CN111864069A - Thin film transistor, preparation method thereof and display device - Google Patents

Thin film transistor, preparation method thereof and display device Download PDF

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Publication number
CN111864069A
CN111864069A CN201910346336.6A CN201910346336A CN111864069A CN 111864069 A CN111864069 A CN 111864069A CN 201910346336 A CN201910346336 A CN 201910346336A CN 111864069 A CN111864069 A CN 111864069A
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thin film
film transistor
substrate
insulating layer
pattern
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袁广才
郭康
董学
卢鑫泓
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BOE Technology Group Co Ltd
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BOE Technology Group Co Ltd
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Priority to CN201910346336.6A priority Critical patent/CN111864069A/en
Priority to PCT/CN2020/076258 priority patent/WO2020215875A1/en
Publication of CN111864069A publication Critical patent/CN111864069A/en
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having potential barriers
    • H10K10/40—Organic transistors
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K10/00—Organic devices specially adapted for rectifying, amplifying, oscillating or switching; Organic capacitors or resistors having potential barriers
    • H10K10/40—Organic transistors
    • H10K10/46—Field-effect transistors, e.g. organic thin-film transistors [OTFT]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
    • H01L27/12—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
    • H01L27/12—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body
    • H01L27/1214—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/191—Deposition of organic active material characterised by provisions for the orientation or alignment of the layer to be deposited
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/60—Forming conductive regions or layers, e.g. electrodes
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/20—Carbon compounds, e.g. carbon nanotubes or fullerenes
    • H10K85/221—Carbon nanotubes

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  • Condensed Matter Physics & Semiconductors (AREA)
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  • Thin Film Transistor (AREA)

Abstract

The embodiment of the invention provides a thin film transistor, a preparation method thereof and a display device, relates to the technical field of display, and can improve the mobility of the thin film transistor. The thin film transistor comprises an insulating layer arranged on a substrate, an active pattern comprising carbon nanotubes, a source electrode and a drain electrode; the active pattern comprises a plurality of strip-shaped sub-patterns which extend along a first direction and are arranged at intervals; along the first direction, one end of each strip-shaped sub-pattern in the active pattern is in contact with the source electrode, and the other end of each strip-shaped sub-pattern in the active pattern is in contact with the drain electrode; the insulating layer comprises a plurality of strip-shaped grooves, the grooves correspond to the strip-shaped sub-patterns one to one, and the orthographic projections of the grooves on the substrate are completely overlapped with the orthographic projections of the strip-shaped sub-patterns on the substrate.

Description

Thin film transistor, preparation method thereof and display device
Technical Field
The invention relates to the technical field of display, in particular to a thin film transistor, a preparation method thereof and a display device.
Background
In recent years, the demand of users for high-quality display panels has been increasing, and the demand for Thin-film transistors (TFTs) has also been increasing.
Currently, Low Temperature Polysilicon (LTPS) or oxide semiconductor is commonly used as the material of the active layer. However, the TFT using low-temperature polysilicon as the active layer material has a problem that uniformity is poor and it is difficult to realize a large-sized display panel. A TFT using an oxide semiconductor as a material of an active layer has a problem of low mobility.
Disclosure of Invention
Embodiments of the present invention provide a thin film transistor, a method for manufacturing the same, and a display device, which can improve mobility of the thin film transistor.
In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:
in a first aspect, a thin film transistor is provided, including an insulating layer disposed on a substrate, an active pattern including carbon nanotubes, a source electrode, and a drain electrode; the active pattern comprises a plurality of strip-shaped sub-patterns which extend along a first direction and are arranged at intervals; along the first direction, one end of each strip-shaped sub-pattern in the active pattern is in contact with the source electrode, and the other end of each strip-shaped sub-pattern in the active pattern is in contact with the drain electrode; the insulating layer comprises a plurality of strip-shaped grooves, the grooves correspond to the strip-shaped sub-patterns one to one, and the orthographic projections of the grooves on the substrate are completely overlapped with the orthographic projections of the strip-shaped sub-patterns on the substrate.
Optionally, the bar-shaped sub-patterns are filled in the grooves; the surface of one side, close to the substrate, of the strip-shaped sub-pattern is flush with the bottom surface of the groove corresponding to the strip-shaped sub-pattern.
Optionally, the groove penetrates through the insulating layer; each groove is filled with a decorative pattern; the active pattern is arranged on one side, away from the substrate, of the modification pattern; the modification patterns are in one-to-one correspondence with the strip-shaped sub-patterns and are in direct contact with the strip-shaped sub-patterns, and the orthographic projection of the modification patterns on the substrate and the orthographic projection of the corresponding strip-shaped sub-patterns on the substrate are completely overlapped; wherein the material of the modification pattern does not chemically react with the material of the insulating layer.
Optionally, the thin film transistor is a bottom gate thin film transistor; the insulating layer is arranged on one side, close to the substrate, of the active pattern; the groove does not penetrate through the insulating layer; or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor; the insulating layer is arranged on one side, close to the substrate, of the active pattern; the groove does not penetrate through the insulating layer.
Optionally, the thin film transistor is a bottom gate thin film transistor; the thin film transistor also comprises a gate insulating layer arranged on the substrate, and the gate insulating layer is arranged on one side, close to the substrate, of the insulating layer; or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor; the thin film transistor further comprises a buffer layer arranged on the substrate, and the buffer layer is arranged on one side, close to the substrate, of the insulating layer.
Optionally, the thin film transistor is a bottom gate thin film transistor; the thin film transistor also comprises a gate insulating layer arranged on the substrate, the gate insulating layer is arranged on one side, close to the substrate, of the insulating layer, and the modification pattern is in direct contact with the gate insulating layer; or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor; the thin film transistor further comprises a buffer layer arranged on the substrate, the buffer layer is arranged on one side, close to the substrate, of the insulating layer, and the decoration pattern is in direct contact with the buffer layer.
Optionally, the material of the modification pattern is an amphoteric coupling agent, the amphoteric coupling agent is a silane coupling agent, and the material of the insulating layer is a hydrophobic insulating material; the material of the gate insulating layer in the bottom gate type thin film transistor can chemically react with carboxyl; alternatively, the material of the buffer layer in the top gate thin film transistor or the double gate thin film transistor may chemically react with a carboxyl group.
Optionally, the width range of the cross section of the bar-shaped sub-pattern is greater than or equal to 500nm and less than 1000 nm; wherein the cross section is perpendicular to a thickness direction of the substrate, and a width of the cross section is perpendicular to the first direction.
