A metal oxide semiconductor thin film and a thin film transistor

Abstract

The application discloses a metal oxide semiconductor thin film and a thin film transistor. The semiconductor thin film comprises a laminated structure of at least one high-mobility metal oxide semiconductor thin film and at least one photo-generated carrier quenching metal oxide semiconductor thin film; the photo-generated carrier quenching metal oxide semiconductor thin film is used for quenching photo-generated carriers; the carrier mobility of the high-mobility metal oxide semiconductor thin film is greater than the carrier mobility of the photo-generated carrier quenching metal oxide semiconductor thin film; and the ratio of the difference between the carrier concentration of the photo-generated carrier quenching metal oxide semiconductor thin film under light and in a dark state to the carrier concentration under light is less than the ratio of the difference between the carrier concentration of the high-mobility metal oxide semiconductor thin film under light and in a dark state to the carrier concentration under light. The above scheme improves the carrier mobility and light stability of the metal oxide semiconductor thin film.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a metal oxide semiconductor thin film and a thin film transistor. Background Technology

[0002] Thin-film transistors (TFTs) are key components in liquid crystal displays (LCDs) and organic displays (OLEDs), playing a crucial role in the performance of these devices. Common TFT types include amorphous silicon TFTs, polycrystalline silicon TFTs, organic thin-film transistors (OLEDs), and metal-oxide-semiconductor (MOS) TFTs. Currently, MOS TFTs have attracted widespread attention and are widely used in medium-to-large-sized displays due to their ease of large-area fabrication, high mobility, good stability, and low cost. The MOS currently used for mass production while ensuring device stability is indium gallium zinc oxide (IGZO (In:Ga:Zn = 1:1:1)). This material has a relatively low mobility of only 10 cm⁻¹. 2 The efficiency is approximately / Vs. However, when attempts are made to improve the mobility of oxide thin films by changing the composition, the stability of the devices, especially their photostability, fails to meet product requirements. Therefore, how to break the contradiction between high mobility and high photostability is currently a key research focus in metal-oxide-semiconductor materials and fabrication processes.

[0003] Currently, physical vapor deposition (PVD) is the most widely used deposition method for oxide thin films. However, PVD-prepared films have relatively low density and more defects. To achieve higher mobility, a higher In / Sn ion content is required, which negatively impacts stability, especially photostability. On the other hand, considering that the mobility of oxide semiconductor thin films is determined by the overlap of In / Sn / Ga ns electron orbitals, increasing the density of metal oxide thin films and reducing the spacing between metal ions can effectively improve the mobility of the thin film material. Therefore, researchers have turned their attention to atomic layer deposition (ALD) methods for thin film preparation. ALD is a vapor-phase thin film growth method that uses the principle of saturated adsorption of precursors or reactants on the substrate surface, followed by layer-by-layer reaction and single-atom-layer growth. This growth method allows for the production of highly dense and conformally accurate oxide thin films. Simultaneously, it allows for precise control of the film thickness. Currently, metal oxide semiconductor thin films grown using this method are used to fabricate thin-film transistor (TFT) devices with mobility ranging from 30 to 120 cm⁻¹. 2Within the range of / Vs. However, the stability, especially the photostability, of TFT devices with active layers fabricated using ALD is not improved. Introducing rare earth ions into metal oxide semiconductor thin films as photostability stabilizers mainly utilizes the valence change capability of rare earth ions and suitable energy level matching to achieve rapid recombination of photogenerated carriers, thereby reducing the impact of light on TFT device performance. However, because ALD growth films depend on precursor materials, the types of oxide semiconductor materials that can be fabricated are limited, especially since rare earth organometallic sources are still immature and cannot utilize the photostability effect of rare earth ions. Therefore, it is difficult to improve the stability of active layer TFT devices fabricated using ALD under light illumination. In summary, achieving high carrier mobility and high photostability in a single metal oxide semiconductor film layer using existing technologies is very difficult. Summary of the Invention

[0004] This invention provides a metal oxide semiconductor thin film and a thin film transistor to improve the carrier mobility and photostability of the metal oxide semiconductor thin film.

[0005] According to a first aspect of the present invention, a metal oxide semiconductor thin film is provided, comprising:

[0006] At least one high-mobility metal-oxide-semiconductor thin film;

[0007] At least one photogenerated carrier quenching metal oxide semiconductor film, wherein the photogenerated carrier quenching metal oxide semiconductor film and the high-mobility metal oxide semiconductor film constitute a stacked structure; the photogenerated carrier quenching metal oxide semiconductor film is used to quench photogenerated carriers.

[0008] The carrier mobility of the high-mobility metal oxide semiconductor film is greater than that of the photogenerated carrier quenching metal oxide semiconductor film.

[0009] The ratio of the difference in carrier concentration between the photogenerated carrier quenching metal oxide semiconductor thin film under illumination and dark conditions to the carrier concentration under illumination is less than that of the high-mobility metal oxide semiconductor thin film.

[0010] According to a second aspect of the present invention, a thin-film transistor is provided, comprising any of the metal oxide semiconductor thin films described in the first aspect of the present invention.

[0011] The metal oxide semiconductor thin film provided in this invention includes a stacked structure consisting of at least one layer of photogenerated carrier quenching metal oxide semiconductor thin film and at least one layer of high-mobility metal oxide semiconductor thin film. The photogenerated carrier quenching metal oxide semiconductor thin film and the high-mobility metal oxide semiconductor thin film can each be processed using suitable processes to achieve the high carrier mobility of the high-mobility metal oxide semiconductor thin film and the high photostability of the photogenerated carrier quenching metal oxide semiconductor thin film, thereby reducing the difficulty of preparing the metal oxide semiconductor thin film.

[0012] Since the carrier mobility of high-mobility metal oxide semiconductor films is greater than that of photogenerated carrier quenching metal oxide semiconductor films, the setting of high-mobility metal oxide semiconductor films results in high carrier mobility for metal oxide semiconductor films.

[0013] Photogenerated carrier quenching metal oxide semiconductor thin films are used to quench photogenerated carriers diffused from high-mobility metal oxide semiconductor thin films. The ratio of the difference in carrier concentration between the photogenerated carrier quenching metal oxide semiconductor thin film under illumination and dark conditions to the carrier concentration under illumination is less than that of the high-mobility metal oxide semiconductor thin film under illumination and dark conditions. The setting of the photogenerated carrier quenching metal oxide semiconductor thin film gives the metal oxide semiconductor thin film high photostability.

