Display substrate, manufacturing method thereof and display device

Abstract

The application provides a display substrate, a manufacturing method thereof and a display device, and belongs to the technical field of display. The display substrate comprises a pixel circuit on a substrate, the pixel circuit comprising a driving thin film transistor, a switching thin film transistor and a gate drive circuit thin film transistor, the active layer of the driving thin film transistor and the active layer of the switching thin film transistor being located on different layers; and / or, the active layer of the driving thin film transistor and the active layer of the gate drive circuit thin film transistor being located on different layers. The technical scheme of the application can improve the display effect of the display device.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a display substrate, its manufacturing method, and a display device. Background Technology

[0002] In the field of flat panel display technology, thin film transistor displays (TFT-LCDs) have advantages such as small size, low power consumption, and relatively low manufacturing cost, and have gradually taken a dominant position in today's flat panel display market.

[0003] Organic light-emitting diodes (OLEDs), also known as organic electroluminescent displays or organic light-emitting semiconductors, use a different light-emitting principle than liquid crystal displays (LCDs). OLED display technology boasts advantages such as self-illumination, wide viewing angles, near-infinite contrast ratios, low power consumption, and extremely fast response times, and is considered the next-generation display technology, potentially replacing LCDs in the near future.

[0004] Transparent metal oxide thin film transistors (Oxide TFTs) have advantages such as high mobility, good uniformity at large generation lines, low manufacturing cost, and compatibility with a-Si production lines. In addition, Oxide TFTs have good hysteresis characteristics, which helps to improve the hysteresis problem of OLED products, and are increasingly favored by OLED products. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a display substrate and its manufacturing method, as well as a display device, which can improve the display effect of the display device.

[0006] To address the aforementioned technical problems, embodiments of the present invention provide the following technical solutions:

[0007] On one hand, a display substrate is provided, the display substrate including a pixel circuit located on a substrate, the pixel circuit including a driving thin-film transistor, a switching thin-film transistor, and a gate driving circuit thin-film transistor.

[0008] The active layer of the driving thin-film transistor and the active layer of the switching thin-film transistor are located on different layers; and / or

[0009] The active layer of the driving thin-film transistor and the active layer of the gate driving circuit thin-film transistor are located on different layers.

[0010] In some embodiments, the active layer of the switching thin-film transistor and the active layer of the gate driving circuit thin-film transistor are disposed on the same layer and made of the same material.

[0011] In some embodiments, the gate insulating layer of the driving thin film transistor has a thickness greater than that of the gate insulating layer of the switching thin film transistor; and / or

[0012] The gate insulating layer of the driving thin film transistor has a thickness greater than that of the gate insulating layer of the gate driving circuit thin film transistor.

[0013] In some embodiments, the active layer of the driving thin film transistor has an on-resistance greater than that of the active layer of the switching thin film transistor; and / or

[0014] The active layer of the driving thin film transistor has an on-resistance greater than that of the active layer of the gate driving circuit thin film transistor.

[0015] In some embodiments, the display substrate comprises an interlayer insulating layer on the side of the active layer of the driving thin film transistor away from the substrate, the interlayer insulating layer comprises a first sub-interlayer insulating layer and a second sub-interlayer insulating layer, the first sub-interlayer insulating layer is made of silicon oxide, the second sub-interlayer insulating layer is made of silicon nitride, and the second sub-interlayer insulating layer is on the side of the first sub-interlayer insulating layer away from the substrate.

[0016] In some embodiments, the active layer of the driving thin film transistor is treated by an annealing process.

[0017] In some embodiments, the active layer of the driving thin film transistor has a mobility less than that of the active layer of the switching thin film transistor; and / or

[0018] The active layer of the driving thin film transistor has a mobility less than that of the active layer of the gate driving circuit thin film transistor.

[0019] In some embodiments, the gate insulating layer of the driving thin film transistor has an area greater than that of the gate insulating layer of the switching thin film transistor; and / or

[0020] The gate insulating layer of the driving thin film transistor has an area greater than that of the gate insulating layer of the gate driving circuit thin film transistor.

[0021] In some embodiments, the storage capacitor of the pixel circuit comprises two plates arranged oppositely, and the plates are made of the gate of a thin film transistor or the conductive active layer.

[0022] Embodiments of the present application also provide a display device comprising the display substrate as described above.

[0023] The embodiment of the present application also provides a manufacturing method of a display substrate, the display substrate comprising a pixel circuit on a substrate, the pixel circuit comprising a driving thin film transistor, a switching thin film transistor and a gate drive circuit thin film transistor, the manufacturing method comprising:

[0024] The active layer of the driving thin film transistor and the active layer of the switching thin film transistor are manufactured by different patterning processes; and / or

[0025] The active layer of the driving thin film transistor and the active layer of the gate drive circuit thin film transistor are manufactured by different patterning processes.