In a second aspect, a display device is provided, including an array substrate including a pixel circuit including a driving transistor; the driving transistor is the thin film transistor of the first aspect.
In a third aspect, a method for manufacturing a thin film transistor is provided, including: forming an insulating film on a substrate, and forming a plurality of strip-shaped grooves which extend along a first direction and are arranged at intervals in the insulating film to obtain an insulating layer; forming an active pattern comprising carbon nanotubes on one side of the insulating layer, which is far away from the substrate; the active pattern comprises a plurality of strip-shaped sub-patterns arranged at intervals; the bar-shaped sub-patterns correspond to the grooves one by one, and the orthographic projections of the bar-shaped sub-patterns on the substrate are completely overlapped with the orthographic projections of the corresponding grooves on the substrate; and forming a source electrode and a drain electrode on one side of the active pattern, which is far away from the substrate, wherein one end of each strip-shaped sub-pattern in the active pattern is in contact with the source electrode, and the other end of each strip-shaped sub-pattern in the active pattern is in contact with the drain electrode along the first direction.
Optionally, the groove penetrates through the insulating layer; after the insulating layer is formed and before the active pattern is formed, the method for manufacturing a thin film transistor further includes: filling a decorative pattern into each groove; the modification patterns are arranged on one side, close to the substrate, of the active pattern, the modification patterns are in one-to-one correspondence with the strip-shaped sub-patterns and are in direct contact with the strip-shaped sub-patterns, and the orthographic projections of the modification patterns on the substrate and the orthographic projections of the strip-shaped sub-patterns corresponding to the modification patterns on the substrate are completely overlapped; the thin film transistor is a bottom gate thin film transistor, and the decoration pattern is directly contacted with a gate insulating layer arranged on one side, close to the substrate, of the insulating layer; or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor, and the modification pattern is directly contacted with a buffer layer arranged on one side of the insulating layer close to the substrate; the material of the modification pattern does not chemically react with the material of the insulating layer.
The embodiment of the invention provides a thin film transistor, a preparation method thereof and a display device, wherein the thin film transistor comprises an active pattern, the active pattern comprises a plurality of strip-shaped sub-patterns which are arranged at intervals, each strip-shaped sub-pattern comprises one or more carbon nanotubes, and the carbon nanotubes in each strip-shaped sub-pattern are limited in the area where the strip-shaped sub-pattern is located, so that the arrangement of the carbon nanotubes in one strip-shaped sub-pattern is limited. Compared with the area of the whole active pattern in the related art, the area of each strip-shaped sub-pattern in the embodiment of the invention is much smaller, so that compared with the arrangement of a plurality of carbon nano tubes along any direction in the related art, the included angle between the extending direction of the carbon nano tubes and the first direction is smaller, the included angle between the carbon nano tubes can be ignored, and the carbon nano tubes are regularly arranged as a whole, so that the problem of low mobility of the thin film transistor caused by the irregular arrangement of the carbon nano tubes in the related art can be solved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a display device according to an embodiment of the present invention;
fig. 2 is a schematic top view of a thin film transistor according to an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional view taken along line 1 of FIG. 2A-A;
fig. 4 is a schematic structural diagram of a thin film transistor according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a thin film transistor according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a thin film transistor according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of a thin film transistor according to an embodiment of the present invention;
FIG. 8a is a schematic view of a carbon nanotube arrangement provided in the related art;
fig. 8b is a schematic arrangement diagram of a carbon nanotube according to an embodiment of the present invention;
fig. 9 is a schematic structural diagram of an insulating layer according to an embodiment of the present invention;
fig. 10 is a schematic structural diagram of a thin film transistor according to an embodiment of the present invention;
fig. 11 is a schematic structural diagram of a thin film transistor according to an embodiment of the present invention;
fig. 12 is a schematic structural diagram of a thin film transistor according to an embodiment of the present invention;
fig. 13 is a schematic structural diagram of an array substrate according to an embodiment of the present invention;
fig. 14 is a schematic structural diagram of an array substrate according to an embodiment of the present invention;
Fig. 15 is a schematic flow chart of a process for manufacturing a thin film transistor according to an embodiment of the present invention;
fig. 16 is a schematic diagram of a process for manufacturing a thin film transistor according to an embodiment of the present invention;
fig. 17 is a schematic diagram of a process for manufacturing a thin film transistor according to an embodiment of the present invention.
Reference numerals:
1-a frame; 2-a display panel; 21-an array substrate; 22-a counter substrate; 3-a circuit board; 4-cover plate; 10-a substrate; 11-bar sub-pattern; 111-carbon nanotubes; 12-a source electrode; 13-a drain electrode; 14-an insulating layer; 141-a groove; 15-a gate; 16-a gate insulating layer; 17-a buffer layer; 18-an interlayer insulating layer; 19-an auxiliary gate; 20-modifying the pattern; 31-a drive transistor; 41-LED light emitting unit; 42-a first electrode; 43-a light-emitting layer; 44-a second electrode; 45-pixel definition layer.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The display device may be used as a mobile phone, a tablet computer, a Personal Digital Assistant (PDA), a vehicle-mounted computer, etc., and the specific application of the display panel is not particularly limited in the embodiments of the present invention.
As shown in fig. 1, the display device may include, for example, a frame 1, a display panel 2, a circuit board 3, a cover plate 4, and other electronic components including a camera and the like.
Taking the light emitting direction of the display panel 2 as top emission as an example, the frame 1 may be a U-shaped frame, and the display panel 2 and the circuit board 3 are disposed in the frame 1. The cover plate 4 is arranged on the light emitting side of the display panel 2, and the circuit board 3 is arranged on the side of the display panel 2 departing from the cover plate 4.
The display panel 2 may be an Organic Light Emitting Diode (OLED) display panel, a Light Emitting Diode (LED) display panel, a Quantum Dot Light Emitting Diodes (QLED) display panel, or a liquid crystal display panel.
Each of the display panels 2 includes an array substrate 21 and a counter substrate 22, and the array substrate 21 includes a thin film transistor.
Embodiments of the present invention provide a thin film transistor that can be used as a thin film transistor in the array substrate 21 described above. Of course, the thin film transistor may also be used for other substrates, and the embodiment of the present invention is not particularly limited.
