodiment is selected to make the metal oxide TFT backboard have high performance and high stability at the same time.

[0028] Of course, implementing any product or method of the present application does not necessarily require all the advantages described above. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other embodiments can also be obtained by those skilled in the art based on these drawings.

[0030] Figure 1 The circuit schematic diagram of the GOA circuit of the metal oxide TFT backboard provided by the embodiment of the present application;

[0031] Figure 2 The structure schematic diagram of the metal oxide TFT backboard provided by the embodiment of the present application;

[0032] Figure 3 The structure schematic diagram of the metal oxide TFT backboard provided by the embodiment of the present application;

[0033] Figure 4 The structure schematic diagram of the metal oxide TFT backboard provided by the embodiment of the present application;

[0034] Figure 5 The structure schematic diagram of the metal oxide TFT backboard provided by the embodiment of the present application;

[0035] Figure 6a The structure schematic diagram of the metal oxide thin film stack provided by the embodiment of the present application;

[0036] Figure 6b The structure schematic diagram of the metal oxide thin film stack provided by the embodiment of the present application;

[0037] Figure 6cAnother schematic view of the metal oxide thin film stack provided by the embodiments of the present application is shown in FIG. 6.

[0038] Figure 7 A flowchart of a method for preparing a metal oxide TFT backplane provided by the embodiments of the present application is shown in FIG. 7.

[0039] Figure 8a A structure diagram of an intermediate product in a preparation process of a method for preparing a metal oxide TFT backplane provided by the embodiments of the present application is shown in FIG. 8.

[0040] Figure 8b Another structure diagram of an intermediate product in a preparation process of a method for preparing a metal oxide TFT backplane provided by the embodiments of the present application is shown in FIG. 9.

[0041] Figure 8c Another structure diagram of an intermediate product in a preparation process of a method for preparing a metal oxide TFT backplane provided by the embodiments of the present application is shown in FIG. 10.

[0042] Figure 8d A structure diagram of a metal oxide TFT backplane prepared by a method for preparing a metal oxide TFT backplane provided by the embodiments of the present application is shown in FIG. 11. DETAILED DESCRIPTION

[0043] 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 some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art based on the present application are within the scope of protection of the present application.

[0044] In order to more clearly describe the metal oxide TFT backplane provided by the embodiments of the present application, a possible application scenario of the metal oxide TFT backplane provided by the embodiments of the present application will be described below by way of example. It can be understood that the following example is only one possible application scenario of the metal oxide thin film transistor TFT backplane provided by the embodiments of the present application.

[0045] Referring to FIG. 12, Figure 1 , Figure 1 A GOA circuit schematic diagram of a metal oxide TFT backplane provided by the embodiments of the present application is shown in FIG. 12. As shown in FIG. 12, Figure 1M1-3, M5-7, M10-13, M16 are 11 TFTs. It can be understood that, in order to improve the performance of the metal oxide TFT backplane to achieve high resolution, high refresh rate, low power consumption, narrow frame and other high-performance display requirements, it is necessary to improve the input and output capability of the TFT backplane, and therefore in a possible embodiment, M1-3, M5-7, M10-13, M16 are high mobility TFTs, wherein high mobility refers to a mobility higher than a preset mobility threshold, and the preset mobility threshold can be different according to different application scenarios, for example, the preset mobility threshold has a value range of 15-20 cm 2 Vs (square centimeter per volt second).

[0046] However, if M1-3, M5-7, M10-13, M16 are all high mobility TFTs, M6, M16, M10 will be affected by a high voltage pulse due to the effect of the drain under the strong voltage of VDD and PU, and the peak value of the high voltage pulse is high, resulting in damage to M6 (including M6A and M6B), M16 (including M16A and M16B), and M10 (including M10A and M10B).

[0047] It can be seen that if M1-3, M5-7, M10-13, M16 are all high mobility TFTs, the metal oxide TFTs in the metal oxide TFT backplane are prone to damage during operation, which further leads to the failure of the metal oxide TFT backplane to work normally, i.e., the stability of the metal oxide TFT backplane is poor.

[0048] Based on this, an embodiment of the present application provides a TFT backplane with multiple mobilities, as shown in Figure 2 As shown, the TFT backplane includes a first metal oxide TFT 210 and a second metal oxide TFT 220.