[0026] In some embodiments, the manufacturing method further comprises:

[0027] The active layer of the switching thin film transistor and the active layer of the gate drive circuit thin film transistor are formed by one patterning process.

[0028] The embodiment of the present application has the following beneficial effects:

[0029] In the above scheme, the active layers of the driving thin film transistor, the switching thin film transistor and / or the gate drive circuit thin film transistor are formed by different patterning processes, and the driving thin film transistor, the switching thin film transistor and / or the gate drive circuit thin film transistor are formed separately and independently, so that the characteristics of the driving thin film transistor are not disturbed by the process and characteristics of the switching thin film transistor and the gate drive circuit thin film transistor, and the display effect of the high mobility Oxide OLED product can be improved by reducing the I on on of the driving thin film transistor and increasing the SS of the driving thin film transistor without affecting the driving capability of the switching thin film transistor and the gate drive circuit thin film transistor. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A schematic diagram of a pixel circuit of a display substrate is shown;

[0031] Figure 2 A schematic diagram of a structure of a related art display substrate is shown;

[0032] Figures 3-10 A schematic diagram of a structure of a display substrate according to an embodiment of the present application is shown.

[0033] REFERENCE NUMERALS

[0034] 01 substrate

[0035] 02 first flexible substrate

[0036] 03 first barrier layer

[0037] 04 second flexible substrate

[0038] 05 Second Barrier Layer

[0039] 06 First Buffer Layer

[0040] 07 First gate insulation layer

[0041] 08 Second gate insulation layer

[0042] 09 Interlayer insulation layer

[0043] 10 Source / Drain Metal Layers

[0044] 11. Active Layer

[0045] 12 First gate metal layer

[0046] 13 Second gate metal layer

[0047] 14 Second Buffer Layer

[0048] 15 Third gate insulation layer

[0049] 16 Third gate metal layer

[0050] 111 Active layer driving thin-film transistors

[0051] 17 First Sublayer Interlayer Insulation Layer

[0052] 18 Second Sublayer Interlayer Insulation Layer

[0053] 19 Vias Detailed Implementation

[0054] To make the technical problems, technical solutions and advantages of the embodiments of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0055] The pixel circuitry of existing OLED display products typically includes driving thin-film transistors (DTFTs), switching thin-film transistors (STFTs), storage capacitors (Cst), and light-emitting diodes (LEDs), such as... Figure 1 As shown.

[0056] Currently, OLED pixel circuits generally use low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) because their mobility can reach 50–100 cm⁻¹. 2 / (vs), LTPS TFTs have fast switching speeds when used as STFTs and can achieve narrow bezel and low power consumption displays when used as GOA (gate drive circuit) TFTs. However, when LTPS TFTs are used as DTFTs, due to their high mobility, the It of the TFT is limited.on Too large, since OLED is a current-driven device, I on Too large, which is not conducive to the expansion of different gray scale of OLED display, prone to low gray Mura problem, seriously affect the display effect of OLED products, in order to reduce the LTPS DTFT I on , on the one hand, the TFT L (channel length) is made larger (such as 20 um or more), on the other hand, through high temperature Anneal process, the subthreshold swing (SS) of LTPS DTFT is made larger, to reduce the LTPS DTFT I on , improve the display effect of OLED products.

[0057] Transparent metal oxide thin film transistor (Oxide TFT) due to its high mobility, good generation line uniformity, low manufacturing cost and can be compatible with a-Si production line and other advantages, and Oxide TFT hysteresis characteristics are good, conducive to improve the hysteresis problem of OLED products, more and more favored by the OLED products. However, the existing conventional oxide material such as IGZO mobility is 10 cm 2 / (v.s), such as using it to do STFT, the switching speed is not fast enough, especially such as using it to do DTFT, the frame can not be made smaller, which limits the application of Oxide TFT in OLED display products.

[0058] With the development of Oxide TFT technology, the mobility of oxide material above 20 cm 2 / (v.s), especially the mobility of oxide material above 30 cm 2 / (v.s) (such as ITZO, IGTO, IGZTO, etc.) or even the mobility of oxide material of 50 cm 2 / (v.s) gradually get the application. High mobility Oxide material such as applied to OLED display products, can improve the switching speed of STFT, reduce the frame of the product and reduce power consumption. However, when the high mobility Oxide material does Oxide DTFT, the same problem as LTPS DTFT will be encountered, that is, the I on of high mobility Oxide DTFT is large, which is not conducive to the expansion of different gray scale of OLED display, prone to low gray Mura problem, seriously affect the display effect of OLED products.