[0014] Therefore, the metal oxide semiconductor thin film provided in this embodiment of the invention has both high carrier mobility and high photostability by forming a stacked structure consisting of at least one layer of photogenerated carrier quenching metal oxide semiconductor thin film and at least one layer of high mobility metal oxide semiconductor thin film.

[0015] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a thin-film transistor provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the Fermi level of a high-mobility metal-oxide-semiconductor thin film and a photogenerated carrier-quenched metal-oxide-semiconductor thin film.

[0019] Figure 3 yes Figure 1 A schematic diagram of the transfer characteristic curves of a thin-film transistor at nine different locations;

[0020] Figure 4 yes Figure 1 A schematic diagram of the transfer characteristic curves of a thin-film transistor under illumination and dark conditions;

[0021] Figure 5 This is a schematic diagram of another thin-film transistor structure provided in an embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of another thin-film transistor structure provided in an embodiment of the present invention;

[0023] Figure 7 yes Figure 6 A schematic diagram of the transfer characteristics of a thin-film transistor under light and dark conditions;

[0024] Figure 8 yes Figure 6 A schematic diagram of another transfer characteristic curve of a thin-film transistor under illumination and dark conditions;

[0025] Figure 9 This is a schematic diagram of another thin-film transistor structure provided in an embodiment of the present invention;

[0026] Figure 10 This is a schematic diagram of another thin-film transistor structure provided in an embodiment of the present invention;

[0027] Figure 11 This is a flowchart of a method for fabricating a thin-film transistor according to an embodiment of the present invention;

[0028] Figures 12-15 yes Figure 11 A structural diagram corresponding to each step in the process;

[0029] Figure 16 This is a flowchart of a method for fabricating a thin-film transistor according to an embodiment of the present invention;

[0030] Figures 17-21 yes Figure 16 A structural diagram corresponding to each step in the process;

[0031] Figure 22 This is a flowchart of a method for fabricating a thin-film transistor according to an embodiment of the present invention;

[0032] Figures 23-27 yes Figure 22 A structural diagram corresponding to each step in the process;

[0033] Figure 28 This is a schematic diagram of the photoresponse characteristics of a thin-film transistor with a single-layer high-mobility oxide thin film as the active layer material, provided by an embodiment of the present invention.

[0034] Figure 29 This is a schematic diagram of the photoresponse characteristics of a thin-film transistor with a single-layer photogenerated carrier quenching metal oxide semiconductor thin film as the active layer, provided by an embodiment of the present invention. Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that includes a series of steps or apparatuses is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatuses.

[0037] To address the aforementioned technical problems, embodiments of the present invention provide the following technical solutions:

[0038] like Figure 1 As shown, Figure 1This is a schematic diagram of a thin-film transistor (TFT) according to an embodiment of the present invention. The TFT includes a metal-oxide-semiconductor (MODS) thin film 100, which includes at least one high-mobility MODS thin film 101 and at least one photogenerated carrier quenching MODS thin film 102. The photogenerated carrier quenching MODS thin film 102 and the high-mobility MODS thin film 101 form a stacked structure. The photogenerated carrier quenching MODS thin film 102 is used to quench photogenerated carriers. The carrier mobility of the high-mobility MODS thin film 101 is greater than that of the photogenerated carrier quenching MODS thin film 102. The ratio of the difference in carrier concentration between the photogenerated carrier quenching MODS thin film 102 under illumination and dark conditions to the carrier concentration under illumination is less than that of the high-mobility MODS thin film 101 under illumination and dark conditions to the carrier concentration under illumination.

[0039] The difference A0 between the ratio of carrier concentration under illumination and dark conditions to the carrier concentration under illumination satisfies the following relationship:

[0040] A0=((n photo -n dark ) / n photo )

[0041] Where, n photo Let n be the carrier concentration under illumination, representing the carrier mobility. dark denoted as carrier concentration in the dark state, representing carrier mobility.

[0042] The metal oxide semiconductor thin film 100 provided in this embodiment of the invention includes a stacked structure composed of at least one layer of photogenerated carrier quenching metal oxide semiconductor thin film 102 and at least one layer of high-mobility metal oxide semiconductor thin film 101. The photogenerated carrier quenching metal oxide semiconductor thin film 102 and the high-mobility metal oxide semiconductor thin film 101 can each be selected with suitable processes to achieve the high carrier mobility of the high-mobility metal oxide semiconductor thin film 101 and the high photostability of the photogenerated carrier quenching metal oxide semiconductor thin film 102, thereby reducing the fabrication difficulty of the metal oxide semiconductor thin film 100.

[0043] Since the carrier mobility of the high-mobility metal oxide semiconductor thin film 101 is greater than that of the photogenerated carrier quenching metal oxide semiconductor thin film 102, the high-mobility metal oxide semiconductor thin film 101 enables the metal oxide semiconductor thin film 100 to have a high carrier mobility.

[0044] The photogenerated carrier quenching metal-oxide-semiconductor thin film 102 is used to quench photogenerated carriers diffused from the high-mobility metal-oxide-semiconductor thin film 101, and the ratio of the difference in carrier concentration between the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 under illumination and dark conditions to the carrier concentration under illumination is ((n... photo -n dark ) / n photo The ratio of the difference in carrier concentration between the high-mobility metal-oxide-semiconductor thin film 101 under illumination and dark conditions to the carrier concentration under illumination is less than (n). photo -n dark ) / n photo The arrangement of the photogenerated carrier quenching metal oxide semiconductor thin film 102 enables the metal oxide semiconductor thin film 100 to have high photostability.

[0045] Therefore, the metal oxide semiconductor thin film 100 provided in this embodiment of the invention has both high carrier mobility and high photostability by forming a stacked structure consisting of at least one layer of photogenerated carrier quenching metal oxide semiconductor thin film 102 and at least one layer of high mobility metal oxide semiconductor thin film 101.

[0046] It should be noted that the metal oxide semiconductor thin film 100 provided in this embodiment of the invention is used as the active layer of a thin film transistor. Therefore, the stacked structure of the metal oxide semiconductor thin film 100 is illustrated using the structure of a thin film transistor as an example. Since the metal oxide semiconductor thin film 100 has both high carrier mobility and high photostability, when used as the active layer of a thin film transistor, it improves both the carrier mobility and photostability of the thin film transistor. Figure 28 This is a schematic diagram of the photoresponse characteristics of a thin-film transistor with a single-layer high-mobility oxide thin film as the active layer material.