[0049] The first metal oxide TFT 210 includes a first active layer 211 with a first mobility, and the first active layer 211 contains a first metal oxide thin film 231.

[0050] The second metal oxide TFT 220 includes a second active layer 221 with a second mobility, and the second active layer 221 contains a second metal oxide thin film 232, and the second mobility is less than the first mobility.

[0051] With the embodiment, the metal oxide TFT backplane can be used to design the circuit of the GOA area and the AA area according to actual needs by setting the metal oxide TFTs with different active layers on the metal oxide TFT backplane. For the TFTs with high requirements on the mobility in the designed circuit, the first metal oxide TFTs can be selected as the TFTs. For the TFTs with high requirements on the stability in the designed circuit, the second metal oxide TFTs can be selected as the TFTs. Thus, the designed circuit has relatively high mobility while meeting the performance requirements, i.e., the metal oxide TFT backplane has both high performance and high stability.

[0052] For example, still taking the circuit shown in the foregoing Figure 1 As an example, still taking the circuit shown in the foregoing

[0053] For example, still taking the circuit shown in the foregoing

[0054] In addition, the metal oxide TFT backplane can further include other metal oxide TFTs in addition to the first metal oxide TFT 210 and the second metal oxide TFT 220, and the active layer of the other metal oxide TFTs can have a mobility of the first mobility, the second mobility, or a mobility other than the first mobility and the second mobility. For example, in one possible embodiment, the metal oxide TFT backplane can further include a third metal oxide TFT, and the third metal oxide TFT can include a third active layer having a third mobility, the third mobility being different from the first mobility and the second mobility. The third mobility can be less than the second mobility, greater than the first mobility, or both.

[0055] If the metal oxide TFT backplane includes only the first metal oxide TFT 210 and the second metal oxide TFT 220, the first mobility can be any high mobility, i.e., the first mobility should be greater than a preset mobility threshold. The second mobility can be any non-high mobility, i.e., the second mobility should be less than the preset mobility threshold. For example, the preset mobility threshold can be 30 cm 2 / Vs, the first mobility can be 40 cm 2 / Vs, the first mobility can be 40 cm 2 / Vs, the first mobility can be 40 cm 2 / Vs, the second mobility can be 28 cm 2 / Vs, the second mobility can be 28 cm 2 / Vs, the second mobility can be 28 cm 2 / Vs, the second mobility can be 28 cm

[0056] If the metal oxide TFT backplane further includes other metal oxide TFTs in addition to the first metal oxide TFT 210 and the second metal oxide TFT 220, and the active layer of the other metal oxide TFTs has a mobility greater than the first mobility, the first mobility can be not greater than the preset mobility threshold. In addition, if the metal oxide TFT backplane further includes other metal oxide TFTs in addition to the first metal oxide TFT 210 and the second metal oxide TFT 220, and the active layer of the other metal oxide TFTs has a mobility less than the second mobility, the second mobility can be not less than the preset mobility threshold.

[0057] However, in theory, the active layer of at least one metal oxide TFT included in the metal oxide TFT backplane should have a mobility greater than the preset mobility threshold, and the active layer of at least one metal oxide TFT included in the metal oxide TFT backplane should have a mobility less than the preset mobility threshold.

[0058] For the convenience of description, only the case that the TFT backplane only includes the first metal oxide TFT 210 and the second metal oxide TFT 220 is described below, and the principle is the same for the case that the TFT backplane also includes other TFTs, and thus is not described herein.

[0059] In order to more clearly describe the metal oxide TFT backplane provided by the embodiments of the present application, the structure of the first active layer 211 and the second active layer 221 will be described below.

[0060] The first active layer 211 includes the first metal oxide film 231, and the second active layer is composed of the second metal oxide film 232.

[0061] In a possible embodiment, the first metal oxide film 231 is at least one metal oxide semiconductor layer, and the second metal oxide film is at least one metal oxide semiconductor layer. For example, the first metal oxide film 231 is one metal oxide semiconductor layer, and the second metal oxide film 232 is also one metal oxide semiconductor layer. For another example, the first metal oxide film 231 is two metal oxide semiconductor layers, and the second metal oxide film 232 is one metal oxide semiconductor layer. The number of metal oxide semiconductor layers in the first metal oxide film 231 can also be three or more, and the number of metal oxide semiconductor layers in the second metal oxide film 232 can also be two or more, and the present embodiment does not make any limitation on this.

