Tft substrate, method for manufacturing the same, display panel, and display device

Abstract

The application relates to a TFT substrate, a preparation method thereof, a display panel and a display device. The TFT substrate comprises a display area and a driving area, the driving area is used for driving the display area to display, and the device mobility of the driving area is higher than that of the display area. In the application, the TFT substrate comprises the display area and the driving area, the device mobility of the driving area is set to be higher than that of the display area, the device mobility of the driving area is improved, the device stability of the driving area is improved, the possibility of threshold voltage offset of the driving circuit caused by the influence of the external environment on the driving area is reduced, the driving capacity of the driving circuit is improved, and the display stability of the display panel is improved.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to TFT substrates and their preparation methods, display panels and display devices. Background Technology

[0002] Low-temperature polycrystalline oxide (LTPO) display technology combines two types of thin-film transistors, low-temperature polycrystalline silicon (LTPS) and indium gallium zinc oxide (IGZO), thus enabling display panels to have both strong driving capabilities and low power consumption. It is suitable for both high-frequency and low-frequency displays and has become an increasingly popular technology in display panels.

[0003] Currently, existing LTPO panels have an oxide semiconductor layer in the display area, which is typically deposited directly by PVD and has an amorphous structure. The driving circuit area of ​​the LTPO panel has a low-temperature polycrystalline silicon semiconductor layer, which is also an amorphous structure. It can be seen that both the display area and the driving circuit area of ​​the LTPO panel have amorphous semiconductor layers. Due to the poor device stability of semiconductor layers, especially under external light (such as ambient light or backlight) or thermal stimulation (such as high temperatures in summer), the threshold voltage (Vth) of the driving circuit is prone to shift, thus affecting the driving capability of the driving circuit and the display stability of the display panel. Summary of the Invention

[0004] Therefore, it is necessary to address the problem that the driving circuit area devices of existing LTPO panels have poor stability and are prone to threshold voltage shift due to external environmental influences, thereby affecting the display stability of the display panel. To address this issue, a TFT substrate, its fabrication method, a display panel, and a display device are provided.

[0005] To achieve the above objectives, in one aspect, embodiments of this application provide a TFT substrate, the TFT substrate comprising:

[0006] Display area; and

[0007] A driving area is used to drive the display area to perform display.

[0008] The device mobility of the driving area is higher than that of the display area.

[0009] Optionally, the display area includes a first amorphous layer, the driving area includes a crystalline layer, and the device mobility of the crystalline layer is higher than that of the first amorphous layer.

[0010] Optionally, the driving region further includes a second amorphous layer, which is stacked with the crystalline layer.

[0011] Optionally, the first amorphous layer and the second amorphous layer are amorphous oxide semiconductor layers, and the crystalline layer is a crystalline oxide semiconductor layer.

[0012] Optionally, the driving region further includes an insulating layer and a protective layer, with the crystalline layer disposed between the insulating layer and the protective layer.

[0013] Optionally, the first amorphous layer is disposed between the insulating layer and the protective layer.

[0014] On the other hand, this application also provides a method for preparing a TFT substrate, wherein the TFT substrate is any of the TFT substrates described above, and the preparation method includes the following steps:

[0015] An insulating layer is formed on the substrate;

[0016] A first amorphous layer and a second amorphous layer are formed on the insulating layer;

[0017] A third amorphous layer is formed on the second amorphous layer;

[0018] The third amorphous layer is heated or irradiated with a laser to form a crystalline layer;

[0019] A protective layer is formed on the crystalline layer and the first amorphous layer.

[0020] On the other hand, this application also provides a method for preparing a TFT substrate, wherein the TFT substrate is any of the TFT substrates described above, and the preparation method includes the following steps:

[0021] An insulating layer is formed on the substrate;

[0022] A first amorphous layer and a third amorphous layer are formed on the insulating layer;

[0023] The third amorphous layer is heated or irradiated with a laser to form a crystalline layer;

[0024] A protective layer is formed on the crystalline layer and the first amorphous layer.

[0025] On the other hand, embodiments of this application also provide a display panel, including any of the TFT substrates described above.

[0026] On the other hand, embodiments of this application also provide a display device, including any of the display panels described above.