[0059] In order to improve the display effect of Oxide OLED display products, it is necessary to reduce the I on of high mobility Oxide DTFT. The existing polycrystalline LTPS DTFT usually increases the L of TFT (such as 20 um or more) to reduce I onHowever, for amorphous high-mobility Oxide TFTs, the difference in Vth between TFTs with small L (e.g., L is approximately 4 μm) and TFTs with large L (e.g., L is approximately 10 μm) is significant. That is, when the L of Oxide DTFTs and Oxide STFTs are different, different processes are needed to control Vth; another aspect of polycrystalline LTPS DTFTs is reducing I... on The method involves using a high-temperature Anneal process to cause hydrogen (H) to escape from the LTPS DTFT, increasing the defects in the DTFT and thus increasing its SS (superconductivity, spectral density), thereby reducing the I (intensity, spectral density) of the DTFT. on However, for amorphous high-mobility Oxide TFTs, generally, the higher the mobility, the worse the TFT stability. Therefore, high-mobility Oxide materials are generally selected with a mobility of 30 cm⁻¹. 2 The material with a mobility of / (vs) under these mobility conditions has a lower mobility than the LTPS TFT. If the I of the DTFT is reduced by increasing SS... on The I of STFT and GOA TFT on It will also inevitably be affected, STFT I on Reducing the speed will affect the switching speed of the STFT, GOA TFT I on When the size is reduced, the W (channel width) dimension of the GOA TFT needs to be increased to enhance the driving capability, which will increase the bezel of the OLED product.

[0060] When using high-mobility oxides to make OLED display products, DTFT I on An excessively large DTFT I and an excessively small SS (Spectrum Surface Area) are detrimental to the unfolding of different gray levels in OLED displays, easily leading to low-gray-level mura defects and severely impacting the display performance of OLED products. However, by reducing the DTFT I... on Increasing the DTFT SS to improve display performance will affect the I of the STFT and GOA TFT. on This, in turn, affects the driving capability of STFT and GOA TFT, as well as the display effect and bezel of the product.

[0061] This invention provides a display substrate, such as... Figure 3 As shown, the display substrate includes a pixel circuit located on the substrate, and the pixel circuit includes a driving thin-film transistor B, a switching thin-film transistor C, and a gate driving circuit thin-film transistor A.

[0062] The active layer of the driving thin-film transistor B and the active layer of the switching thin-film transistor C are located on different layers; and / or

[0063] The active layer of the driving thin-film transistor B is located on a different layer from the active layer of the gate driving circuit thin-film transistor A.

[0064] As Figure 2 shown in the related art, the display substrate sequentially comprises a first flexible substrate 02, a first barrier layer 03, a second flexible substrate 04, a second barrier layer 05, a first buffer layer 06, a first gate insulating layer 07, a second gate insulating layer 08, an interlayer insulating layer 09, a first gate metal layer 12, a second gate metal layer 13, an active layer 11 and a source-drain metal layer 10 on the substrate 01. The active layer 11 of the driving thin film transistor B, the switching thin film transistor C and the gate drive circuit thin film transistor A are arranged in the same layer and are made of the same material, so it is difficult to meet the characteristic requirements of the driving thin film transistor B, the switching thin film transistor C and the gate drive circuit thin film transistor A.

[0065] In the embodiment of the present application, the active layer of the driving thin film transistor B is located in a different layer from the active layer of the switching thin film transistor C and / or the gate drive circuit thin film transistor A, so that the active layer of the driving thin film transistor and the active layer of the switching thin film transistor and / or the gate drive circuit thin film transistor can be formed by different patterning processes. The driving thin film transistor and the switching thin film transistor and / or the gate drive circuit thin film transistor are formed separately and independently, so that the characteristics of the driving thin film transistor are not disturbed by the process and characteristics of the switching thin film transistor and the gate drive circuit thin film transistor. Furthermore, the display effect of the high mobility Oxide OLED product can be improved by reducing the I on and increasing the SS of the driving thin film transistor without affecting the driving capability of the switching thin film transistor and the gate drive circuit thin film transistor.

[0066] In the embodiment, only the active layer of the driving thin film transistor B and the active layer of the switching thin film transistor C are located in different layers, so that the active layer of the driving thin film transistor B and the active layer of the switching thin film transistor C can be formed by different patterning processes. Alternatively, only the active layer of the driving thin film transistor B and the active layer of the gate drive circuit thin film transistor A are located in different layers, so that the active layer of the driving thin film transistor B and the active layer of the gate drive circuit thin film transistor A can be formed by different patterning processes. Alternatively, the active layer of the driving thin film transistor B and the active layer of the switching thin film transistor C are located in different layers, and the active layer of the driving thin film transistor B and the active layer of the gate drive circuit thin film transistor A are located in different layers, so that the active layer of the driving thin film transistor B and the active layer of the switching thin film transistor C can be formed by different patterning processes, and the active layer of the driving thin film transistor B and the active layer of the gate drive circuit thin film transistor A can be formed by different patterning processes.

[0067] In some embodiments, the active layer of the switch thin film transistor and the active layer of the gate drive circuit thin film transistor are formed by the same patterning process.

[0068] In the embodiment, the active layers of the drive thin film transistor B, the switch thin film transistor C and the gate drive circuit thin film transistor A can be transparent metal oxide semiconductor.