[0047] Figure 29 This is a schematic diagram illustrating the photoresponse characteristics of a thin-film transistor with a single-layer photogenerated carrier-quenched metal-oxide-semiconductor thin film as the active layer material. Figure 28 and Figure 29 As can be seen, the photogenerated carrier quenching metal oxide semiconductor thin film 102 can effectively reduce the impact of photogenerated carriers on the characteristics of TFT devices. Here, "in dark" represents the dark state, and 3k nits, 15k nits, 55k nits, and 140k nits represent different light intensities.

[0048] Optionally, based on the above technical solutions, such as Figure 2 As shown, Figure 2This is a schematic diagram of the Fermi levels of a high-mobility metal-oxide-semiconductor (MOS) thin film and a photogenerated carrier-quenched MOS thin film. The absolute value of the difference between the Fermi level of the photogenerated carrier-quenched MOS thin film 102 and the Fermi level of the high-mobility MOS thin film 101 relative to the vacuum Fermi level is less than or equal to 0.5 eV. The expression for the absolute value of the difference between the Fermi level of the photogenerated carrier-quenched MOS thin film 102 and the Fermi level of the high-mobility MOS thin film 101 relative to the vacuum Fermi level is as follows:

[0049] |ΔE|=|(E CBMB -E VAC )-(E CBMA -E VAC )|

[0050] Where |ΔE| is the absolute value of the difference between the Fermi level of the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 and the Fermi level of the high-mobility metal-oxide-semiconductor thin film 101 relative to the vacuum Fermi level; E CBMB The Fermi level of the photogenerated carrier quenching metal-oxide-semiconductor thin film 102; E CBMA The Fermi level of the high-mobility metal-oxide-semiconductor thin film 101; E VAC It is the vacuum Fermi level.

[0051] Specifically, the absolute value of the difference between the Fermi level of the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 and the Fermi level of the high-mobility metal-oxide-semiconductor thin film 101 relative to the vacuum Fermi level is less than or equal to 0.5 eV. This ensures that photogenerated carriers generated in the high-mobility metal-oxide-semiconductor thin film 101 can be injected into the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 using physical effects such as potential energy difference, thermal energy, and concentration difference. This, in turn, allows the IV characteristic to remain stable even under strong light irradiation.

[0052] Optionally, based on the above technical solution, the thickness of the high-mobility metal oxide semiconductor thin film 101 is greater than or equal to 10 angstroms and less than or equal to 500 angstroms; and / or, the thickness of the photogenerated carrier quenching metal oxide semiconductor thin film 102 is greater than or equal to 100 angstroms and less than or equal to 2000 angstroms.

[0053] Specifically, the thickness of the high-mobility metal-oxide-semiconductor thin film 101 is in the range of 10 angstroms to 500 angstroms, making the thickness of the high-mobility metal-oxide-semiconductor thin film 101 less than or equal to the diffusion length of photogenerated carriers. This allows photogenerated carriers within the high-mobility metal-oxide-semiconductor thin film 101 to diffuse to the photogenerated carrier quenching metal-oxide-semiconductor thin film 102, thereby quenching excitons. Specifically, rare earth ions in the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 have high binding energies with oxygen, meaning that the binding of rare earth ions with oxygen atoms is relatively stable. Therefore, they are often used as inhibitors of oxygen vacancies. Since oxygen vacancies are considered a source of conductivity in metal-oxide-semiconductor materials, the doping of rare earth ions typically leads to a decrease in carrier concentration, achieving exciton quenching.

[0054] The thickness of the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 is greater than or equal to 100 angstroms and less than or equal to 2000 angstroms. If the thickness of the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 is too thick, exceeding 2000 angstroms, it will result in insufficient gate control capability of the thin-film transistor. If the thickness of the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 is too thin, less than 100 angstroms, it will result in insufficient photostability of the metal-oxide-semiconductor thin film 100.

[0055] Optionally, based on the above technical solution, at least one surface of the high-mobility metal oxide semiconductor thin film 101 is provided with a photogenerated carrier quenching metal oxide semiconductor thin film 102, so that the photogenerated carrier quenching metal oxide semiconductor thin film 102 is used to quench photogenerated carriers diffused from the high-mobility metal oxide semiconductor thin film 101, thereby improving the photostability of the metal oxide semiconductor thin film 100.

[0056] Optionally, based on the above technical solution, the stacked structure composed of the high-mobility metal oxide semiconductor thin film 101 and the photogenerated carrier quenching metal oxide semiconductor thin film 102 includes any one of the following: AB stacked structure, BAB stacked structure, ABAB stacked structure, and ABBAB stacked structure; wherein, A is the high-mobility metal oxide semiconductor thin film 101, and B is the photogenerated carrier quenching metal oxide semiconductor thin film 102.

[0057] Table 1 shows the fabrication parameters and performance of a metal-oxide-semiconductor thin film in a thin-film transistor with an AB stacked structure.

[0058]

[0059] Table 2 shows the fabrication parameters and performance of metal-oxide-semiconductor thin films in another type of thin-film transistor with an AB stacked structure.

[0060]

[0061]

[0062] Table 3 shows the fabrication parameters and performance of metal-oxide-semiconductor thin films in another type of thin-film transistor with an AB stacked structure.

[0063]

[0064] Tables 1 and 2 show that the thin-film transistor (TFT) with an AB stacked structure exhibits high carrier mobility and high photostability. The absolute values ​​of the Fermi level difference for both types of films are less than 0.5 eV. In the tables, ΔVth for top-light incidence represents the change in threshold voltage (ΔVth) of the TFT when light is incident from the side of the passivation layer 205 away from the substrate 200, and in the dark state. ΔVth for bottom-light incidence represents the change in threshold voltage (ΔVth) of the TFT when light is incident from the side of the substrate 200 away from the passivation layer 205, and in the dark state. In Tables 1 and 2, the absolute value of ΔVth is less than 2 V regardless of whether the light is incident from the top or bottom. The overall photostability of this structure is excellent. However, in Table 3, the Fermi level difference for different active layer films is greater than 0.5 eV. Therefore, the final device exhibits a larger photoresponse characteristic, indicating that the transfer of photogenerated carriers in the AB stacked structure is suppressed. Figure 1 In the schematic diagram of the thin-film transistor shown, the stacked structure composed of the high-mobility metal-oxide-semiconductor thin film 101 and the photogenerated carrier-quenching metal-oxide-semiconductor thin film 102 is an AB stacked structure. Figure 1 As shown, the thin-film transistor includes: a substrate 200; a gate 201 located on one side of the substrate 200; a gate insulating layer 202 located on the side of the gate 201 away from the substrate 200; a metal oxide semiconductor thin film 100 located on the side of the gate insulating layer 202 away from the gate 201; a source 203 located on the side of the gate insulating layer 202 away from the gate 201 and covering a portion of the metal oxide semiconductor thin film 100; a drain 204 located on the side of the gate insulating layer 202 away from the gate 201 and covering a portion of the metal oxide semiconductor thin film 100; and a passivation layer 205 located on the side of the metal oxide semiconductor thin film 100 away from the gate insulating layer 202 and covering the source 203 and the drain 204.