[0027] One of the above technical solutions has the following advantages and beneficial effects:

[0028] This application provides a TFT substrate and its preparation method, a display panel, and a display device. The TFT substrate includes a display area and a driving area, and the device mobility of the driving area is higher than that of the display area. Increasing the device mobility of the driving area can improve the device stability of the driving area, reduce the possibility of threshold voltage shift of the driving circuit due to external environmental influences, improve the driving capability of the driving circuit, and thus improve the display stability of the display panel. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a TFT substrate provided in an embodiment of this application.

[0030] Figure 2 for Figure 1 The diagram shows a cross-sectional view of the TFT substrate.

[0031] Figure 3 This is a cross-sectional schematic diagram of another TFT substrate provided in an embodiment of this application.

[0032] Figure 4 A flowchart illustrating a method for fabricating a TFT substrate according to an embodiment of this application.

[0033] Figure 5 This is a cross-sectional schematic diagram of each layer formed on the base layer to complete steps S4 to S6 of the embodiments of this application.

[0034] Figure 6 A flowchart illustrating another method for fabricating a TFT substrate provided in this application embodiment.

[0035] Figure 7 This is a cross-sectional schematic diagram of each layer formed on the substrate layer to complete steps S03 to S05 of the embodiments of this application. Detailed Implementation

[0036] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0037] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to and integrated with the other element, or there may be an intervening element present. The terms "layered," "one side," "the other side," and similar expressions used herein are for illustrative purposes only. Furthermore, the use of terms such as "first" and "second" in this application does not indicate any order, quantity, or importance, but is merely used to distinguish different parts.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] Currently, existing LTPO panels have an oxide semiconductor layer in the display area, which is typically deposited directly by PVD and has an amorphous structure. The driving circuit area of ​​the LTPO panel has a low-temperature polycrystalline silicon semiconductor layer, which is also an amorphous structure. It can be seen that both the display area and the driving circuit area of ​​the LTPO panel have amorphous semiconductor layers. Due to the poor device stability of semiconductor layers, especially under external light (such as ambient light or backlight) or thermal stimulation (such as high temperatures in summer), the threshold voltage (Vth) of the driving circuit is prone to shift, thus affecting the driving capability of the driving circuit and the display stability.

[0040] To address the aforementioned problems, this application provides a TFT substrate and its fabrication method, a display panel, and a display device, which will be described below in conjunction with the accompanying drawings. For example, please refer to... Figure 1 , Figure 1 This is a schematic diagram of the structure of a TFT substrate provided in an embodiment of this application. The TFT substrate includes a display area 200 and a driving area 100. The driving area 100 is used to drive the display area 200 for display, wherein the device mobility of the driving area 100 is higher than that of the display area 200.

[0041] In this embodiment, the TFT substrate includes a display area 200 and a driving area 100, and the device mobility of the driving area 100 is set to be higher than that of the display area 200. Increasing the device mobility of the driving area 100 can improve the device stability of the driving area 100, reduce the possibility of threshold voltage deviation of the driving circuit caused by the influence of the external environment, improve the driving capability of the driving circuit, and thus improve the display stability of the display panel.

[0042] Examples such as Figure 2 As shown, Figure 2This is a cross-sectional schematic diagram of a TFT substrate provided in an embodiment of this application. The display area 200 includes a first amorphous layer 210, and the driving area 100 includes a crystalline layer 110. The device mobility of the crystalline layer 110 is higher than that of the first amorphous layer 210. In this application, a crystalline layer 110 is provided in the driving area 100. Since the device mobility of the crystalline layer 110 is higher than that of the first amorphous layer 210, the device mobility of the driving area 100 can be higher than that of the display area 200. In this application, the device mobility is the device carrier mobility.

[0043] For example, the first amorphous layer 210 is an amorphous oxide semiconductor layer, and the crystalline layer 110 is a crystalline oxide semiconductor layer. In this application, the crystalline layer 110 can be formed by heating or laser irradiation of an amorphous oxide layer. Figure 2 As shown, the driving region 100 further includes a base layer 190, a first metal layer 150 (M1), an insulating layer 130 (GI), a second metal layer 160 (M2), and a protective layer 140 (PV). The base layer 190, first metal layer 150, insulating layer 130, crystalline layer 110, second metal layer 160, and protective layer 140 are sequentially arranged along a first direction, which is... Figure 2 The direction is from bottom to top. With this arrangement, the crystalline layer 110 is positioned between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the crystalline layer 110. In this application, the substrate layer 190 can be a glass substrate layer 190, but other types of substrate layers 190 can also be selected; there is no limitation here.