[0069] In some embodiments, the gate insulating layer of the drive thin film transistor has a thickness greater than that of the gate insulating layer of the switch thin film transistor; and / or

[0070] The gate insulating layer of the drive thin film transistor has a thickness greater than that of the gate insulating layer of the gate drive circuit thin film transistor.

[0071] By increasing the thickness of the gate insulating layer of the drive thin film transistor, the I on of the drive thin film transistor can be reduced without affecting the driving capability of the switch thin film transistor and the gate drive circuit thin film transistor, and the SS of the drive thin film transistor is increased, thereby improving the display effect of the high mobility Oxide OLED product.

[0072] In some embodiments, the active layer of the drive thin film transistor has a turn-on resistance greater than that of the active layer of the switch thin film transistor; and / or

[0073] The active layer of the drive thin film transistor has a turn-on resistance greater than that of the active layer of the gate drive circuit thin film transistor.

[0074] By increasing the turn-on resistance of the active layer of the drive thin film transistor, the I on of the drive thin film transistor can be reduced without affecting the driving capability of the switch thin film transistor and the gate drive circuit thin film transistor, and the SS of the drive thin film transistor is increased, thereby improving the display effect of the high mobility Oxide OLED product.

[0075] In some embodiments, the display substrate comprises an interlayer insulating layer on the side of the active layer of the drive thin film transistor away from the substrate, the interlayer insulating layer comprises a first sub-interlayer insulating layer and a second sub-interlayer insulating layer, the first sub-interlayer insulating layer is silicon oxide, the second sub-interlayer insulating layer is silicon nitride, and the second sub-interlayer insulating layer is on the side of the first sub-interlayer insulating layer away from the substrate.

[0076] In this embodiment, the second sub-layer interlayer insulating layer is made of silicon nitride, which contains hydrogen (H). The H in the second sub-layer interlayer insulating layer can diffuse to the active layer of the driving thin-film transistor. The more H in the second sub-layer interlayer insulating layer, the more H diffuses to the active layer of the driving thin-film transistor, and the greater the I / O of the driving thin-film transistor. on The larger the value, the less H is in the insulating layer between the second sublayers, the less H diffuses into the active layer driving the thin-film transistor, and the greater the I of the driving thin-film transistor. on The smaller the value, the better. Therefore, the Ik of the driving thin-film transistor can be adjusted by controlling the hydrogen content of the second sublayer insulating layer. on The size can be adjusted to reduce the IG of the driving thin-film transistor without affecting the driving capability of the switching thin-film transistor and the gate driving circuit. on This improves the display performance of high-mobility OxideOLED products.

[0077] In some embodiments, the active layer of the driving thin-film transistor is subjected to an annealing process. The annealing process can increase the SS of the driving thin-film transistor. This can increase the SS of the driving thin-film transistor without affecting the driving capability of the switching thin-film transistor and the gate driving circuit thin-film transistor, thereby improving the display effect of high mobility Oxide OLED products.

[0078] In some embodiments, in order to reduce the IT of the driving thin-film transistor on The mobility of the active layer of the driving thin-film transistor is less than the mobility of the active layer of the switching thin-film transistor; and / or

[0079] The mobility of the active layer of the driving thin-film transistor is less than that of the active layer of the gate driving circuit thin-film transistor.

[0080] The active layer of the driving thin-film transistor can use an Oxide material with low mobility, such as IGZO, while the active layers of the gate driving circuit thin-film transistor and the off-film transistor can use an Oxide material with high mobility, such as ITZO, IGTO, and IGZTO.

[0081] In some embodiments, in order to reduce the IT of the driving thin-film transistor on Increase the I of the switching thin-film transistor on The area of ​​the gate insulating layer of the driving thin-film transistor is larger than the area of ​​the gate insulating layer of the switching thin-film transistor; and / or

[0082] To reduce the Ii of the driving thin-film transistor on Increase the I of the thin-film transistor in the gate drive circuit on The area of ​​the gate insulating layer of the driving thin film transistor is larger than the area of ​​the gate insulating layer of the thin film transistor of the gate driving circuit.