[0062] In this example, the carrier mobility of the channel region of the first active layer 211 is not less than a preset carrier mobility threshold, the carrier mobility of the channel region of the second active layer 221 is not less than the preset carrier threshold, and the carrier mobility of the channel region of the second active layer 221 is not higher than the preset carrier mobility threshold. Among them, the preset carrier mobility threshold belongs to 15-30 cm 2 / Vs.

[0063] It can be understood that the mobility of the active layer is positively correlated with the carrier mobility of the channel region. Since the carrier mobility of the channel region of the first active layer 211 is higher than the carrier mobility of the channel region of the second active layer 221, the mobility of the first active layer 211 is higher than the mobility of the second active layer 221.

[0064] The first active layer 211 including the first metal oxide film 231 can mean that the first active layer 211 includes the first metal oxide film 231 in the channel region of the first active layer 211, and the second active layer 221 including the second metal oxide film 232 can mean that the second active layer 221 includes the second metal oxide film 232 in the channel region of the second active layer 221. Figure 4The diagram shows only the first metal oxide film 231, meaning the first active layer 211 is composed of a single layer of the first metal oxide film 231. Alternatively, it could mean that the first active layer 211 includes the first metal oxide film 231 and other metal oxide films besides the first metal oxide film 231, for example, such as... Figure 2 , 3 As shown, the first active layer 211 may be composed of a first metal oxide thin film 231 and a second metal oxide thin film 232.

[0065] The second active layer 221 is composed of a second metal oxide thin film 232, meaning that the second active layer 221 includes only the second metal oxide thin film 232 and does not include any other metal oxide thin films besides the second metal oxide thin film 232. Furthermore, the second active layer 221 may include only one layer of the second metal oxide thin film 232, or it may include multiple layers of the second metal oxide thin film 232. If the second active layer 221 includes only one layer of the second metal oxide thin film 232, then the first active layer 211 may include only one layer of the first metal oxide thin film 231, or it may include multiple layers of metal oxide thin films, with at least one layer of the first metal oxide thin film 231 present in each of the multiple layers. If the second active layer 221 includes n layers of the second metal oxide thin film 232, then the first active layer 211 should include at least n layers of metal oxide thin films, and at least one layer of the first metal oxide thin film 231 present in each of the n layers.

[0066] By using this embodiment, the mobility of the first active layer 211 can be made higher than that of the second active layer 221 in a relatively simple way.

[0067] As explained above, the number of metal oxide thin films in the first active layer 211 can be equal to or greater than the number of metal oxide thin films in the second active layer 221.

[0068] The following will explain these two cases separately, specifically the case where the number of metal oxide thin films in the first active layer 211 is equal to the number of metal oxide thin films in the second active layer 221.

[0069] like Figure 4 As shown, in one possible embodiment, the first active layer 211 is composed of a single-layer first metal oxide film 231, and the second active layer is composed of a single-layer second metal oxide film 232. In this embodiment, the second metal oxide film 232 contains IGZO, and the first metal oxide film 221 has a mobility of 12-20 cm⁻¹. 2 Metal oxide semiconductor materials with a value of / Vs or higher are formed.

[0070] In the case where the first active layer 211 is composed of a single layer of the first metal oxide film 231, it means that the first active layer 211 includes only one layer of metal oxide film, and the one layer of metal oxide film is the first metal oxide film 231. Similarly, in the case where the second active layer 221 is composed of a single layer of the second metal oxide film, it means that the second active layer 221 includes only one layer of metal oxide film, and the one layer of metal oxide film is the second metal oxide film 232.

[0071] In the case where the number of layers of the metal oxide film in the first active layer 211 is greater than the number of layers of the metal oxide film in the second active layer 221, the first active layer 211 can be composed of a plurality of layers of metal oxide film, and the second active layer 221 can be composed of a single layer of metal oxide film. Figure 2 Or Figure 4 Figure 5 As shown in FIGS. 5, 6, and 7, the first active layer 211 can be composed of a plurality of layers of metal oxide film, and the second active layer 221 can be composed of a single layer of metal oxide film. The metal oxide film in the second active layer 221 can be the same layer of metal oxide film as one of the plurality of layers of metal oxide film in the first active layer 211. Figure 2 4 As shown in FIGS. 5, 6, and 7, the first active layer 211 can be composed of a plurality of layers of metal oxide film, and the second active layer 221 can be composed of a single layer of metal oxide film. The metal oxide film in the second active layer 221 can be the same layer of metal oxide film as one of the plurality of layers of metal oxide film in the first active layer 211.