[0044] In such Figure 2 As shown, the display area 200 further includes a third metal layer 220 and a fourth metal layer 230, wherein the base layer 190, the third metal layer 220 (M1), the insulating layer 130, the first amorphous layer 210 (M2), the fourth metal layer 230, and the protective layer 140 are sequentially arranged along a first direction. With this arrangement, the first amorphous layer 210 is disposed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the first amorphous layer 210.

[0045] The above-mentioned TFT substrate fabrication method is as follows: First, a first metal layer 150 and a third metal layer 220 are fabricated on a substrate layer 190; then, an insulating layer 130 is fabricated on the side of the first metal layer 150 and the third metal layer 220 facing away from the substrate layer 190; next, a first amorphous layer 210 and a third amorphous layer 111 are fabricated on the side of the insulating layer 130 facing away from the first metal layer 150 and the third metal layer 220; then, the third amorphous layer 111 is heated or irradiated with a laser to form a crystalline layer 110; then, a second metal layer 160 is formed on the side of the crystalline layer 110 facing away from the insulating layer 130, and a fourth metal layer 230 is formed on the side of the first amorphous layer 210 facing away from the insulating layer 130; finally, a protective layer 140 is fabricated on the side of the second metal layer 160 and the fourth metal layer 230 facing away from the insulating layer 130. The aforementioned third amorphous layer 111 is an amorphous oxide semiconductor layer.

[0046] Examples such as Figure 3 As shown, Figure 3 This is a cross-sectional schematic diagram of another TFT substrate provided in an embodiment of this application. The driving region 100 further includes a second amorphous layer 120, which is stacked with a crystalline layer 110. This arrangement forms a structure where the second amorphous layer 120 and the crystalline layer 110 are stacked. On the one hand, the second amorphous layer 120 can improve the film uniformity, and on the other hand, the crystalline layer 110 can improve the device mobility. The second amorphous layer 120 is an amorphous oxide semiconductor layer.

[0047] like Figure 3 As shown, the driving region 100 further includes a base layer 190, a first metal layer 150, an insulating layer 130, a second metal layer 160, and a protective layer 140. The base layer 190, the first metal layer 150, the insulating layer 130, the second amorphous layer 120, the crystalline layer 110, the second metal layer 160, and the protective layer 140 are sequentially arranged along a first direction, which is... Figure 3 The direction is from bottom to top. With this arrangement, the crystalline layer 110 is placed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the crystalline layer 110.

[0048] In such Figure 3 As shown, the display area 200 further includes a third metal layer 220 and a fourth metal layer 230, wherein the base layer 190, the third metal layer 220, the insulating layer 130, the first amorphous layer 210, the fourth metal layer 230, and the protective layer 140 are sequentially arranged along a first direction. With this arrangement, the first amorphous layer 210 is disposed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the first amorphous layer 210.

[0049] The above-mentioned TFT substrate fabrication method is as follows: First, a first metal layer 150 and a third metal layer 220 are fabricated on a substrate layer 190; then, an insulating layer 130 is fabricated on the side of the first metal layer 150 and the third metal layer 220 facing away from the substrate layer 190; then, a first amorphous layer 210 and a second amorphous layer 120 are fabricated on the side of the insulating layer 130 facing away from the first metal layer 150 and the third metal layer 220; then, a third amorphous layer 111 is fabricated on the side of the second amorphous layer 120 facing away from the insulating layer 130; then, the third amorphous layer 111 is heated or irradiated with a laser to form a crystalline layer; then, a second metal layer 160 is formed on the side of the crystalline layer facing away from the insulating layer 130, and a fourth metal layer 230 is formed on the side of the first amorphous layer 210 facing away from the insulating layer 130; finally, a protective layer 140 is fabricated on the side of the second metal layer 160 and the fourth metal layer 230 facing away from the insulating layer 130. The aforementioned third amorphous layer 111 is an amorphous oxide semiconductor layer.