[0083] In one specific embodiment, such as Figure 3 As shown, the display substrate sequentially includes a first flexible substrate 02, a first barrier layer 03, a second flexible substrate 04, a second barrier layer 05, a first buffer layer 06, a first gate insulating layer 07, a second gate insulating layer 08, a second buffer layer 14, a third gate insulating layer 15, a first gate metal layer 12, and a second gate metal layer 13, all located on a substrate 01. The active layers 11 of the gate driving circuit thin-film transistor A and the switching thin-film transistor C are disposed on the same layer and made of the same material, while the active layer 111 of the driving thin-film transistor B is located on a different layer from the active layers 11 of the gate driving circuit thin-film transistor A and the switching thin-film transistor C. The gate driving circuit of thin-film transistor A uses a first gate metal layer 12 for the gate and a first gate insulating layer 07 for the gate insulating layer; the switching thin-film transistor C adopts a dual-gate structure, with a first gate metal layer 12 and a second gate metal layer 13 for the gate, and a first gate insulating layer 07 and a second gate insulating layer 08 for the gate insulating layer; the driving thin-film transistor B uses a second gate metal layer 13 for the gate and a third gate insulating layer 15 for the gate insulating layer. This is to reduce the Ig of the driving thin-film transistor B. on The SS of the driving thin-film transistor B is increased, and the third gate insulating layer 03 is thickened. The thickness of the first gate insulating layer 07 and the second gate insulating layer 08 are both... The thickness of the third gate insulating layer 03 is increased to By fabricating the driving thin-film transistor B separately from the gate driving circuit thin-film transistor A and the switching thin-film transistor C, the driving capability of the Oxide STFT (i.e., the switching thin-film transistor) and GOA TFT (i.e., the gate driving circuit thin-film transistor) is reduced without affecting the driving capability of the DTFT (i.e., the driving thin-film transistor). on And increase the DTFT SS to improve the display performance of high mobility Oxide OLED products.

[0084] like Figure 4 As shown, the driving thin-film transistor B can adopt a dual-gate structure. The gate of the driving thin-film transistor B can adopt a second gate metal layer 13 and a third gate metal layer 16. Using the third gate metal layer 16 as a mask, the active layer 111 of the driving thin-film transistor B can be doped to make the active layer 111 conductive. In order to reduce the I of the Oxide DTFT... on It is not necessary to fully conductor the active layer 111 of the DTFT; that is, a process method with relatively low doping energy and dosage can be used to reduce the I of the DTFT by increasing the on-resistance of the active layer 111. on For Oxide STFTs and GOA TFTs, relatively high-energy and high-dosage processing methods are required to fully conductor the active layer 11, thereby increasing the IT of the STFT and GOA TFT. on, enhance the driving ability. By the method of forming the Oxide DTFT separately from the Oxide STFT and the GOA TFT, the display effect of the high mobility Oxide OLED product is improved by reducing the DTFT I on and increasing the DTFT SS without affecting the driving ability of the Oxide STFT and the GOA TFT.

[0085] As shown in Figure 5 , the first interlayer insulating layer 17 and the second interlayer insulating layer 18 are arranged on the side of the active layer 111 away from the substrate. The first interlayer insulating layer 17 is made of SiO, and the second interlayer insulating layer 18 is made of SiN. By adjusting the H content in SiN, the I on of the Oxide DTFT can be adjusted. The greater the thickness of the second interlayer insulating layer 18, the higher the H content, and the H released from the second interlayer insulating layer 18 combines with the oxygen in the active layer 111, reducing the on-resistance of the active layer 111, so that the I on of the Oxide DTFT is greater; the smaller the thickness of the second interlayer insulating layer 18, the lower the H content, increasing the on-resistance of the active layer 111, so that the I on of the Oxide DTFT is smaller. By the method of forming the Oxide DTFT separately from the Oxide STFT and the GOA TFT, the display effect of the high mobility Oxide OLED product is improved by reducing the DTFT I on without affecting the driving ability of the Oxide STFT and the GOA TFT.

[0086] As shown in Figure 6 , after the interlayer insulating layer is formed, a via hole 19 exposing the active layer 111 can be formed, and the active layer 111 is annealed through the via hole 19 at a temperature of 300-400℃. Then, as shown in Figure 7 , a via hole exposing the active layer 11 is formed without annealing. In this way, the SS of the Oxide DTFT can be increased by the annealing process. During the annealing process, the via holes of the Oxide STFT and the Oxide GOA TFT are not opened, so the SS of the Oxide STFT and the Oxide GOA TFT is not affected. By the method of forming the Oxide DTFT separately from the Oxide STFT and the GOA TFT, the display effect of the high mobility Oxide OLED product is improved by increasing the DTFT SS without affecting the driving ability of the Oxide STFT and the GOA TFT.

[0087] As shown in Figure 8As shown, the source and drain of the driving thin-film transistor B, the gate driving circuit thin-film transistor A, and the switching thin-film transistor C can be fabricated using the source and drain metal layer 10.

[0088] like Figure 9 As shown, since the Oxide DTFT is formed separately from the Oxide STFT and GOA TFT, in order to increase the Ig of the Oxide STFT and Oxide GOA TFT... on When etching the first gate metal layer 12, the first gate insulating layer 07 can be etched simultaneously, leaving only the first gate insulating layer 07 directly below the first gate metal layer 12 as the gate insulating layer for the Oxide STFT and Oxide GOA TFT, while the third gate insulating layer 15 of the Oxide DTFT is completely retained. This can reduce the Ig of the Oxide DTFT. on .