[0065] like Figure 3 As shown, Figure 3 yes Figure 1A schematic diagram of the transfer characteristic curves of a thin-film transistor at nine different locations, from... Figure 3 The data shows that the device mobility of this thin-film transistor is 66.4 cm⁻¹. 2 / Vs, subthreshold swing SS is 0.26V / Dec, and threshold voltage is -0.68V. And Figure 3 The transfer characteristic curves of the thin-film transistor at nine different locations are shown. The high degree of overlap among the transfer characteristic curves at these nine locations demonstrates the high uniformity of the thin-film transistor at various locations. Figure 4 As shown, Figure 4 yes Figure 1 The schematic diagram shows the transfer characteristic curves of the thin-film transistor under light and dark conditions. In this thin-film transistor, when 6000 nits of light is incident from the side of the passivation layer 205 away from the substrate 200 and in the dark condition, the change threshold voltage (ΔVth) of the thin-film transistor is less than 1.0V, which shows high photostability.

[0066] in, Figure 3 and Figure 4 The schematic diagram of the transfer characteristic curve corresponds to the following method for fabricating a thin-film transistor: SiN is prepared on a 20µm flexible polyimide (PI) film. x SiO2 laminated thin film as a buffer layer Figure 1 (Buffer layer not shown). SiN x The thickness of the buffer layer is 350 nm, and the thickness of the SiO2 layer is 150 nm. Then, a Mo and Cu stacked electrode is fabricated on top of the buffer layer as the gate electrode 201, with the Mo metal layer having a thickness of 30 nm and the Cu metal layer having a thickness of 600 nm; then, SiN is deposited. x The stack of SiO2 and SiN serves as the gate insulating layer 202. x The thickness of the first layer is 250 nm, and the thickness of the second layer is 100 nm. Subsequently, an AB stack structure consisting of a high-mobility metal oxide semiconductor film 101 and a photogenerated carrier quenching metal oxide semiconductor film 102 is sequentially deposited. The high-mobility metal oxide semiconductor film 101 has a thickness of 5 nm, and the photogenerated carrier quenching metal oxide semiconductor film 102 has a thickness of 30 nm. The high-mobility metal oxide semiconductor film 101 is fabricated using an ALD (Alternating Discharge) device.

[0067] like Figure 5 In the schematic diagram of the thin-film transistor shown, Figure 5 This is a schematic diagram of another thin-film transistor structure provided in an embodiment of the present invention. The stacked structure composed of the high-mobility metal oxide semiconductor thin film 101 and the photogenerated carrier quenching metal oxide semiconductor thin film 102 is an ABBAB stacked structure. Figure 5 The thin-film transistor shown and Figure 1The difference in the thin-film transistor shown is that the stacked structure composed of the high-mobility metal-oxide-semiconductor thin film 101 and the photogenerated carrier-quenching metal-oxide-semiconductor thin film 102 is an ABBAB stacked structure. Furthermore, the increase in the number of layers of the photogenerated carrier-quenching metal-oxide-semiconductor thin film 102 further improves the photostability of the thin-film transistor; the increase in the number of layers of the high-mobility metal-oxide-semiconductor thin film 101 further improves the carrier mobility of the thin-film transistor.

[0068] like Figure 6 In the schematic diagram of the thin-film transistor shown, Figure 6 This is a schematic diagram of another thin-film transistor structure provided in an embodiment of the present invention. The stacked structure composed of the high-mobility metal-oxide-semiconductor thin film 101 and the photogenerated carrier-quenching metal-oxide-semiconductor thin film 102 is a BAB stacked structure. Figure 6 As shown, the thin-film transistor includes a substrate 200; a buffer layer 300 located on one side of the substrate 200; a metal-oxide-semiconductor thin film 100 located on the side of the buffer layer 300 away from the substrate 200; a gate insulating layer 202 located on the side of the metal-oxide-semiconductor thin film 100 away from the buffer layer 300; a gate 201 located on the side of the gate insulating layer 202 away from the metal-oxide-semiconductor thin film 100; and an interlayer insulating layer 400 located on the side of the gate 201 away from the metal-oxide-semiconductor thin film 100. The interlayer insulating layer 400 also covers the side surfaces of the gate 201 and the gate insulating layer 202, and the interlayer insulating layer 400 is provided with a first via T1 and a second via T2. Through-hole T2, the first through-hole T1 exposes a portion of the surface of the metal oxide semiconductor thin film 100, and the second through-hole T2 exposes a portion of the surface of the metal oxide semiconductor thin film 100; Source 203, located on the side of the interlayer insulating layer 400 away from the substrate 200, reaches the metal oxide semiconductor thin film 100 through the first through-hole T1 and is electrically connected to the metal oxide semiconductor thin film 100; Drain 204, located on the side of the interlayer insulating layer 400 away from the substrate 200, reaches the metal oxide semiconductor thin film 100 through the second through-hole T2 and is electrically connected to the metal oxide semiconductor thin film 100; Passivation layer 205, located on the side of the source 203 and drain 204 away from the substrate 200, and covers the interlayer insulating layer 400. It should be noted that in other optional embodiments, it is also possible to... Figure 5 and Figure 6 The thin-film transistor shown has a higher mobility metal oxide semiconductor thin film 101 and a photogenerated carrier quenching metal oxide semiconductor thin film 102 with more layers.

[0069] Figure 7 yes Figure 6 A schematic diagram of the transfer characteristics of a thin-film transistor under illumination and dark conditions. Figure 8 yes Figure 6 A schematic diagram illustrating another transfer characteristic curve of a thin-film transistor under illumination and dark conditions. Among them, Figure 7 In the middle, light enters from one side of the substrate 200. Figure 8 In the middle, light is incident from one side of the passivation layer 205.