As shown in fig. 2, 3 and 16, the thin film transistor includes an insulating layer 14 disposed on a substrate 10, an active pattern including a carbon nano-hanger, a source electrode 12 and a drain electrode 13; the active pattern includes a plurality of bar-shaped sub-patterns 11 extending in a first direction and arranged at intervals; in the first direction, one end of each of the bar-shaped sub-patterns 11 in the active pattern is in contact with the source electrode 12 and the other end is in contact with the drain electrode 13; the insulating layer 14 includes a plurality of stripe-shaped grooves 141, the grooves 141 correspond to the stripe-shaped sub-patterns 11 one to one, and an orthogonal projection of the grooves 141 on the substrate 10 completely overlaps an orthogonal projection of the stripe-shaped sub-patterns 11 on the substrate 10.
Alternatively, the thin film transistor may be a bottom gate type thin film transistor, a top gate type thin film transistor, or a double gate type thin film transistor.
As shown in fig. 4 and 5, if the thin film transistor is a bottom gate thin film transistor, the bottom gate thin film transistor further includes a gate electrode 15 and a gate insulating layer 16 sequentially disposed on the substrate 10. Wherein, the gate electrode 15 and the gate insulating layer 16 are disposed on the side of the active pattern close to the substrate 10.
As shown in fig. 6, if the thin film transistor is a top gate thin film transistor, the top gate thin film transistor further includes a gate insulating layer 16, a gate electrode 15, and an interlayer insulating layer 18 sequentially disposed on a side of the active pattern away from the substrate 10. Wherein, the gate insulating layer 16, the gate electrode 15, and the interlayer insulating layer 18 are disposed on the source and drain electrodes 12 and 13 near the substrate 10, and the source and drain electrodes 12 and 13 are in contact with the active pattern through via holes.
As shown in fig. 7, if the thin film transistor is a dual gate type thin film transistor, the dual gate type thin film transistor further includes a gate insulating layer 16, a gate electrode 15, an interlayer insulating layer 18, and an auxiliary gate electrode 19, which are sequentially disposed on a side of the active pattern away from the substrate 10. Wherein, the gate insulating layer 16, the gate electrode 15, and the interlayer insulating layer 18 are disposed on the source and drain electrodes 12 and 13 near the substrate 10, and the source and drain electrodes 12 and 13 are in contact with the active pattern through via holes. The auxiliary gate 19 is disposed on a side of the interlayer insulating layer 18 facing away from the substrate 10, and is electrically connected to the gate 15 through a via hole in the interlayer insulating layer 18.
Alternatively, since the bar-shaped sub-patterns 11 extend in the first direction, and in the first direction, one end of each of the bar-shaped sub-patterns 11 in the active pattern is in contact with the source electrode 12 and the other end is in contact with the drain electrode 13. Thus, the first direction, i.e. the direction in which the source 12 points towards the drain 13.
Here, each of the bar-shaped sub-patterns 11 has opposite ends in the first direction, and thus, it is clear and unique that one end of the bar-shaped sub-pattern 11 is in contact with the source electrode 12 and the other end is in contact with the drain electrode 13.
Optionally, since the carbon nanotubes in the embodiment of the present invention are used as the active pattern, the carbon nanotubes used in the embodiment of the present invention are semiconductor type carbon nanotubes.
Here, the carbon nanotube raw material includes a metallic type carbon nanotube and a semiconductor type carbon nanotube. According to the embodiment of the invention, the metal type carbon nano tube in the carbon nano tube raw material can be removed by adopting a centrifugal mode and the like so as to obtain the semiconductor type carbon nano tube.
Illustratively, the metal-type carbon nanotubes in the carbon nanotube raw material are removed by centrifugation. The polymer can be added into the carbon nano tube raw material; a plurality of semiconductor type carbon nanotubes and metal type carbon nanotubes in the carbon nanotubes are dispersed into independent individuals by adopting an ultrasonic dispersion mode, and a polymer reacts with the semiconductor type carbon nanotubes and wraps the surfaces of the semiconductor type carbon nanotubes to avoid any one semiconductor type carbon nanotube from contacting with the metal type carbon nanotubes and other semiconductor type carbon nanotubes; and then separating the semiconductor type carbon nano tube by adopting a centrifugal process according to the density difference of the semiconductor type carbon nano tube and the metal type carbon nano tube.
In addition, the polymer on the surface of the semiconductor carbon nanotube can be removed, for example, the polymer on the surface of the semiconductor carbon nanotube can be removed by using a solvent.
Alternatively, the number of the bar sub-patterns 11 in the active pattern is not limited. The number of the bar-shaped sub-patterns 11 in the active pattern is related to the size of the source and drain electrodes 12 and 13 and the width of the cross section of each bar-shaped sub-pattern 11.
Wherein a cross section of the stripe-shaped sub-pattern 11 is a section in a direction perpendicular to a thickness direction of the substrate 10. The width of the cross section of the bar-shaped sub-pattern 11 is perpendicular to the first direction.
Alternatively, the plurality of bar-shaped sub-patterns 11 in the active pattern may be the same or different in size.
Alternatively, one skilled in the art will appreciate that the carbon nanotubes may be approximately shaped as cylinders. The carbon nanotubes have a diameter (diameter of the bottom surface of the cylinder) of about 1nm and a length (height of the cylinder) of about 1000 nm.
The width range of the cross section of the plurality of bar-shaped sub-patterns 11 is not limited by the embodiment of the present invention. The width of the cross section of each bar-shaped sub-pattern 11 should be at least greater than or equal to the diameter of one carbon nanotube and less than the length of the carbon nanotube to realize the arrangement of a plurality of carbon nanotubes.
Illustratively, the width of the cross section of the stripe-shaped sub-pattern 11 ranges from 1nm or more to less than 1000 nm.
The size of the bar-shaped sub-pattern 11 in the first direction is not limited, and the size of the bar-shaped sub-pattern 11 in the first direction is related to the spacing between the source and drain electrodes 12 and 13, and the size of the carbon nanotube.
Optionally, the material of the source electrode 12 and the drain electrode 13 may include metal materials such as molybdenum (Mo), copper (Cu), molybdenum-niobium alloy (MoNb), and aluminum (Al); the material of the source electrode 12 and the drain electrode 13 may also include Indium Tin Oxide (ITO) or other transparent conductive material.
The material of the gate 15 may include metal materials such as Mo, Cu, MoNb, Al, etc.; the material of the gate electrode 15 may also include ITO or the like transparent conductive material.
The source electrode 12, the drain electrode 13, and the gate electrode 15 may be a single layer or a multilayer. For example, the source electrode 12, the drain electrode 13, and the gate electrode 15 include one layer, and the material is copper; alternatively, the source electrode 12, the drain electrode 13, and the gate electrode 15 include two layers, one of which is made of chromium (Cr) and the other of which is made of gold (Au).