[0089] In the above embodiments, the active layer 111 of the Oxide DTFT is located on the side of the active layer 11 of the Oxide STFT and Oxide GOA TFT that is away from the substrate. For example... Figure 10 As shown, the active layer 111 of the Oxide DTFT can also be located on the side of the active layer 11 of the Oxide STFT and Oxide GOA TFT close to the substrate. The gate insulating layer of the Oxide DTFT includes a first gate insulating layer 07 and a second gate insulating layer 08, and the gate uses a first gate metal layer 12 and a second gate metal layer 13; the gate insulating layer of the Oxide STFT and Oxide GOA TFT includes a third gate insulating layer 15, and the gate uses a third gate metal layer 16 and a second gate metal layer 13. To reduce the Ig of the Oxide DTFT... on To increase the SS of the Oxide DTFT, the first gate insulating layer 07 needs to be thickened so that the thickness of the first gate insulating layer 07 is greater than the thickness of the third gate insulating layer 15.

[0090] In this embodiment, to adjust the size of the storage capacitor in the pixel circuit to meet design requirements, the two oppositely positioned plates of the storage capacitor can be selected from two of the following: a first gate metal layer 12, a second gate metal layer 13, a third gate metal layer 16, a conductive active layer 11, and a conductive active layer 111. The storage capacitor can be located on the side of the Oxide DTFT closer to the substrate or on the side of the Oxide DTFT farther from the substrate.

[0091] Embodiments of the present invention also provide a display device, including a display substrate as described above.

[0092] The display device includes, but is not limited to, a radio frequency unit, a network module, an audio output unit, an input unit, a sensor, a display unit, a user input unit, an interface unit, a memory, a processor, and a power supply, and the like. Those skilled in the art can understand that the structure of the display device does not constitute a limitation on the display device, and the display device can include more or less components, or combine certain components, or different component arrangements. In the embodiments of the present application, the display device includes, but is not limited to, a display, a mobile phone, a tablet computer, a television, a wearable electronic device, a navigation display device, and the like.

[0093] The display device can be a television, a display, a digital photo frame, a mobile phone, a tablet computer, or any product or component with display function, wherein the display device further includes a flexible circuit board, a printed circuit board, and a back plate.

[0094] Embodiments of the present application also provide a manufacturing method of a display substrate, the display substrate including a pixel circuit on a substrate, the pixel circuit including a driving thin film transistor, a switching thin film transistor, and a gate drive circuit thin film transistor, the manufacturing method including:

[0095] manufacturing the active layer of the driving thin film transistor and the active layer of the switching thin film transistor through different patterning processes; and / or

[0096] manufacturing the active layer of the driving thin film transistor and the active layer of the gate drive circuit thin film transistor through different patterning processes.

[0097] In the embodiments of the present application, different patterning processes can be used to form the active layers of the driving thin film transistor, the switching thin film transistor, and / or the gate drive circuit thin film transistor. The driving thin film transistor, the switching thin film transistor, and / or the gate drive circuit thin film transistor are formed separately, which can make the characteristics of the driving thin film transistor not be disturbed by the process and characteristics of the switching thin film transistor and the gate drive circuit thin film transistor, and thus the I on and the SS of the driving thin film transistor can be increased to improve the display effect of the high-mobility Oxide OLED product.

[0098] In this embodiment, the active layer of the driving thin-film transistor B and the active layer of the switching thin-film transistor C can be formed using only different patterning processes; or, the active layer of the driving thin-film transistor B and the active layer of the gate driving circuit thin-film transistor A can be formed using only different patterning processes; or, the active layer of the driving thin-film transistor B and the active layer of the switching thin-film transistor C can be formed using different patterning processes; and, the active layer of the driving thin-film transistor B and the active layer of the gate driving circuit thin-film transistor A can be formed using different patterning processes.

[0099] In some embodiments, the manufacturing method further includes:

[0100] The active layers of the switching thin-film transistor and the gate driving circuit thin-film transistor are formed in a single patterning process. This simplifies the fabrication process of the display substrate.

[0101] In this embodiment, the active layer of the driving thin-film transistor B, the switching thin-film transistor C, and the gate driving circuit thin-film transistor A can be made of transparent metal oxide semiconductor.