[0070] like Figure 7 and Figure 8 As shown, the device mobility in this thin-film transistor is 82.4 cm⁻¹. 2 The subthreshold swing SS is 0.31V / Dec, and the threshold voltage is -0.91V. When 6000 nits of light is incident from the side of the passivation layer 205 away from the substrate 200, and in the dark state, the change in threshold voltage (ΔVth) of this thin-film transistor is less than 2.0V, exhibiting high photostability. When 6000 nits of light is incident from the side of the substrate 200 away from the passivation layer 205, and in the dark state, the change in threshold voltage (ΔVth) of this thin-film transistor is less than 0.5V, also exhibiting high photostability.

[0071] in, Figure 7 and Figure 8 The fabrication method of the thin-film transistor corresponding to the schematic diagram of the transfer characteristic curve is as follows: A SiO2 thin film is prepared as a buffer layer 300 on a 0.5 mm thick glass substrate 200. The SiO2 thickness is 400 nm. Then, a BAB stack structure of a photogenerated carrier quenching metal oxide semiconductor film 102, a high-mobility metal oxide semiconductor film 101, and a photogenerated carrier quenching metal oxide semiconductor film 102 is sequentially formed on the buffer layer 300. The high-mobility metal oxide semiconductor film 101 has a thickness of 20 nm, the photogenerated carrier quenching metal oxide semiconductor film 102 near the substrate 200 has a thickness of 10 nm, and the photogenerated carrier quenching metal oxide semiconductor film 102 near the passivation layer 205 has a thickness of 80 nm. The high-mobility metal oxide semiconductor film 101 is prepared using an ALD device.

[0072] like Figure 9 In the schematic diagram of the thin-film transistor shown, Figure 9 This is a schematic diagram of another thin-film transistor structure provided in this embodiment of the invention. The stacked structure composed of the high-mobility metal-oxide-semiconductor thin film 101 and the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 is an ABAB stacked structure. The photogenerated carrier quenching metal-oxide-semiconductor thin film 102 near the substrate 200 is In... 0.200 Zn 0.500 Ga0.250 Dy 0.050 O was deposited using PVD sputtering equipment. The sputtering pressure of the PVD sputtering process was 0.3 mTorr, and the Ar / O ratio was 40%. The photogenerated carrier quenching metal-oxide-semiconductor thin film 102 near the passivation layer 205 was Zn. 0.500 Ga 0442 Ti 0.008 Dy 0.050 The active layer (O) was deposited using PVD sputtering equipment. The sputtering pressure of the PVD sputtering process was 0.7 mTorr, and the Ar / O ratio was 60%. Then, oxalic acid was used to etch and pattern the active layer at room temperature, forming island-shaped active layers. SiO2 was then deposited as the gate insulating layer 202 with a thickness of 150 nm; subsequently, Mo metal was deposited as the gate 201 with a thickness of 200 nm; then, a 300 nm thick SiO2 layer was deposited and patterned using dry etching as the interlayer insulating layer 400; then, TiAlTi stacked electrodes were fabricated on the interlayer insulating layer 400 and patterned using dry etching as the source 203 and drain 204. The thickness of the Ti metal layers on both sides of the Al metal layer was 30 nm, and the thickness of the Al metal layer was 500 nm. Then, a stacked insulating film of SiO2 and SiNx was deposited as the passivation layer 205, with a SiO2 thickness of 300 nm and a SiNx thickness of 100 nm. Finally, the device was annealed at 350 °C for 1 hour to complete the TFT device fabrication.

[0073] Optionally, based on the above technical solutions, such as Figure 1 As shown, the chemical formula of the high-mobility metal oxide semiconductor thin film 101 is (MO). x (NO) y Wherein, 0.4≤x≤1, 0≤y≤0.6, x+y=1; M includes one element or any combination of at least two elements from In, Sn, and Ga; N includes one element or any combination of at least two elements from Zn, Ga, Si, Al, Mo, W, Sc, Y, Hf, Zr, Ta, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Yb, Sb, and Bi.

[0074] Specifically, the conduction band bottom of metal oxides, represented by Ga2O3, SnO2, and In2O3, is mainly composed of the ns electron orbitals of metal ions. The spherical ns electron orbitals allow for a high degree of electron orbital overlap even in an amorphous disordered state, ensuring a sufficient number of charge carriers. Therefore, when M includes one or more of In, Sn, and Ga, or any combination of at least two elements, a suitable process can be selected to achieve a relatively high carrier mobility in the high-mobility metal oxide semiconductor thin film 101. Oxides formed from Zn, Ga, Si, Al, Mo, W, Sc, Y, Hf, Zr, Ta, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Yb, Sb, and Bi can increase the stability of the high-mobility metal oxide semiconductor thin film 101, giving it a certain degree of electrical and optical stability.

[0075] Optionally, based on the above technical solutions, such as Figure 1 As shown, the chemical formula of the photogenerated carrier quenching metal oxide semiconductor thin film 102 is (M'O). x’ (N'O) y’ Where 0.950≤x'≤0.9998, 0.0002≤y'≤0.050, x'+y'=1; M' includes one element or any combination of at least two elements from In, Zn, Ga, Sn, Zr, Ta, Ti, and Hf; N' includes one element or any combination of at least two elements from Ce, Pr, Tb, Dy, and Yb.

[0076] Rare earth ions have high binding energies with oxygen, meaning that the combination of rare earth ions and oxygen atoms is relatively stable. Therefore, they are often used as inhibitors of oxygen vacancies. Since oxygen vacancies are considered a source of conductivity in metal oxide semiconductors, doping with rare earth ions usually leads to a decrease in carrier concentration.

[0077] Specifically, Ce, Pr, Tb, Dy, and Yb belong to rare earth elements. The oxides formed by Ce, Pr, Tb, Dy, and Yb utilize the valence change capability of rare earth ions and suitable energy level matching to achieve rapid recombination of photogenerated carriers. This, in turn, enables the photogenerated carrier quenching metal oxide semiconductor thin film 102 to quench photogenerated carriers, thereby exhibiting high photostability and reducing the impact of light on the performance of thin-film transistor devices. The oxides formed by In, Zn, Ga, Sn, Zr, Ta, Ti, and Hf elements can enable the photogenerated carrier quenching metal oxide semiconductor thin film 102 to possess a certain carrier mobility.