[0072] The plurality of layers of metal oxide film in the first active layer 211 can include the first metal oxide film 231 and the second metal oxide film 232, and the plurality of layers of metal oxide film can include only the first metal oxide film 231 and the second metal oxide film 232, and not include any other metal oxide film other than the first metal oxide film 231 and the second metal oxide film 232.

[0073] The plurality of layers of metal oxide film can be two layers of metal oxide film, or three or more layers of metal oxide film. For the sake of convenience in description, only the cases where the plurality of layers of metal oxide film are two layers of metal oxide film and three layers of metal oxide film are described below. The principles are the same for the case where the plurality of layers of metal oxide film are four or more layers of metal oxide film, and thus are not described again.

[0074] In the case where the plurality of layers of metal oxide film are two layers of metal oxide film, the first active layer 211 can be composed of one layer of the first metal oxide film 231 and one layer of the second metal oxide film 232. In the case where the plurality of layers of metal oxide film are three layers of metal oxide film, the first active layer 211 can be composed of one layer of the first metal oxide film 231 and two layers of the second metal oxide film 232, or two layers of the first metal oxide film 231 and one layer of the second metal oxide film 232.

[0075] ​​The first metal oxide constituting the first active layer and the second metal oxide constituting the second active layer are different. For example, in a possible embodiment, the first metal oxide is a metal oxide composed of at least two metals selected from indium, gallium, zinc, tin, tungsten, tantalum, and lanthanide elements, and the second metal oxide is a metal oxide composed of at least two metals selected from indium, gallium, and zinc. In addition, the first metal oxide and the second metal oxide are different.

[0076] For example, in a possible embodiment, the first metal oxide is IGTO, and the second metal oxide is Pr-IGZO. It can be understood that, due to the electrical properties of IGTO and Pr-IGZO, the mobility of the first active layer 211 prepared from IGTO is higher than the mobility of the second active layer 221 prepared from Pr-IGZO.

[0077] The stacking manner between different metal oxide thin films can be different according to different application scenarios. For example, for the convenience of description, only the case of stacking the second metal oxide thin film 232 on the first metal oxide thin film 231 is taken as an example. In a possible embodiment, the side surface of the second metal oxide thin film 232 is coplanar with the side surface of the first metal oxide thin film 231, and the first contact surface of the first metal oxide thin film 231 in contact with the second metal oxide thin film and the second contact surface of the second metal oxide thin film 232 in contact with the first metal oxide thin film 231 are coincident, for example, as shown in FIG. 2B. Figure 6a

[0078] In another possible embodiment, the side surface of the second metal oxide thin film 232 is parallel to but not coplanar with the side surface of the first metal oxide thin film 231, and the second contact surface is a sub-region of the first contact surface, for example, as shown in FIG. 2C. Figure 6b Figure 6c In yet another possible embodiment, the second metal oxide thin film 232 wraps the first metal oxide thin film 231, for example, as shown in FIG. 2D.

[0079] In a possible embodiment, the second metal oxide TFT 220 is a high-stability TFT in the TFT backplane, where the high-stability TFT is a TFT with a required stability higher than a preset stability threshold, and the first metal oxide TFT 210 is a TFT other than the high-stability TFT in the TFT backplane, and the stability of the first metal oxide TFT is not lower than the preset stability threshold.

[0080] ​​Depending on the application scenario, stability can be expressed in different forms, including but not limited to any one of PBTS, NBTIS, high voltage withstand capability, and high current withstand capability, or a combination of multiple forms. For ease of description, the following explanation only uses stability expressed in the form of PBTS as an example. The principle is the same for cases where stability is expressed in other forms, and this embodiment does not impose any restrictions on them.