[0102] In one specific embodiment, such as Figure 3 As shown, during the fabrication of the display substrate, a first flexible substrate 02, a first barrier layer 03, a second flexible substrate 04, a second barrier layer 05, a first buffer layer 06, an active layer 11, a first gate insulating layer 07, a first gate metal layer 12, a second gate insulating layer 08, a second gate metal layer 13, a second buffer layer 14, and a third gate insulating layer 15 are sequentially formed on the substrate 01. The active layers 11 of the gate driving circuit thin-film transistor A and the switching thin-film transistor C are disposed on the same layer and made of the same material, and are formed through a single patterning process. The active layer 111 of the driving thin-film transistor B is located on a different layer from the active layers 11 of the gate driving circuit thin-film transistor A and the switching thin-film transistor C, and is formed through a different patterning process. The gate driving circuit of thin-film transistor A uses a first gate metal layer 12 for the gate and a first gate insulating layer 07 for the gate insulating layer; the switching thin-film transistor C adopts a dual-gate structure, with a first gate metal layer 12 and a second gate metal layer 13 for the gate, and a first gate insulating layer 07 and a second gate insulating layer 08 for the gate insulating layer; the driving thin-film transistor B uses a second gate metal layer 13 for the gate and a third gate insulating layer 15 for the gate insulating layer. This is to reduce the Ig of the driving thin-film transistor B. on The SS of the driving thin-film transistor B is increased, and the third gate insulating layer 03 is thickened. The thickness of the first gate insulating layer 07 and the second gate insulating layer 08 are both... The thickness of the third gate insulating layer 03 is increased to By separately manufacturing the driving thin film transistor B and the gate driving circuit thin film transistor A and the switching thin film transistor C, the display effect of the high mobility Oxide OLED product is improved by reducing the DTFT (i.e. the driving thin film transistor) I on and increasing the DTFT SS without affecting the driving capability of the Oxide STFT (i.e. the switching thin film transistor) and the GOA TFT (i.e. the gate driving circuit thin film transistor).

[0103] As shown in Figure 4 , the driving thin film transistor B can adopt a double-gate structure, and the gate of the driving thin film transistor B can adopt the second gate metal layer 13 and the third gate metal layer 16. The third gate metal layer 16 is used as a mask to dope the active layer 111 of the driving thin film transistor B to make the active layer 111 conductive. In order to reduce the I on of the Oxide DTFT, the active layer 111 of the DTFT does not need to be completely conductive, i.e. a process method with relatively small energy and dosage can be used to reduce the I on of the DTFT by increasing the on-resistance of the active layer 111. However, for the Oxide STFT and the GOA TFT, a process method with relatively large energy and dosage is needed to make the active layer 11 completely conductive to increase the I on of the STFT and the GOA TFT to enhance the driving capability. By the method of separately forming the Oxide DTFT from the Oxide STFT and the GOA TFT, the display effect of the high mobility Oxide OLED product is improved by reducing the DTFT I on and increasing the DTFT SS without affecting the driving capability of the Oxide STFT and the GOA TFT.

[0104] As shown in Figure 5 , the first interlayer insulating layer 17 and the second interlayer insulating layer 18 are formed on the side of the active layer 111 away from the substrate. The first interlayer insulating layer 17 adopts SiO, and the second interlayer insulating layer 18 adopts SiN. By adjusting the H content in the SiN, the I on of the Oxide DTFT can be adjusted. The greater the thickness of the second interlayer insulating layer 18, the higher the H content. The H escaped from the second interlayer insulating layer 18 combines with the oxygen in the active layer 111 to reduce the on-resistance of the active layer 111, so that the I on of the Oxide DTFT is greater; the smaller the thickness of the second interlayer insulating layer 18, the lower the H content, which increases the on-resistance of the active layer 111, so that the I onThe smaller the value, the better. By forming the Oxide DTFT, Oxide STFT, and GOA TFT independently, the driving capability of the Oxide STFT and GOA TFT can be reduced without affecting their performance. on To improve the display performance of high-mobility Oxide OLED products.

[0105] like Figure 6 As shown, after forming the interlayer insulating layer, vias 19 can be formed to expose the active layer 111. The active layer 111 is then annealed through the vias 19 at a temperature of 300°C to 400°C. Afterwards, as... Figure 7 As shown, vias are formed to expose the active layer 11 without annealing. This allows the SS (space spectral density) of the Oxide DTFT to be increased through annealing. During annealing, since the vias of the Oxide STFT and Oxide GOA TFT are not opened, the SS of the Oxide STFT and Oxide GOA TFT remains unaffected. By forming the Oxide DTFT separately from the Oxide STFT and GOA TFT, the display performance of high-mobility Oxide OLED products can be improved by increasing the DTFT SS without affecting the driving capability of the Oxide STFT and GOA TFT.

[0106] like Figure 8 As shown, the source and drain of the driving thin-film transistor B, the gate driving circuit thin-film transistor A, and the switching thin-film transistor C are formed using a source and drain metal layer 10.

[0107] like Figure 9 As shown, since the Oxide DTFT is formed separately from the Oxide STFT and GOA TFT, in order to increase the Ig of the Oxide STFT and Oxide GOA TFT... on When etching the first gate metal layer 12, the first gate insulating layer 07 can be etched simultaneously, leaving only the first gate insulating layer 07 directly below the first gate metal layer 12 as the gate insulating layer for the Oxide STFT and Oxide GOA TFT, while the third gate insulating layer 15 of the Oxide DTFT is completely retained. This can reduce the Ig of the Oxide DTFT. on .