[0078] Optionally, the photogenerated carrier quenching metal-oxide-semiconductor thin film 102 may preferably, but is not limited to, the following proportions: In 0.332 Ga0.332 Zn 0.332 Yb 0.005 O、In 0.476 Ga 0.238 Sn 0.238 Tb 0.0476 O、In 0.485 Ga 0.485 Ti 0.005 Dy 0.0243 O、In 0.485 Ga 0.485 Ti 0.005 Dy 0.0243 O.Ga 0.737 Zn 0.246 Hf 0.002 Pr 0.0147 O.

[0079] Optionally, based on the above technical solutions, such as Figure 1 As shown, the high-mobility metal oxide semiconductor thin film 101 can be prepared by any one of atomic layer deposition, physical vapor deposition and pulsed laser deposition.

[0080] Specifically, by using any one of atomic layer deposition, physical vapor deposition, and pulsed laser deposition to prepare a high-mobility metal oxide semiconductor thin film 101, a highly dense and conformal oxide thin film can be obtained. Simultaneously, the film thickness can be precisely controlled, enabling the high-mobility metal oxide semiconductor thin film 101 to possess high carrier mobility.

[0081] Optionally, based on the above technical solutions, such as Figure 1 As shown, the preparation method of the photogenerated carrier quenching metal oxide semiconductor thin film 102 includes at least one of physical vapor deposition, solution deposition, and pulsed laser deposition.

[0082] Specifically, the photogenerated carrier quenching metal oxide semiconductor thin film 102 is prepared using at least one of physical vapor deposition, solution deposition, and pulsed laser deposition. This allows for the preparation of a wide variety of oxide semiconductors, particularly rare earth metal oxide semiconductors, which are well-established and can effectively utilize the photostability of rare earth ions, resulting in high photostability of the photogenerated carrier quenching metal oxide semiconductor thin film 102. Optionally, based on the above technical solution, the carrier mobility of the high-mobility metal oxide semiconductor thin film 101 is greater than or equal to 30 cm⁻¹. 2 / Vs.

[0083] Specifically, the carrier mobility of the high-mobility metal-oxide-semiconductor thin film 101 is greater than or equal to 30 cm⁻¹. 2 / Vs enables thin-film transistors to have high carrier mobility.

[0084] Optionally, based on the above technical solution, the carrier concentration of the high-mobility metal oxide semiconductor thin film 101 is on the order of 10. 17 ~10 20 The carrier concentration of the photogenerated carrier quenching metal oxide semiconductor thin film 102 is on the order of 10c / cmc; and / or, the carrier concentration of the photogenerated carrier quenching metal oxide semiconductor thin film 102 is on the order of 10c / cmc. 16 ~10 19 Units per cubic meter.

[0085] Specifically, the carrier concentration of the high-mobility metal-oxide-semiconductor thin film 101 is on the order of 10. 17 ~10 20 Preferably, the carrier concentration of the high-mobility metal oxide semiconductor thin film 101 is on the order of magnitude greater than the carrier concentration of the photogenerated carrier quenching metal oxide semiconductor thin film 102, so that the high-mobility metal oxide semiconductor thin film 101 has a high carrier mobility.

[0086] This invention also provides a thin-film transistor. The active layer of this thin-film transistor is any of the metal-oxide-semiconductor thin films 100 described in this invention. Therefore, this thin-film transistor possesses both high carrier mobility and high photostability. Optionally, based on the above technical solution, such as... Figure 1 As shown, the thin-film transistor includes: a substrate 200; a gate 201 located on one side of the substrate 200; a gate insulating layer 202 located on the side of the gate 201 away from the substrate 200; a metal oxide semiconductor thin film 100 located on the side of the gate insulating layer 202 away from the gate 201; a source 203 located on the side of the gate insulating layer 202 away from the gate 201 and covering a portion of the metal oxide semiconductor thin film 100; a drain 204 located on the side of the gate insulating layer 202 away from the gate 201 and covering a portion of the metal oxide semiconductor thin film 100; and a passivation layer 205 located on the side of the metal oxide semiconductor thin film 100 away from the gate insulating layer 202 and covering the source 203 and the drain 204.

[0087] For example, the stacked structure composed of a high-mobility metal oxide semiconductor thin film 101 and a photogenerated carrier quenching metal oxide semiconductor thin film 102 includes an AB stacked structure.

[0088] Optionally, based on the above technical solutions, such as Figure 6As shown, the thin-film transistor includes a substrate 200; a buffer layer 300 located on one side of the substrate 200; a metal-oxide-semiconductor thin film 100 located on the side of the buffer layer 300 away from the substrate 200; a gate insulating layer 202 located on the side of the metal-oxide-semiconductor thin film 100 away from the buffer layer 300; a gate 201 located on the side of the gate insulating layer 202 away from the metal-oxide-semiconductor thin film 100; and an interlayer insulating layer 400 located on the side of the gate 201 away from the metal-oxide-semiconductor thin film 100. The interlayer insulating layer 400 also covers the side surfaces of the gate 201 and the gate insulating layer 202, and the interlayer insulating layer 400 is provided with a first via T1 and a second via T2. Hole T2, the first via T1 exposes a portion of the surface of the metal oxide semiconductor thin film 100, and the second via T2 exposes a portion of the surface of the metal oxide semiconductor thin film 100; Source 203, the source 203 is located on the side of the interlayer insulating layer 400 away from the substrate 200, the source 203 reaches the metal oxide semiconductor thin film 100 through the first via T1, and is electrically connected to the metal oxide semiconductor thin film 100; Drain 204, the drain 204 is located on the side of the interlayer insulating layer 400 away from the substrate 200, the interlayer insulating layer 400 reaches the metal oxide semiconductor thin film 100 through the second via T2, and is electrically connected to the metal oxide semiconductor thin film 100; Passivation layer 205, the passivation layer 205 is located on the side of the source 203 and drain 204 away from the substrate 200, and covers the interlayer insulating layer 400.

[0089] For example, the stacked structure composed of the high-mobility metal oxide semiconductor thin film 101 and the photogenerated carrier quenching metal oxide semiconductor thin film 102 is a BAB stacked structure.

[0090] It should be noted that in other optional embodiments, it is also possible to... Figure 6 The thin-film transistor shown has a higher mobility metal oxide semiconductor thin film 101 and a photogenerated carrier quenching metal oxide semiconductor thin film 102 with more layers.