Alternatively, as shown in fig. 4 to 7, the surface of the stripe-shaped sub-pattern 11 near the side of the substrate 10 is flush with the bottom surface of the groove 141 corresponding thereto. That is, the bar-shaped sub-patterns 11 are directly formed in the grooves 141 corresponding thereto. Here, the bottom surface of the groove 141, i.e., the surface of the groove 141 near the substrate 10.
The thickness of the bar-shaped sub-pattern 11 is less than or equal to the depth of the groove 141 corresponding thereto; alternatively, the distance between the surface of the stripe-shaped sub-pattern 11 facing away from the substrate 10 and the substrate 10 is greater than the distance between the surface of the insulating layer 14 on the side facing away from the substrate 10 and the substrate 10.
Alternatively, as shown in fig. 10 to 12, other structures (for example, the following modification pattern, for convenience of description, the other structures are referred to as modification patterns later) are disposed in the groove 141, and the modification pattern 20 is disposed on a side of the bar-shaped sub-pattern 11 close to the substrate 10.
Here, the thickness of the decoration pattern 20 is smaller than the depth of the groove 141 corresponding thereto. As shown in fig. 10, when the sum of the thicknesses of the modification pattern 20 and the bar-shaped sub-pattern 11 is greater than the depth of the corresponding groove 141, a part of the bar-shaped sub-pattern 11 is filled in the corresponding groove 141, and another part is higher than the surface of the insulating layer 14 away from the substrate 10; alternatively, in the case where the sum of the thicknesses of the decoration pattern 20 and the bar-shaped sub-pattern 11 is less than or equal to the depth of the groove 141 corresponding thereto, the bar-shaped sub-pattern 11 is completely filled in the groove 141 corresponding thereto.
Alternatively, as shown in fig. 11 and 12, the thickness of the modification pattern 20 is greater than or equal to the depth of the corresponding groove 141, and the bar-shaped sub-patterns 11 are all higher than the surface of the insulating layer 14 away from the substrate 10.
As described above, the groove 141 may or may not penetrate the insulating layer 14. The thickness direction of the stripe-shaped sub-pattern 11, the thickness direction of the decoration pattern 20, and the depth direction of the groove 141 are all parallel to the thickness direction of the substrate 10. The depth of the groove 141 at each position may be the same or different. The embodiment of the present invention compares the maximum depth of the groove 141 with the maximum thickness of the bar-shaped sub-pattern 11 or the maximum thickness of the decoration pattern 20.
In the related art, the carbon nanotube may be used as a material of the active pattern to solve the problems of poor uniformity, difficulty in implementing a large-sized display panel, low mobility, and the like. However, as shown in fig. 8a, the plurality of carbon nanotubes 111 in the active pattern manufactured by the conventional process are arranged in disorder. However, if the carbon nanotubes 111 arranged in a disordered manner are used as the active pattern, the mobility of the thin film transistor is still low.
The embodiment of the invention provides a thin film transistor which comprises an active pattern, wherein the active pattern comprises a plurality of strip-shaped sub-patterns 11 arranged at intervals, and each strip-shaped sub-pattern 11 comprises one or more carbon nano tubes 111. The carbon nanotubes 111 in each of the bar-shaped sub-patterns 11 are confined within the area where the bar-shaped sub-patterns 11 are located, and thus, the arrangement of the carbon nanotubes 111 in one bar-shaped sub-pattern 11 is limited. Compared with the area of the whole active pattern in the related art, the area of each stripe sub-pattern 11 in the embodiment of the present invention is much smaller, and therefore, compared with the arrangement of the plurality of carbon nanotubes 111 along any direction in the related art, the included angle between the extending direction of the carbon nanotubes 111 and the first direction in the embodiment of the present invention is smaller (as shown in fig. 8 b), and further the included angle between the plurality of carbon nanotubes 111 is negligible, and the plurality of carbon nanotubes 111 are regularly arranged as a whole, so that the problem of low mobility of the thin film transistor caused by the irregular arrangement of the plurality of carbon nanotubes 111 in the related art can be improved.
Alternatively, as shown in fig. 4 and 6, the thickness of the bar-shaped sub-pattern 11 is exactly equal to the depth of the groove 141 corresponding thereto.
Alternatively, as shown in fig. 5 and 7, the thickness of the bar-shaped sub-pattern 11 is smaller than the depth of the groove 141 corresponding thereto.
Alternatively, the distance between the surface of the stripe-shaped sub-pattern 11 facing away from the substrate 10 and the substrate 10 is larger than the distance between the surface of the insulating layer 14 facing away from the substrate 10 and the substrate 10.
In the embodiment of the present invention, the insulating layer 14 having the groove 141 may be formed on the substrate 10; after that, the bar-shaped sub-patterns 11 are directly formed in the grooves 141 to obtain a plurality of bar-shaped sub-patterns 11 arranged at intervals.
Alternatively, as shown in fig. 10 to 12, the groove 141 penetrates the insulating layer 14; each groove 141 is filled with a decoration pattern 20; the active pattern is arranged on the side of the modified pattern 20 away from the substrate 10; the modification patterns 20 are in one-to-one correspondence with the strip-shaped sub-patterns 11 and are in direct contact with the strip-shaped sub-patterns 11, and the orthographic projection of the modification patterns 20 on the substrate 10 and the orthographic projection of the corresponding strip-shaped sub-patterns 11 on the substrate 10 are completely overlapped; wherein the material of the modification pattern 20 does not chemically react with the material of the insulating layer 14.
Alternatively, the material of the modification pattern 20 is not limited. On one hand, the material of the modification pattern 20 may chemically react with the carbon nanotubes 111, so that the bar-shaped sub-patterns 11 are formed only on the modification pattern 20; on the other hand, in the case where the groove 141 penetrates the insulating layer 14, the material of the modification pattern 20 does not chemically react with the material of the insulating layer 14, so as to prevent the modification pattern 20 from being formed on the surface of the insulating layer 14 on the side away from the substrate 10, and further prevent the active pattern from being formed in a region other than the region where the groove 141 is located.
Alternatively, as shown in fig. 10, the thickness of the decoration pattern 20 is smaller than the depth of the groove 141 corresponding thereto.
Alternatively, as shown in fig. 11 and 12, the thickness of the decoration pattern 20 is just equal to the depth of the groove 141 corresponding thereto.
Alternatively, the thickness of the decoration pattern 20 is greater than the depth of the groove 141 corresponding thereto.