[0081] For example, suppose stability is expressed in the form of PBTS(1h)ΔVth, and suppose the stability of the second metal oxide TFT 220 is PBTS(1h)ΔVth < 2V, and the stability of the first metal oxide TFT 210 is PBTS(1h)ΔVth < 4V. Furthermore, suppose the preset stability threshold is PBTS(1h)ΔVth < 5V. If the stability requirement for a TFT in the circuit designed by the user for the TFT backplane is PBTS(1h)ΔVth < 4.5V, then the second metal oxide TFT is selected as that TFT. If the stability requirement for a TFT in the circuit designed by the user for the TFT backplane is PBTS(1h)ΔVth < 6V, then the first metal oxide TFT is selected as that TFT.

[0082] In this embodiment, a second metal oxide TFT is used as a high-stability TFT to prioritize meeting the stability requirements of each TFT in the TFT backplane, thereby further improving the stability of the TFT backplane.

[0083] Taking the first and second metal oxide TFTs as TFTs in the gate driving circuit as an example, the driving TFT that controls the output signal of the gate driving circuit requires high mobility, while the switching TFT that controls the pull-down node of the gate driving circuit requires high stability. Therefore, in this example, the first metal oxide TFT 210 is the driving TFT that controls the output signal of the gate driving circuit, and the second metal oxide TFT is the switching TFT that controls the pull-down node of the gate driving circuit.

[0084] Using the first and second metal oxide TFTs as TFTs in the GOA circuit and the display area circuit, some TFTs in the GOA circuit, such as the driving TFT for control signal output, have high mobility requirements, while the switching TFTs in the display area have high stability requirements. Therefore, in this example, the first metal oxide TFT is at least a portion of the TFTs in the GOA circuit, and the second metal oxide TFT is the switching TFT in the display area, with at least a portion of the TFTs including the driving TFT for control signal output.

[0085] This invention also provides a method for fabricating a metal oxide TFT backplane, comprising:

[0086] A first metal oxide TFT 210 and a second metal oxide TFT 220 are disposed on the same substrate to obtain a metal oxide TFT backplane. The first metal oxide TFT 210 includes a first active layer 211 having a first mobility, and the second metal oxide TFT 220 includes a second active layer 221 having a second mobility. The first active layer 211 includes a first metal oxide thin film 231, and the second active layer 221 includes a second metal oxide thin film 232. The second mobility is less than the first mobility.

[0087] By using this embodiment, active layers of metal oxide TFTs with different mobility can be formed on the metal oxide TFT backplane. This allows users to select different metal oxide TFTs for the design of circuits in the GOA and AA regions according to actual needs. For TFTs with high mobility requirements in the designed circuit, the first metal oxide TFT can be selected as the TFT. For TFTs with high stability requirements in the designed circuit, the second metal oxide TFT can be selected as the TFT. This allows the designed circuit to have a relatively high mobility while meeting performance requirements. In other words, by using this embodiment, the metal oxide TFT backplane can simultaneously achieve high performance and high stability.

[0088] To more clearly illustrate the method for fabricating a TFT backplane with multiple mobility provided in the embodiments of the present invention, the method will be described in detail below. (See also: [link to relevant documentation]). Figure 7 , Figure 7 The diagram shown is a flowchart illustrating a method for fabricating a TFT backplane with multiple mobility parameters according to an embodiment of the present invention, which may include:

[0089] S701 has multiple gates and gate insulating layers disposed on the same substrate.

[0090] The plurality of gates includes a first gate belonging to a first metal-oxide-semiconductor TFT and a second gate belonging to a second metal-oxide-semiconductor TFT. The resulting product can be as follows: Figure 8a As shown. It is understandable that... Figure 7 , Figure 8a - Figure 8d This is merely a schematic diagram of the metal oxide TFT backplane fabrication method provided in this embodiment of the invention. Figure 7 , Figure 8a - Figure 8d The illustrated process is for fabricating a bottom-gate structure metal oxide TFT backplane. In other possible embodiments, the metal oxide TFT backplane provided in this invention can also be a top-gate structure, for example, as shown below. Figure 5As shown. The fabrication principle for the backplane of a top-gate metal oxide TFT is the same, so it will not be described again here.

[0091] S702, a first active layer is provided in a first region on the side of the gate insulating layer away from the substrate, and a second active layer is provided in a second region on the side of the gate insulating layer away from the substrate.

[0092] In this configuration, the orthographic projection of each first region onto the substrate is located within the first gate, and the orthographic projection of each second region onto the substrate is located within the second gate.