[0091] Optionally, based on the above technical solutions, such as Figure 10 As shown, Figure 10 This is a schematic diagram of another thin-film transistor provided in an embodiment of the present invention. The thin-film transistor also includes a light-shielding layer 500, which is located between the substrate 200 and the buffer layer 300.

[0092] Optionally, the light-shielding layer 500 can be a conductive metal layer. The light-shielding layer 500 is located between the substrate 200 and the buffer layer 300, which increases the photostability of the bottom side of the thin-film transistor when it is photosensitive.

[0093] This invention also provides a method for fabricating a thin-film transistor, specifically... Figure 1 The thin-film transistor shown, such as Figure 11 As shown, Figure 11 This is a flowchart of a method for fabricating a thin-film transistor according to an embodiment of the present invention. The method for fabricating the thin-film transistor is as follows:

[0094] S110. A metal conductive layer is fabricated and patterned on the substrate as a gate.

[0095] like Figure 12 As shown, a metal conductive layer is fabricated and patterned on substrate 200 as gate 201.

[0096] S120. A first insulating film is deposited on the metal conductive layer as a gate insulating layer.

[0097] like Figure 13 As shown, a first insulating film is deposited on the metal conductive layer as the gate insulating layer 202.

[0098] S130. A metal oxide semiconductor thin film is formed on the gate insulating layer and patterned as an active layer.

[0099] like Figure 14 As shown, a stacked structure consisting of at least one high-mobility metal-oxide-semiconductor thin film 101 and at least one photogenerated carrier quenching metal-oxide-semiconductor thin film 102 deposited on the gate insulating layer 202 is described. This stacked structure is a metal-oxide-semiconductor thin film 100, which, after patterning, serves as the active layer. Exemplarily, this stacked structure includes an AB stacked structure, where A is the high-mobility metal-oxide-semiconductor thin film 101 and B is the photogenerated carrier quenching metal-oxide-semiconductor thin film 102.

[0100] Optionally, the high-mobility metal oxide semiconductor thin film 101 can be prepared by any one of atomic layer deposition, physical vapor deposition, and pulsed laser deposition. The photogenerated carrier quenching metal oxide semiconductor thin film 102 can be prepared by at least one of physical vapor deposition, solution deposition, and pulsed laser deposition.

[0101] S140. Deposit a metal layer on the active layer and then pattern it as the source and drain.

[0102] like Figure 15 As shown, a metal layer is deposited on the active layer and then patterned as the source 203 and drain 204.

[0103] S150, deposit a second insulating film as a passivation layer on the source and drain.

[0104] like Figure 1As shown, a second insulating film is deposited on the source electrode 203 and the drain electrode 204 as a passivation layer 205.

[0105] This invention also provides another method for fabricating thin-film transistors, specifically... Figure 6 The thin-film transistor shown, such as Figure 16 As shown, Figure 16 This is a flowchart of a method for fabricating a thin-film transistor according to an embodiment of the present invention. The method for fabricating the thin-film transistor is as follows:

[0106] S210. Deposit a first insulating film as a buffer layer on the substrate.

[0107] like Figure 17 As shown, a first insulating film is deposited on the substrate 200 as a buffer layer 300.

[0108] S220. A metal oxide semiconductor thin film is formed on the buffer layer and patterned as an active layer.

[0109] like Figure 17 As shown, a stacked structure consisting of at least one high-mobility metal-oxide-semiconductor thin film 101 and at least one photogenerated carrier quenching metal-oxide-semiconductor thin film 102 deposited on a buffer layer 300 is described. The metal-oxide-semiconductor thin film 100 is patterned and used as an active layer. For example, this stacked structure includes a BAB stacked structure, where A is the high-mobility metal-oxide-semiconductor thin film 101 and B is the photogenerated carrier quenching metal-oxide-semiconductor thin film 102.

[0110] Optionally, the high-mobility metal oxide semiconductor thin film 101 can be prepared by any one of atomic layer deposition, physical vapor deposition, and pulsed laser deposition. The photogenerated carrier quenching metal oxide semiconductor thin film 102 can be prepared by at least one of physical vapor deposition, solution deposition, and pulsed laser deposition.

[0111] S230. A second insulating layer is deposited on the active layer as a gate insulating layer.

[0112] like Figure 18 As shown, a second insulating layer is deposited on the active layer as a gate insulating layer 202.

[0113] S240. A metal layer is deposited on the gate insulating layer and then patterned as the gate.

[0114] like Figure 19 As shown, a metal layer is deposited on the gate insulating layer 202 and then patterned as the gate 201.

[0115] S250. A third insulating film is deposited on the metal conductive layer and then patterned as an interlayer insulating layer.

[0116] like Figure 20 As shown, a third insulating film is deposited on a metal conductive layer and then patterned as an interlayer insulating layer 400 to form a first via T1 and a second via T2.

[0117] S260. Deposit a metal layer on the interlayer insulating layer and then pattern it as the source and drain.

[0118] like Figure 21 As shown, a metal layer is deposited on the interlayer insulating layer 400 and then patterned as the source 203 and drain 204.

[0119] S270, A fourth insulating film is deposited on the source and drain as a passivation layer.

[0120] like Figure 6 As shown, a fourth insulating film is deposited on the source 203 and drain 204 as a passivation layer 205.

[0121] This invention also provides another method for fabricating thin-film transistors, specifically... Figure 10 The thin-film transistor shown, such as Figure 22 As shown, Figure 22 This is a flowchart of a method for fabricating a thin-film transistor according to an embodiment of the present invention. The method for fabricating the thin-film transistor is as follows:

[0122] S310. Prepare and pattern a metal conductive layer on the substrate as a light-shielding layer.

[0123] like Figure 23 As shown, a metal conductive layer is fabricated and patterned on the substrate 200 as a light-shielding layer 500.

[0124] S320. A first insulating film is deposited on the light-shielding layer as a buffer layer.

[0125] like Figure 23 As shown, a first insulating film is deposited on the light-shielding layer 500 as a buffer layer 300.

[0126] S330. A metal oxide semiconductor thin film is formed on the buffer layer and patterned as an active layer.