In the embodiment of the present invention, the modification pattern 20 is formed in the groove 141, and then the bar-shaped sub-pattern 11 is formed on the side of the modification pattern 20 away from the substrate 10. Since the material of the modification pattern 20 does not chemically react with the material of the insulating layer 14, the modification pattern 20 is formed only in the groove 141; since the material of the modification pattern 20 can chemically react with the carbon nanotubes 111, the modification pattern 20 can firmly adsorb and fix the carbon nanotubes 111, so that the bar-shaped sub-patterns 11 are formed only on the modification pattern 20. The plurality of bar-shaped sub-patterns 11 in the resulting active pattern are arranged at intervals from each other, and an orthogonal projection of each bar-shaped sub-pattern 11 on the substrate 10 and an orthogonal projection of its corresponding groove 141 on the substrate 10 exactly overlap completely.
Optionally, as shown in fig. 4, the thin film transistor is a bottom gate thin film transistor; the groove 141 does not penetrate the insulating layer 14, and the insulating layer 14 is a gate insulating layer 16.
Here, in the case where the thin film transistor is a bottom gate type thin film transistor, the thin film transistor may further include a buffer layer 17 disposed between the substrate 10 and the gate electrode 15.
Optionally, as shown in fig. 6, the thin film transistor is a top gate thin film transistor or a dual gate thin film transistor (fig. 6 only shows the top gate thin film transistor); the thin film transistor also comprises a buffer layer 17 arranged on the substrate 10, wherein the buffer layer 17 is arranged on one side of the active pattern close to the substrate 10; the groove 141 does not penetrate the insulating layer 14, and the insulating layer 14 is a buffer layer 17.
In the embodiment of the present invention, in the case that the groove 141 does not penetrate through the insulating layer 14, if the thin film transistor is a bottom gate thin film transistor, the gate insulating layer 16 may be used as the insulating layer 14 in common; if the thin film transistor is a top gate type thin film transistor or a double gate type thin film transistor, the buffer layer 17 may be used in common as the insulating layer 14. Therefore, the preparation process of the thin film transistor can be simplified, and the cost can be saved.
Optionally, as shown in fig. 5, the thin film transistor is a bottom gate thin film transistor; the gate insulating layer 16 is disposed on a side of the insulating layer 14 adjacent to the substrate 10. Alternatively, as shown in fig. 7, the thin film transistor is a top gate thin film transistor or a dual gate thin film transistor; the thin film transistor further comprises a buffer layer 17 arranged on the substrate 10, wherein the buffer layer 17 is arranged on one side of the insulating layer 14 close to the substrate 10.
Alternatively, the groove 141 may or may not penetrate the insulating layer 14. Fig. 5 and 7 show only the case where the groove 141 penetrates the insulating layer 14.
In an embodiment of the present invention, the insulating layer 14 may be disposed at different positions for different types of thin film transistors.
Optionally, as shown in fig. 10, the thin film transistor is a bottom gate thin film transistor; the gate insulating layer 16 is disposed on a side of the insulating layer 14 close to the substrate 10, and the modification pattern 20 is in direct contact with the gate insulating layer 16.
Alternatively, the material of the modification pattern 20 may chemically react with the material of the gate insulating layer 16 so that the modification pattern 20 is in direct contact with the gate insulating layer 16.
Here, the material of the modification pattern 20 may be an amphoteric coupling agent. Wherein one group of the amphoteric coupling agent chemically reacts with the carbon nanotube 111 and the other group chemically reacts with the material of the gate insulating layer 16.
Illustratively, the amphoteric coupling agent is a silane coupling agent, for example,3-Aminopropyltriethoxysilane (APTES). The material of the gate insulating layer 16 is silicon oxide (SiO)x) Hafnium oxide (HfO)2) Or magnesium oxide (MgO) and HfO2The composite film layer of (1). The material of the insulating layer 14 is a hydrophobic type insulating material such as silicon nitride (SiN) x)。
Wherein the silane coupling agent comprises an amino group and a carboxyl group. The carboxyl group and the material of the gate insulating layer 16 are condensed to form a self-assembled monolayer; the amino group chemically reacts with the carbon nanotube 111 and is adsorbed on the surface of the modification pattern 20.
Alternatively, as shown in fig. 11 and 12, the thin film transistor is a top gate thin film transistor or a dual gate thin film transistor; the buffer layer 17 is disposed on one side of the insulating layer 14 close to the substrate 10, and the modification pattern 20 is in direct contact with the buffer layer 17.
Alternatively, the material of the modification pattern 20 may chemically react with the material of the buffer layer 17, so that the modification pattern 20 is in direct contact with the buffer layer 17.
Here, the material of the modification pattern 20 may be an amphoteric coupling agent. Wherein one group of the amphoteric coupling agent chemically reacts with the carbon nanotube 111, and the other group chemically reacts with the material of the buffer layer 17.
Illustratively, the amphoteric coupling agent is a silane coupling agent, e.g., APTES. The buffer layer 17 is made of SiOx、HfO2Or MgO and HfO2The composite film layer of (1). The material of the insulating layer 14 is a hydrophobic type insulating material, such as SiNx。
Wherein the silane coupling agent comprises an amino group and a carboxyl group. The carboxyl and the material of the buffer layer 17 are condensed to form a self-assembled monomolecular layer; the amino group chemically reacts with the carbon nanotube 111 and is adsorbed on the surface of the modification pattern 20.
In the embodiment of the present invention, in the case that the groove 141 penetrates the insulating layer 14, if the thin film transistor is a bottom gate thin film transistor, the material of the modification pattern 20 and the material of the gate insulating layer 16 may chemically react to fix the modification pattern 20 on the gate insulating layer 16; if the thin film transistor is a top gate thin film transistor or a dual gate thin film transistor, the material of the modification pattern 20 and the material of the buffer layer 17 may be chemically reacted to fix the modification pattern 20 on the buffer layer 17.
Alternatively, as shown in fig. 8b, the width of the cross section of the stripe-shaped sub-pattern 11 ranges from greater than or equal to 500nm to less than 1000 nm.
Illustratively, the widths of the cross sections of the stripe sub-patterns 11 are 500nm, 655nm, 1000 nm.
Since the carbon nanotube 111 has a diameter of about 1nm and a length of about 1000nm, the length of the carbon nanotube 111 is much greater than its diameter.