[0093] The orthographic projection of the first region onto the substrate refers to the projection of the first region onto the normal direction of the substrate plane, which is the plane on which the substrate lies. Similarly, the orthographic projection of the second region onto the substrate refers to the projection of the second region onto the normal direction of the substrate plane. At this point, the obtained product can be as follows: Figure 8c As shown.

[0094] S703 sets source and drain for each first active layer and second active layer respectively.

[0095] S704, a passivation layer is deposited on a substrate having multiple gates, gate insulating layers, a first active layer, a second active layer, a source, and a drain to obtain a TFT backplane with multiple mobility.

[0096] At this point, the product obtained can be as follows: Figure 8d As shown.

[0097] The following will explain how to set the first active layer and the second active layer. In one possible embodiment, a metal oxide may be disposed on the side of the gate insulating layer away from the substrate, and different etching methods may be used to etch the first region and the second region respectively, so as to form the first active layer in the first region and the second active layer in the second region.

[0098] For example, the structure of the first active layer and the second active layer is as described above. Figure 3 As shown, a first metal oxide can be formed on the side of the gate insulating layer away from the substrate. This first metal oxide is an oxide constituting a first metal oxide thin film. The first metal oxide is etched to retain the first metal oxide in the first region, and the metal oxides outside the first region are etched away, thereby forming a first metal oxide thin film in the first region. The product at this point is as follows: Figure 8b As shown.

[0099] A second metal oxide is disposed on the side of the gate insulating layer away from the substrate. This second metal oxide is an oxide constituting the second metal oxide thin film. The second metal oxide is etched to retain the second metal oxide in the first and second regions, and the metal oxides other than those in the first and second regions are etched, thereby forming a first metal oxide thin film in the first region. At this time, the product is as follows: Figure 8b As shown.

[0100] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0101] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0102] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. Related parts can be found in the descriptions of the method embodiments.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A metal oxide thin-film transistor (TFT) backplane, characterized in that, The metal oxide TFT backplane includes: A first metal-oxide-semiconductor (MODS) TFT and a second MODS TFT; the first MODS TFT and the second MODS TFT are TFTs in a gate driving circuit, the first MODS TFT includes M1, M3, and M13; the second MODS TFT includes M6A, M6B, M16A, and M16B; M1 is configured to receive an input signal, and M3 and M13 are configured to output signals; the gates of M6A and M6B are connected to pull-up points PU, the drains of M6A and M16A are connected to the power supply signal VDDA; the drains of M6B and M16B are connected to the power supply signal VDDB; The first metal oxide TFT includes a first active layer having a first mobility, the first active layer comprising a first metal oxide thin film; The second metal oxide TFT includes a second active layer having a second mobility, the second active layer comprising a second metal oxide thin film, and the second mobility being less than the first mobility.

2. The metal oxide TFT backplane according to claim 1, characterized in that, The difference between the first mobility and the second mobility is at least 10.

3. The TFT backplane according to claim 1, characterized in that, The first metal oxide thin film is at least one metal oxide semiconductor layer; The second metal oxide thin film is at least one metal oxide semiconductor layer.

4. The TFT backplane according to claim 1, characterized in that, The first active layer is composed of a single-layer first metal oxide thin film; The second active layer is composed of a single-layer second metal oxide thin film; The second metal oxide film comprises IGZO; The first metal oxide film has a mobility of 15-20 cm⁻¹ 2 Metal oxide semiconductor materials with a value of / Vs or higher are formed.

5. The TFT backplane according to claim 1, characterized in that, The first active layer is composed of multiple metal oxide thin film stacks; The second active layer is composed of a single-layer metal oxide thin film; The second active layer is a metal oxide film and one of the plurality of metal oxide films are patterned to be the same metal oxide film layer.

6. The TFT backplane according to any one of claims 1-5, characterized in that, The first active layer comprises a metal oxide composed of at least two metals selected from indium, gallium, zinc, tin, tungsten, tantalum, and lanthanides; The second active layer comprises a metal oxide composed of at least two metals selected from indium, gallium, and zinc.

7. The TFT backplane according to claim 1, characterized in that, The carrier mobility of the first active layer channel region is not lower than a preset carrier mobility threshold. The carrier mobility in the channel region of the second active layer is not higher than the preset carrier mobility threshold. The preset carrier mobility threshold is between 15-30 cm. 2 / Vs.

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