[0127] like Figure 23 As shown, a stacked structure consisting of at least one high-mobility metal-oxide-semiconductor thin film 101 and at least one photogenerated carrier quenching metal-oxide-semiconductor thin film 102 deposited on a buffer layer 300 is described. The metal-oxide-semiconductor thin film 100 is patterned and used as an active layer. For example, this stacked structure includes a BAB stacked structure, where A is the high-mobility metal-oxide-semiconductor thin film 101 and B is the photogenerated carrier quenching metal-oxide-semiconductor thin film 102.

[0128] Optionally, the high-mobility metal oxide semiconductor thin film 101 can be prepared by any one of atomic layer deposition, physical vapor deposition, and pulsed laser deposition. The photogenerated carrier quenching metal oxide semiconductor thin film 102 can be prepared by at least one of physical vapor deposition, solution deposition, and pulsed laser deposition.

[0129] S340. A second insulating layer is deposited on the active layer as a gate insulating layer.

[0130] like Figure 24 As shown, a second insulating layer is deposited on the active layer as a gate insulating layer 202.

[0131] S350, deposit a metal layer on the gate insulating layer and then pattern it as the gate.

[0132] like Figure 25 As shown, a metal layer is deposited on the gate insulating layer 202 and then patterned as the gate 201.

[0133] S360. A third insulating film is deposited on the metal conductive layer and then patterned as an interlayer insulating layer.

[0134] like Figure 26 As shown, a third insulating film is deposited on a metal conductive layer and then patterned as an interlayer insulating layer 400 to form a first via T1 and a second via T2.

[0135] S370. A metal layer is deposited on the interlayer insulating layer and then patterned as the source and drain.

[0136] like Figure 27 As shown, a metal layer is deposited on the interlayer insulating layer 400 and then patterned as the source 203 and drain 204.

[0137] S380, a fourth insulating film is deposited on the source and drain as a passivation layer.

[0138] like Figure 10 As shown, a fourth insulating film is deposited on the source 203 and drain 204 as a passivation layer 205.

[0139] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0140] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A metal oxide semiconductor thin film, characterized in that, include: At least one high-mobility metal-oxide-semiconductor thin film; At least one photogenerated carrier quenching metal oxide semiconductor film, wherein the photogenerated carrier quenching metal oxide semiconductor film and the high-mobility metal oxide semiconductor film constitute a stacked structure; the photogenerated carrier quenching metal oxide semiconductor film is used to quench photogenerated carriers. The carrier mobility of the high-mobility metal oxide semiconductor film is greater than that of the photogenerated carrier quenching metal oxide semiconductor film. The ratio of the difference in carrier concentration between the photogenerated carrier quenching metal oxide semiconductor film under illumination and dark conditions to the carrier concentration under illumination is less than that of the high-mobility metal oxide semiconductor film. The photo-generated carrier quenching metal oxide semiconductor thin film has a chemical formula of (M'O) x’ (N'O) y’ wherein 0.950≤x'≤0.9998, 0.0002≤y'≤0.006, and x'+y'=1. M' includes one element from In, Zn, Ga, Sn, Zr, Ta, Ti, and Hf, or any combination of at least two elements; N' includes one element from Ce, Pr, Tb, Dy, and Yb, or any combination of at least two elements; The absolute value of the difference between the Fermi level of the photogenerated carrier quenching metal oxide semiconductor thin film and the Fermi level of the high-mobility metal oxide semiconductor thin film relative to the vacuum Fermi level is less than or equal to 0.5 eV. The expression for the absolute value of the difference between the Fermi level of the photogenerated carrier quenching metal-oxide-semiconductor thin film and the Fermi level of the high-mobility metal-oxide-semiconductor thin film relative to the vacuum Fermi level is as follows: |ΔE| = |(E CBMB -E VAC )- (E CBMA -E VAC )|; wherein |ΔE| is an absolute value of a difference of the Fermi level of the photo-generated carrier quenching metal oxide semiconductor thin film compared to the Fermi level of the high mobility metal oxide semiconductor thin film relative to a vacuum Fermi level; E CBMB is the Fermi level of the photo-generated carrier quenching metal oxide semiconductor thin film; E CBMA is the Fermi level of the high mobility metal oxide semiconductor thin film; E VAC is a vacuum Fermi level; The absolute value of the variable threshold voltage of the thin-film transistor formed from the metal oxide semiconductor thin film is less than or equal to 2V.

2. The metal oxide semiconductor thin film according to claim 1, characterized in that, The thickness of the high-mobility metal oxide semiconductor film is greater than or equal to 10 angstroms and less than or equal to 500 angstroms; and / or, the thickness of the photogenerated carrier quenching metal oxide semiconductor film is greater than or equal to 100 angstroms and less than or equal to 2000 angstroms.

3. The metal oxide semiconductor thin film according to claim 1, characterized in that, At least one surface of the high-mobility metal oxide semiconductor thin film is provided with the photogenerated carrier quenching metal oxide semiconductor thin film.

4. The metal oxide semiconductor thin film according to claim 3, characterized in that, The stacked structure formed by the high-mobility metal oxide semiconductor thin film and the photogenerated carrier quenching metal oxide semiconductor thin film includes any one of the following: AB stacked structure, BAB stacked structure, ABAB stacked structure, and ABBAB stacked structure. Wherein, A is the high-mobility metal oxide semiconductor thin film, and B is the photogenerated carrier quenching metal oxide semiconductor thin film.

5. The metal oxide semiconductor thin film according to claim 1, characterized in that, The chemical formula of the high-mobility metal oxide semiconductor thin film is (MO). x (NO) y Where 0.4≤x≤1, 0≤y≤0.6, and x+y=1; M includes one element from In, Sn, and Ga, or any combination of at least two elements; N includes one or any combination of at least two elements selected from Zn, Ga, Si, Al, Mo, W, Sc, Y, Hf, Zr, Ta, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Yb, Sb, and Bi.

6. The metal oxide semiconductor thin film according to claim 1, characterized in that, The carrier concentration of the high-mobility metal oxide semiconductor thin film is on the order of 10. 17 ~10 20 pcs / cubic centimeter; And / or, the carrier concentration of the photogenerated carrier-quenched metal-oxide-semiconductor thin film is on the order of 10. 16 ~10 19 Items per cubic centimeter.

7. The metal oxide semiconductor thin film according to claim 1, characterized in that, The carrier mobility of the high-mobility metal-oxide-semiconductor thin film is greater than or equal to 30 cm⁻¹. 2 / Vs.

8. A thin-film transistor, characterized in that, Includes the metal oxide semiconductor thin film according to any one of claims 1-7.

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