Based on this, in the embodiment of the present invention, since the length of the carbon nanotube 111 is much larger than the diameter thereof, the smaller the width of the cross section of the bar-shaped sub-pattern 11 is, the smaller the angle between each carbon nanotube 111 and the first direction is. In the embodiment of the invention, the carbon nanotubes 111 are limited in the area with the width range of more than or equal to 500nm and less than 1000nm, so that the included angle between each carbon nanotube 111 and the first direction is smaller, and the included angles among the plurality of carbon nanotubes 111 can be ignored, thereby improving the mobility of the thin film transistor.
An embodiment of the present invention further provides a display device, including an array substrate 21, as shown in fig. 13 and 14, the array substrate 21 includes a pixel circuit, and the pixel circuit includes a driving transistor 31; the driving transistor 31 is a thin film transistor according to any of the embodiments.
On the basis, the pixel circuit further comprises a switching transistor and a storage capacitor. The switching transistor may be a thin film transistor as described in any of the previous embodiments, or the switching transistor may be a related art thin film transistor.
Here, taking the pixel circuit of 2T1C as an example, the pixel circuit includes at least one switching transistor, one driving transistor 31, and one storage capacitor. The source 12 of the switching transistor is connected to the data signal terminal, and the drain 13 is connected to the gate 15 of the driving transistor 31 and one end of the storage capacitor. The source 12 of the driving transistor 31 is connected to a VDD signal line or a signal terminal, and the drain 13 is connected to the other end of the storage capacitor and one end of a light emitting device (e.g., a first electrode or an LED light emitting unit hereinafter). The other end of the light emitting device is connected to a VSS signal line or a signal terminal.
Alternatively, the display device may be an OLED display device, or a QLED display device, or an LED display device.
As shown in fig. 13, in the case that the display device is an OLED display device or a QLED display device, the OLED display device or the QLED display device includes an array substrate 21, the array substrate 21 further includes a plurality of light emitting devices disposed on a side of the thin film transistor facing away from the substrate 10, the light emitting devices include a first electrode 42, a light emitting layer 43, and a second electrode 44, which are sequentially stacked, and the first electrode 42 is electrically connected to the drain 13 of the driving transistor 31. On this basis, the array substrate 21 further includes a pixel defining layer 45 disposed between adjacent light emitting devices.
Wherein the first electrode 42 is an anode and the second electrode 44 is a cathode; alternatively, the first electrode 42 is a cathode and the second electrode 44 is an anode.
If the display device is an OLED display device, the light-emitting layer 43 is an organic light-emitting functional layer; if the display device is a QLED display device, the light-emitting layer 43 is a quantum dot light-emitting layer.
As shown in fig. 14, in the case where the display device is an LED display device, the array substrate 21 further includes an LED light emitting unit 41 disposed on a side of the thin film transistor facing away from the substrate 10, the LED light emitting unit 41 is electrically connected to the drain 13 of the driving transistor 31, and a cathode of the LED light emitting unit 41 is connected to a VSS signal line or a signal terminal.
Embodiments of the present invention provide a display device, in which the driving transistor 31 generally requires higher mobility, so that the thin film transistor of the embodiments of the present invention can be used as the driving transistor 31 to improve the light emitting efficiency.
The embodiment of the invention also provides a preparation method of the thin film transistor, which can be realized by the following steps as shown in fig. 15:
s11, as shown in fig. 16, an insulating film is formed on the substrate 10, and a plurality of stripe-shaped grooves 141 extending in the first direction and arranged at intervals are formed in the insulating film to obtain the insulating layer 14.
Alternatively, as shown in fig. 9, the distance between the surface of the other portion of the insulating layer 14 except the groove 141 on the side facing away from the substrate 10 and the substrate 10 is the same regardless of whether one or more thin film transistors are provided on the substrate 10.
Alternatively, the insulating layer may be formed in a different manner depending on the material of the insulating layer 14.
For example, if the material of the insulating layer 14 includes an inorganic insulating material or a photosensitive material, the insulating layer 14 including the plurality of grooves 141 may be formed using a photolithography process.
S12, as shown in fig. 17, forming an active pattern including carbon nanotubes on the side of the insulating layer 14 facing away from the substrate 10; the active pattern includes a plurality of bar-shaped sub-patterns 11 arranged at intervals; the stripe-shaped sub-patterns 11 are in one-to-one correspondence with the grooves 141, and an orthographic projection of the stripe-shaped sub-patterns 11 on the substrate 10 and an orthographic projection of the grooves 141 corresponding thereto on the substrate 10 are completely overlapped.
Alternatively, since the bar-shaped sub-patterns 11 extend in the first direction, and in the first direction, one end of each of the bar-shaped sub-patterns 11 in the active pattern is in contact with the source electrode 12 and the other end is in contact with the drain electrode 13. Thus, the first direction, i.e., the direction in which the source 12 to be formed points toward the drain 13.
Here, each of the bar-shaped sub-patterns 11 has opposite ends in the first direction, and thus, it is clear and unique that one end of the bar-shaped sub-pattern 11 is in contact with the source electrode 12 and the other end is in contact with the drain electrode 13.
Optionally, since the carbon nanotube 111 in the embodiment of the present invention is used as an active pattern, the carbon nanotube 111 adopted in the embodiment of the present invention is a semiconductor type carbon nanotube.
Here, the carbon nanotube raw material includes a metallic type carbon nanotube and a semiconductor type carbon nanotube. According to the embodiment of the invention, the metal type carbon nano tube in the carbon nano tube raw material can be removed by adopting the modes of centrifugation, filtration and the like so as to obtain the semiconductor type carbon nano tube.
Illustratively, the metal-type carbon nanotubes in the carbon nanotube raw material are removed by centrifugation. The polymer can be added into the carbon nano tube raw material; a plurality of semiconductor type carbon nanotubes and metal type carbon nanotubes in the carbon nanotubes are dispersed into independent individuals by adopting an ultrasonic dispersion mode, and a polymer reacts with the semiconductor type carbon nanotubes and wraps the surfaces of the semiconductor type carbon nanotubes to avoid any one semiconductor type carbon nanotube from contacting with the metal type carbon nanotubes and other semiconductor type carbon nanotubes; and then separating the semiconductor type carbon nano tube by adopting a centrifugal process according to the density difference of the semiconductor type carbon nano tube and the metal type carbon nano tube.
In addition, the polymer on the surface of the semiconductor carbon nanotube can be removed, for example, the polymer on the surface of the semiconductor carbon nanotube can be removed by using a solvent.
Alternatively, the number of the bar sub-patterns 11 in the active pattern is not limited. The number of the bar-shaped sub-patterns 11 in the active pattern is related to the size of the source and drain electrodes 12 and 13 to be formed and the width of the cross section of each bar-shaped sub-pattern 11.