[0050] On the other hand, this application also provides a method for fabricating a TFT substrate, wherein the TFT substrate is any of the TFT substrates mentioned above. Please refer to [link to relevant documentation]. Figure 4 , Figure 4 This is a flowchart of a method for fabricating a TFT substrate according to an embodiment of the present disclosure. The method includes the following steps:

[0051] S1. An insulating layer 130 is formed on the substrate 190;

[0052] S2. A first amorphous layer 210 and a second amorphous layer 120 are formed on the insulating layer 130;

[0053] S3. A third amorphous layer 111 is formed on the second amorphous layer 120;

[0054] S4. Heat or irradiate the third amorphous layer 111 with a laser to form a crystalline layer;

[0055] S5. A protective layer 140 is formed on the crystalline layer and the first amorphous layer 210.

[0056] The TFT substrate prepared by the above method includes a display area 200 and a driving area 100. The display area 200 includes a first amorphous layer 210, and the driving area 100 includes a crystalline layer. The device mobility of the crystalline layer is higher than that of the first amorphous layer 210. Therefore, the device mobility of the driving area 100 is higher than that of the display area 200. Increasing the device mobility of the driving area 100 improves its device stability, reduces the possibility of threshold voltage shift in the driving circuit due to external environmental influences, and enhances the driving capability of the driving circuit, thereby improving the display stability of the display panel. Simultaneously, the TFT substrate prepared by the above method forms a structure where a second amorphous layer 120 and a crystalline layer are stacked. On the one hand, the second amorphous layer 120 improves film uniformity; on the other hand, the crystalline layer enhances device mobility.

[0057] The first amorphous layer 210, the second amorphous layer 120, and the third amorphous layer 111 are amorphous oxide semiconductor layers, and the crystalline layer is a crystalline oxide semiconductor layer. The first amorphous layer 210 and the second amorphous layer 120 can be made of the same material or different materials; the first amorphous layer 210 and the third amorphous layer 111 can be made of the same material or different materials; the second amorphous layer 120 and the third amorphous layer 111 can be made of the same material or different materials.

[0058] For example, step S1 in the above-described method for preparing a TFT substrate specifically includes the following steps:

[0059] S11. A first metal layer 150 and a third metal layer 220 are formed on the substrate layer 190;

[0060] S12, An insulating layer 130 is formed on the first metal layer 150 and the third metal layer 220.

[0061] Step S5 in the above-mentioned TFT substrate fabrication method specifically includes the following steps:

[0062] S51. A second metal layer 160 is formed on the crystalline layer, and a fourth metal layer 230 is formed on the first amorphous layer 210.

[0063] S52, A protective layer 140 is formed on the second metal layer 160 and the fourth metal layer 230.

[0064] The driving region 100 of the TFT substrate prepared according to the above preparation method includes a base layer 190, a first metal layer 150, an insulating layer 130, a second amorphous layer 120, a crystalline layer, a second metal layer 160, and a protective layer 140. The base layer 190, the first metal layer 150, the insulating layer 130, the second amorphous layer 120, the crystalline layer, the second metal layer 160, and the protective layer 140 are stacked sequentially. In this arrangement, the crystalline layer is disposed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the crystalline layer. The display area 200 in the TFT substrate includes a base layer 190, a third metal layer 220, an insulating layer 130, a first amorphous layer 210, a fourth metal layer 230, and a protective layer 140. The base layer 190, the third metal layer 220, the insulating layer 130, the first amorphous layer 210, the fourth metal layer 230, and the protective layer 140 are stacked sequentially. In this arrangement, the first amorphous layer 210 is disposed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the first amorphous layer 210.

[0065] In such Figure 3 As shown, the display area 200 further includes a third metal layer 220 and a fourth metal layer 230, wherein the base layer 190, the third metal layer 220, the insulating layer 130, the first amorphous layer 210, the fourth metal layer 230, and the protective layer 140 are sequentially arranged along a first direction. With this arrangement, the first amorphous layer 210 is disposed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the first amorphous layer 210.

[0066] Examples such as Figure 5 As shown, step S4 in the above-mentioned TFT substrate fabrication method specifically includes the following steps:

[0067] S41. A photoresist layer 170 is formed on the first amorphous layer 210 and the insulating layer 130, wherein the photoresist layer 170 does not cover the third amorphous layer 111.