[0108] In the above embodiments, the active layer 111 of the Oxide DTFT is located on the side of the active layer 11 of the Oxide STFT and Oxide GOA TFT that is away from the substrate. For example... Figure 10As shown, the active layer 111 of the Oxide DTFT can also be located on the side of the active layer 11 of the Oxide STFT and Oxide GOA TFT close to the substrate. The gate insulating layer of the Oxide DTFT includes a first gate insulating layer 07 and a second gate insulating layer 08, and the gate uses a first gate metal layer 12 and a second gate metal layer 13; the gate insulating layer of the Oxide STFT and Oxide GOA TFT includes a third gate insulating layer 15, and the gate uses a third gate metal layer 16 and a second gate metal layer 13. To reduce the Ig of the Oxide DTFT... on To increase the SS of the Oxide DTFT, the first gate insulating layer 07 needs to be thickened so that the thickness of the first gate insulating layer 07 is greater than the thickness of the third gate insulating layer 15.

[0109] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, since the embodiments are basically similar to the product embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the product embodiments.

[0110] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0111] It is understandable that when a component such as a layer, film, region, or substrate is referred to as being "above" or "below" another component, the component may be "directly" located "above" or "below" the other component, or there may be intermediate components present.

[0112] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0113] The above merely provides the specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A display substrate comprising a pixel circuit on a substrate, the pixel circuit comprising a driving thin film transistor, a switching thin film transistor and a gate drive circuit thin film transistor, characterized in that, the active layer of the driving thin film transistor is located in a different layer from the active layer of the switching thin film transistor; and / or the active layer of the driving thin film transistor is located in a different layer from the active layer of the gate drive circuit thin film transistor; the display substrate comprises an interlayer insulating layer on a side of the active layer of the driving thin film transistor away from the substrate, the interlayer insulating layer comprises a first sub-interlayer insulating layer and a second sub-interlayer insulating layer, the first sub-interlayer insulating layer is made of silicon oxide, the second sub-interlayer insulating layer is made of silicon nitride, and the second sub-interlayer insulating layer is located on a side of the first sub-interlayer insulating layer away from the substrate; the interlayer insulating layer comprises a via hole corresponding to the active layer of the driving thin film transistor, and the active layer of the driving thin film transistor is subjected to an annealing process through the via hole. The active layer of the switching thin film transistor and the active layer of the gate drive circuit thin film transistor are arranged in the same layer and made of the same material. 3.The display substrate according to claim 1, characterized in that, the thickness of the gate insulating layer of the driving thin film transistor is greater than the thickness of the gate insulating layer of the switching thin film transistor; and / or the thickness of the gate insulating layer of the driving thin film transistor is greater than the thickness of the gate insulating layer of the gate drive circuit thin film transistor. 4.The display substrate according to claim 1, characterized in that, the on-resistance of the active layer of the driving thin film transistor is greater than the on-resistance of the active layer of the switching thin film transistor; and / or the on-resistance of the active layer of the driving thin film transistor is greater than the on-resistance of the active layer of the gate drive circuit thin film transistor. The active layer of the driving thin film transistor is subjected to an annealing process.

2. The display substrate of claim 1, wherein, 6.The display substrate according to claim 1, characterized in that, the mobility of the active layer of the driving thin film transistor is less than the mobility of the active layer of the switching thin film transistor; and / or the mobility of the active layer of the driving thin film transistor is less than the mobility of the active layer of the gate drive circuit thin film transistor. 7.The display substrate according to claim 1, characterized in that, the area of the gate insulating layer of the driving thin film transistor is greater than the area of the gate insulating layer of the switching thin film transistor; and / or the area of the gate insulating layer of the driving thin film transistor is greater than the area of the gate insulating layer of the gate drive circuit thin film transistor. The storage capacitor of the pixel circuit comprises two plates arranged oppositely, and the plates are made of the gate of a thin film transistor or the conductive active layer. The display substrate according to any one of claims 1-8. The manufacturing method of the display substrate according to any one of claims 1-8, comprising: manufacturing the active layer of the driving thin film transistor and the active layer of the switching thin film transistor through different patterning processes; and / or manufacturing the active layer of the driving thin film transistor and the active layer of the gate drive circuit thin film transistor through different patterning processes. ​ ​ 5.The display substrate of claim 1, wherein, ​ ​ ​ ​ ​ ​ ​ 8.The display substrate of claim 1, wherein, ​ 9. A display device, characterized by comprising: ​ 10. A method for manufacturing a display substrate including a pixel circuit on a substrate, the pixel circuit including a drive thin film transistor, a switching thin film transistor, and a gate driver circuit thin film transistor, characterized by, ​ ​ The active layer of the driving thin film transistor and the active layer of the gate driving circuit thin film transistor are manufactured by different patterning processes; The interlayer insulating layer comprises a via hole corresponding to the active layer of the driving thin film transistor, and the method further comprises: The active layer of the driving thin film transistor is treated by an annealing process through the via hole.

11. The manufacturing method of the display substrate according to claim 10, characterized in that, The manufacturing method further comprises: The active layer of the switching thin film transistor and the active layer of the gate driving circuit thin film transistor are formed by one patterning process.

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