Alternatively, the plurality of bar-shaped sub-patterns 11 in the active pattern may be the same or different in size.
Alternatively, one skilled in the art will appreciate that the carbon nanotubes 111 may be approximately shaped as cylinders. The carbon nanotube 111 has a diameter (diameter of the bottom surface of the cylinder) of about 1nm and a length (height of the cylinder) of about 1000 nm.
The width range of the cross section of the plurality of bar-shaped sub-patterns 11 is not limited by the embodiment of the present invention. The width of the cross section of each bar-shaped sub-pattern 11 should be at least greater than or equal to the diameter of one carbon nanotube 111 and less than the length of the carbon nanotube to realize the alignment of the plurality of carbon nanotubes.
Illustratively, the width of the cross section of the stripe-shaped sub-pattern 11 ranges from 1nm or more to less than 1000 nm.
The size of the bar-shaped sub-pattern 11 in the first direction is not limited, and the size of the bar-shaped sub-pattern 11 in the first direction is related to the spacing between the source and drain electrodes 12 and 13, and the size of the carbon nanotube 111.
Alternatively, the manner of forming the active pattern is not limited.
As an example, the carbon nanotube 111 solution may be formed on the substrate 10 by spray coating, spin coating, doctor blading, inkjet printing, or the like; and then, drying the carbon nanotube 111 solution at high temperature to obtain the carbon nanotube film.
If the carbon nanotube solution is formed in the groove 141 by spraying, spin coating, blade coating, or the like, after the carbon nanotube film is obtained, a photoresist is formed on the side of the carbon nanotube film away from the substrate 10; exposing and developing the photoresist to form a photoresist pattern; and finally, etching the carbon nanotube film to obtain the active pattern, and stripping the photoresist pattern.
If the carbon nanotube solution is formed by adopting an ink-jet printing mode, the obtained carbon nanotube film is the active pattern.
S13, referring to fig. 4 to 7, a source electrode 12 and a drain electrode 13 are formed on a side of the active pattern facing away from the substrate 10, and one end of each of the bar-shaped sub-patterns 11 in the active pattern is in contact with the source electrode 12 and the other end is in contact with the drain electrode 13 in the first direction.
Optionally, the material of the source electrode 12 and the drain electrode 13 may include metal materials such as Mo, Cu, MoNb, and Al; the material of the source electrode 12 and the drain electrode 13 may also include ITO or the like transparent conductive material.
The source electrode 12 and the drain electrode 13 may be a single layer or a multilayer. For example, the source electrode 12 and the drain electrode 13 include one layer, and the material is copper; alternatively, the source electrode 12 and the drain electrode 13 include two layers, one of which is Cr and the other of which is Au.
Embodiments of the present invention provide a method for manufacturing a thin film transistor, which has the same technical effects as the thin film transistor described above, and are not described herein again.
Alternatively, as shown in fig. 10 to 12, the groove 141 penetrates the insulating layer 14; after the insulating layer 14 is formed and before the active pattern is formed, the method for manufacturing a thin film transistor further includes: filling a decoration pattern 20 into each groove 141; the modification patterns 20 are disposed on one side of the active pattern close to the substrate 10, the modification patterns 20 correspond to the bar-shaped sub-patterns 11 one by one and are in direct contact with each other, and an orthographic projection of the modification pattern 20 on the substrate 10 and an orthographic projection of the corresponding bar-shaped sub-pattern 11 on the substrate 10 are completely overlapped. As shown in fig. 10, the thin film transistor is a bottom gate thin film transistor, and the modification pattern 20 is in direct contact with the gate insulating layer 16 disposed on the insulating layer 14 near the substrate 10; alternatively, as shown in fig. 11 and 12, the thin film transistor is a top gate thin film transistor or a dual gate thin film transistor, and the modification pattern 20 is in direct contact with the buffer layer 17 provided on the side of the insulating layer 14 close to the substrate 10. The material of the modification pattern 20 does not chemically react with the material of the insulating layer 14.
Alternatively, the material of the modification pattern 20 is not limited. On one hand, the material of the modification pattern 20 may chemically react with the carbon nanotubes 111, so that the bar-shaped sub-patterns 11 are formed only on the modification pattern 20; on the other hand, in the case that the groove 141 penetrates the insulating layer 14, the material of the modification pattern 20 does not chemically react with the material of the insulating layer 14, so as to prevent the modification pattern 20 from being formed on the surface of the insulating layer 14 on the side away from the substrate 10, and further prevent the active pattern from being formed in a region other than the region where the groove 141 is located; on the other hand, if the thin film transistor is a bottom gate thin film transistor, the material of the modification pattern 20 may also chemically react with the material of the gate insulating layer 16, so that the modification pattern 20 is fixed on the gate insulating layer 16; alternatively, if the thin film transistor is a top gate thin film transistor or a dual gate thin film transistor, the material of the modification pattern 20 may also chemically react with the material of the buffer layer 17, so that the modification pattern 20 is fixed on the buffer layer 17.
Here, the material of the modification pattern 20 may be an amphoteric coupling agent. Wherein one group of the amphoteric coupling agent chemically reacts with the carbon nanotube 111, and the other group chemically reacts with the material of the gate insulating layer 16 (or the buffer layer).
Illustratively, the amphoteric coupling agent is a silane coupling agent, e.g., APTES. The material of the gate insulating layer 16 is SiOx、HfO2Or MgO and HfO2The composite film layer of (1). The material of the insulating layer 14 (or buffer layer) is a hydrophobic type insulating material, such as SiNx。
Wherein the silane coupling agent comprises an amino group and a carboxyl group. The carboxyl group and the material of the gate insulating layer 16 (or the buffer layer) are condensed to form a self-assembled monolayer; the amino group chemically reacts with the carbon nanotube 111 and is adsorbed on the surface of the modification pattern 20.
Alternatively, as shown in fig. 10, the thickness of the decoration pattern 20 is smaller than the depth of the groove 141 corresponding thereto.
Alternatively, as shown in fig. 11 and 12, the thickness of the decoration pattern 20 is just equal to the depth of the groove 141 corresponding thereto.
Alternatively, the thickness of the decoration pattern 20 is greater than the depth of the groove 141 corresponding thereto.