[0068] S42. A seed layer 112 is formed on the third amorphous layer 111;

[0069] S43. The third amorphous layer 111 is heated or irradiated with a laser to form a crystalline layer.

[0070] In step S42 above, a seed layer 112 is formed on the third amorphous layer 111. During the heating or laser irradiation of the third amorphous layer, the seed layer 112 can control the grain size and crystallization rate. After the crystalline layer is formed, due to its excellent etching resistance, it can prevent channel damage during the subsequent formation of the second metal layer 160.

[0071] Examples such as Figure 5 As shown, the following steps are included after step S5 in the above-mentioned TFT substrate fabrication method:

[0072] S6. An organic film layer 180 is formed on the protective layer 140.

[0073] On the other hand, this application also provides a method for fabricating a TFT substrate, wherein the TFT substrate is any of the TFT substrates mentioned above. Please refer to [link to relevant documentation]. Figure 6 , Figure 6 This is a flowchart of another method for fabricating a TFT substrate according to an embodiment of the present disclosure. The method includes the following steps:

[0074] S01. An insulating layer 130 is formed on the substrate 190;

[0075] S02. A first amorphous layer 210 and a third amorphous layer 111 are formed on the insulating layer 130;

[0076] S03. The third amorphous layer 111 is heated or irradiated with a laser to form a crystalline layer;

[0077] S04. A protective layer 140 is formed on the crystalline layer and the first amorphous layer 210.

[0078] The TFT substrate prepared by the above method includes a display area 200 and a driving area 100. The display area 200 includes a first amorphous layer 210, and the driving area 100 includes a crystalline layer. The device mobility of the crystalline layer is higher than that of the first amorphous layer 210. Therefore, the device mobility of the driving area 100 is higher than that of the display area 200. Increasing the device mobility of the driving area 100 improves its device stability, reduces the possibility of threshold voltage shift in the driving circuit due to external environmental influences, and enhances the driving capability of the driving circuit, thereby improving the display stability of the display panel. The first amorphous layer 210 and the second amorphous layer 120 are amorphous oxide semiconductor layers, and the crystalline layer is a crystalline oxide semiconductor layer. The first amorphous layer 210 and the third amorphous layer 111 can be made of the same material or different materials.

[0079] For example, step S01 in the above-described method for preparing a TFT substrate specifically includes the following steps:

[0080] S011. A first metal layer 150 and a third metal layer 220 are formed on the substrate 190;

[0081] S012, An insulating layer 130 is formed on the first metal layer 150 and the third metal layer 220.

[0082] Step S04 in the above-mentioned TFT substrate fabrication method specifically includes the following steps:

[0083] S041. A second metal layer 160 is formed on the crystalline layer, and a fourth metal layer 230 is formed on the first amorphous layer 210.

[0084] S042, A protective layer 140 is formed on the second metal layer 160 and the fourth metal layer 230.

[0085] The driving region 100 in the TFT substrate prepared according to the above preparation method includes a base layer 190, a first metal layer 150, an insulating layer 130, a crystal layer, a second metal layer 160, and a protective layer 140. The base layer 190, the first metal layer 150, the insulating layer 130, the crystal layer, the second metal layer 160, and the protective layer 140 are stacked sequentially. In this arrangement, the crystal layer is disposed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the crystal layer. The display area 200 in the TFT substrate includes a base layer 190, a third metal layer 220, an insulating layer 130, a first amorphous layer 210, a fourth metal layer 230, and a protective layer 140. The base layer 190, the third metal layer 220, the insulating layer 130, the first amorphous layer 210, the fourth metal layer 230, and the protective layer 140 are stacked sequentially. In this arrangement, the first amorphous layer 210 is disposed between the insulating layer 130 and the protective layer 140, and the protective layer 140 can protect the first amorphous layer 210.

[0086] Examples such as Figure 7 As shown, step S03 in the above-mentioned TFT substrate fabrication method specifically includes the following steps:

[0087] S031. A photoresist layer 170 is formed on the first amorphous layer 210 and the insulating layer 130, wherein the photoresist layer 170 does not cover the third amorphous layer 111.