In the embodiment of the present invention, the modification pattern 20 is formed in the groove 141, and then the bar-shaped sub-pattern 11 is formed on the side of the modification pattern 20 away from the substrate 10. Since the material of the modification pattern 20 does not chemically react with the material of the insulating layer 14, the modification pattern 20 is formed only in the groove 141; since the material of the modification pattern 20 can chemically react with the carbon nanotubes 111, the modification pattern 20 can firmly adsorb and fix the carbon nanotubes 111, so that the bar-shaped sub-patterns 11 are formed only on the modification pattern 20. Meanwhile, in the case where the groove 141 penetrates the insulating layer 14, if the thin film transistor is a bottom gate thin film transistor, the material of the modification pattern 20 may chemically react with the material of the gate insulating layer 16 to fix the modification pattern 20 on the gate insulating layer 16; if the thin film transistor is a top gate thin film transistor or a dual gate thin film transistor, the material of the modification pattern 20 and the material of the buffer layer 17 may be chemically reacted to fix the modification pattern 20 on the buffer layer 17.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (11)

1. A thin film transistor includes an insulating layer disposed on a substrate, an active pattern including carbon nanotubes, a source electrode and a drain electrode;
the active pattern comprises a plurality of strip-shaped sub-patterns which extend along a first direction and are arranged at intervals; along the first direction, one end of each strip-shaped sub-pattern in the active pattern is in contact with the source electrode, and the other end of each strip-shaped sub-pattern in the active pattern is in contact with the drain electrode;
the insulating layer comprises a plurality of strip-shaped grooves, the grooves correspond to the strip-shaped sub-patterns one to one, and the orthographic projections of the grooves on the substrate are completely overlapped with the orthographic projections of the strip-shaped sub-patterns on the substrate.
2. The thin film transistor of claim 1, wherein the stripe sub-patterns are filled in the groove;
The surface of one side, close to the substrate, of the strip-shaped sub-pattern is flush with the bottom surface of the groove corresponding to the strip-shaped sub-pattern.
3. The thin film transistor according to claim 1, wherein the groove penetrates the insulating layer;
each groove is filled with a decorative pattern;
the active pattern is arranged on one side, away from the substrate, of the modification pattern; the modification patterns are in one-to-one correspondence with the strip-shaped sub-patterns and are in direct contact with the strip-shaped sub-patterns, and the orthographic projection of the modification patterns on the substrate and the orthographic projection of the corresponding strip-shaped sub-patterns on the substrate are completely overlapped;
wherein the material of the modification pattern does not chemically react with the material of the insulating layer.
4. The thin film transistor according to claim 2,
the thin film transistor is a bottom gate thin film transistor; the insulating layer is arranged on one side, close to the substrate, of the active pattern; the groove does not penetrate through the insulating layer;
or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor; the insulating layer is arranged on one side, close to the substrate, of the active pattern; the groove does not penetrate through the insulating layer.
5. The thin film transistor according to claim 2 or 3,
the thin film transistor is a bottom gate thin film transistor; the thin film transistor also comprises a gate insulating layer arranged on the substrate, and the gate insulating layer is arranged on one side, close to the substrate, of the insulating layer;
or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor; the thin film transistor further comprises a buffer layer arranged on the substrate, and the buffer layer is arranged on one side, close to the substrate, of the insulating layer.
6. The thin film transistor according to claim 3,
the thin film transistor is a bottom gate thin film transistor; the thin film transistor also comprises a gate insulating layer arranged on the substrate, the gate insulating layer is arranged on one side, close to the substrate, of the insulating layer, and the modification pattern is in direct contact with the gate insulating layer;
or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor; the thin film transistor further comprises a buffer layer arranged on the substrate, the buffer layer is arranged on one side, close to the substrate, of the insulating layer, and the decoration pattern is in direct contact with the buffer layer.
7. The thin film transistor according to claim 6, wherein a material of the modification pattern is an amphoteric coupling agent, the amphoteric coupling agent is a silane coupling agent, and a material of the insulating layer is a hydrophobic insulating material;
the material of the gate insulating layer in the bottom gate type thin film transistor can chemically react with carboxyl; alternatively, the material of the buffer layer in the top gate thin film transistor or the double gate thin film transistor may chemically react with a carboxyl group.
8. The thin film transistor according to any one of claims 1 to 3, wherein a width of a cross section of the stripe-shaped sub-pattern ranges from 500nm or more to less than 1000 nm;
wherein the cross section is perpendicular to a thickness direction of the substrate, and a width of the cross section is perpendicular to the first direction.
9. A display device comprises an array substrate, wherein the array substrate comprises a pixel circuit, and the pixel circuit comprises a driving transistor;
the driving transistor is the thin film transistor according to any one of claims 1 to 8.
10. A method for manufacturing a thin film transistor includes:
forming an insulating film on a substrate, and forming a plurality of strip-shaped grooves which extend along a first direction and are arranged at intervals in the insulating film to obtain an insulating layer;
Forming an active pattern comprising carbon nanotubes on one side of the insulating layer, which is far away from the substrate; the active pattern comprises a plurality of strip-shaped sub-patterns which are arranged at intervals, the strip-shaped sub-patterns correspond to the grooves one to one, and the orthographic projections of the strip-shaped sub-patterns on the substrate are completely overlapped with the orthographic projections of the grooves corresponding to the strip-shaped sub-patterns on the substrate;
and forming a source electrode and a drain electrode on one side of the active pattern, which is far away from the substrate, wherein one end of each strip-shaped sub-pattern in the active pattern is in contact with the source electrode, and the other end of each strip-shaped sub-pattern in the active pattern is in contact with the drain electrode along the first direction.
11. The method for manufacturing a thin film transistor according to claim 10, wherein the groove penetrates the insulating layer;
after the insulating layer is formed and before the active pattern is formed, the method for manufacturing a thin film transistor further includes:
filling a decorative pattern into each groove; the modification patterns are arranged on one side, close to the substrate, of the active pattern, the modification patterns are in one-to-one correspondence with the strip-shaped sub-patterns and are in direct contact with the strip-shaped sub-patterns, and the orthographic projections of the modification patterns on the substrate and the orthographic projections of the strip-shaped sub-patterns corresponding to the modification patterns on the substrate are completely overlapped;
The thin film transistor is a bottom gate thin film transistor, and the decoration pattern is directly contacted with a gate insulating layer arranged on one side, close to the substrate, of the insulating layer; or the thin film transistor is a top gate type thin film transistor or a double-gate type thin film transistor, and the modification pattern is directly contacted with a buffer layer arranged on one side of the insulating layer close to the substrate;
the material of the modification pattern does not chemically react with the material of the insulating layer.
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