[0088] S032, A seed layer 112 is formed on the third amorphous layer 111;

[0089] S033. The third amorphous layer 111 is heated or irradiated with a laser to form a crystalline layer.

[0090] In step S032, a seed layer 112 is formed on the third amorphous layer 111. During the heating or laser irradiation of the third amorphous layer, the seed layer 112 can control the grain size and crystallization rate. After the crystalline layer is formed, due to its excellent etching resistance, it can prevent channel damage during the subsequent formation of the second metal layer 160.

[0091] Examples such as Figure 7As shown, the following steps are included after step S04 in the above-described method for preparing a TFT substrate:

[0092] S05. An organic film layer 180 is formed on the protective layer 140.

[0093] The present invention also provides a display panel, which includes the TFT substrate provided in the above embodiments. It should be noted that the display panel provided in the embodiments of the present invention may also include other circuits and devices for supporting the normal operation of the display panel, such as backlight components, polarizers, etc.

[0094] The present invention also provides a display device, which includes the display panel provided in the above embodiments. It should be noted that the display device provided in the embodiments of the present invention may also include other circuits and devices for supporting the normal operation of the display device. The above-mentioned display device can be one of a mobile phone, tablet computer, electronic paper, or electronic photo frame.

[0095] In summary, this application provides a TFT substrate and its fabrication method, a display panel, and a display device. The TFT substrate includes a display area 200 and a driving area 100, and the device mobility of the driving area 100 is higher than that of the display area 200. Increasing the device mobility of the driving area 100 improves device stability, reduces the possibility of threshold voltage shift in the driving circuit due to external environmental influences, and enhances the driving capability of the driving circuit, thereby improving the display stability of the display panel. Furthermore, this application also places a crystalline layer between an insulating layer 130 and a protective layer 140, with the protective layer 140 protecting the crystalline layer; and places a first amorphous layer 210 between the insulating layer 130 and the protective layer 140, with the protective layer 140 also protecting the crystalline layer. In addition, this application also provides a second amorphous layer 120 stacked with a crystalline layer; such a configuration forms a structure in which the second amorphous layer 120 and the crystalline layer are stacked. On the one hand, the second amorphous layer 120 can improve the film uniformity, and on the other hand, the crystalline layer can improve the device mobility.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A TFT substrate, characterized in that, The TFT substrate includes: Display area; and A driving area is used to drive the display area to perform display. The device mobility of the driving area is higher than that of the display area; The display area includes a first amorphous layer, and the driving area includes a crystalline layer and a second amorphous layer. The second amorphous layer is stacked with the crystalline layer, and the crystalline layer covers the second amorphous layer. The device mobility of the crystalline layer is higher than that of the first amorphous layer.

2. The TFT substrate according to claim 1, characterized in that, The first amorphous layer and the second amorphous layer are amorphous oxide semiconductor layers, and the crystalline layer is a crystalline oxide semiconductor layer.

3. The TFT substrate according to claim 1 or 2, characterized in that, The driving region further includes an insulating layer and a protective layer, with the crystalline layer disposed between the insulating layer and the protective layer.

4. The TFT substrate according to claim 3, characterized in that, The first amorphous layer is disposed between the insulating layer and the protective layer.

5. A method for preparing a TFT substrate, characterized in that, The TFT substrate is the TFT substrate according to any one of claims 1 to 4, and the preparation method includes the following steps: An insulating layer is formed on the substrate; A first amorphous layer and a second amorphous layer are formed on the insulating layer; A third amorphous layer is formed on the second amorphous layer; The third amorphous layer is heated or irradiated with a laser to form a crystalline layer; A protective layer is formed on the crystalline layer and the first amorphous layer.

6. A method for preparing a TFT substrate, characterized in that, The TFT substrate is the TFT substrate according to any one of claims 1 to 4, and the preparation method includes the following steps: An insulating layer is formed on the substrate; A first amorphous layer and a third amorphous layer are formed on the insulating layer; The third amorphous layer is heated or irradiated with a laser to form a crystalline layer; A protective layer is formed on the crystalline layer and the first amorphous layer.

7. A display panel, characterized in that, Includes the TFT substrate as described in any one of claims 1 to 4.

8. A display device, characterized in that, Includes the display panel as described in claim 7.

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