Defect state oxide thin film, photoelectric oxide thin film transistor and preparation method thereof

Abstract

The invention relates to the field of semiconductors, and discloses a defect-state oxide thin film, a photoelectric oxide thin film transistor and a preparation method thereof. The preparation method of the defect-state oxide thin film comprises the following steps: performing hydrogen-containing gas treatment in the process of preparing the oxide thin film by adopting an atomic layer deposition method to obtain the defect-state oxide thin film; or, after the oxide thin film is prepared, hydrogen-containing plasma treatment is carried out, and the defect-state oxide thin film is obtained. The preparation method of the defect-state oxide thin film is used for preparing the defect-state oxide thin film, hydrogen-containing gas treatment is carried out in the preparation process of the oxide thin film, hydrogen-containing plasma treatment can also be carried out after the oxide thin film is prepared, and the purpose of introducing a defect state into the oxide thin film is achieved; and forming a defect-state oxide film. According to the method, the defect mode gap can be introduced in the forbidden band width, so that the visible light absorption range is widened, and the photoelectric oxide thin film transistor has response in the visible light range.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a defective oxide thin film, a photoelectric oxide thin film transistor, and a preparation method thereof. Background Art

[0002] As modern society enters the era of informatization and intelligence, a series of intelligent applications represented by autonomous driving, intelligent robots, image / speech recognition, natural language translation, and data mining are constantly emerging, and the amount of data shows an explosive growth. The processing of ultra-large amounts of data poses challenges to computing systems. In the traditional von Neumann-based computing architecture, due to the separation of the central processing unit and the memory, the frequent data exchange between the two has become a constraint, resulting in the "memory wall" problem. In recent years, the miniaturization of silicon transistors has also faced physical limits, and Moore's law is approaching saturation. To break through these bottlenecks, monolithic three-dimensional integration that combines sensing, storage, and computing is a potential solution. Among them, oxide (such as indium gallium zinc oxide, indium oxide, zinc oxide, etc.) thin film transistors are a powerful technology for realizing monolithic three-dimensional integration due to their low thermal budget (<400 °C), mature large-scale deposition process, compatibility with subsequent processes, and good electrical properties such as extremely low leakage current and high carrier mobility.

[0003] Among them, the photoelectric oxide thin film transistor can be integrated with the memory-computation unit to realize a sense-memory-computation integrated system that can simulate human vision, significantly improving computing power and reducing power consumption. However, due to the relatively wide bandgap (>3.0 eV) of the currently commonly used oxide channel materials, they only respond to the ultraviolet band. In actual applications, visible light is mainly used, so it is necessary to expand the light response of the wide-bandgap oxide thin film transistor to the visible light band (400 - 700 nm) and longer wavelengths. Summary of the Invention

[0004] The present invention discloses a defective oxide thin film, a photoelectric oxide thin film transistor, and a preparation method thereof, which are used to increase the visible spectrum absorption range.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a preparation method of a defective oxide thin film, including:

[0007] During the process of preparing the oxide thin film by atomic layer deposition, hydrogen-containing gas treatment is performed to obtain a defective oxide thin film; or, after the oxide thin film is prepared, hydrogen-containing plasma treatment is performed to obtain a defective oxide thin film.

[0008] In the method for preparing the above defective state oxide film, by performing hydrogen-containing gas treatment during the preparation process of the oxide film or performing hydrogen-containing plasma treatment after the oxide film is prepared, the purpose of introducing defective states into the oxide film is achieved. The introduction of hydrogen can disrupt the defect balance in the oxide film and introduce defect energy levels within the bandgap, thereby broadening the visible light absorption range and enabling the prepared optoelectronic oxide thin film transistor to have a response in the visible light range.

[0009] In some embodiments, performing hydrogen-containing gas treatment during the process of preparing the oxide film by atomic layer deposition to obtain a defective state oxide film includes:

[0010] During the process of preparing the oxide film by thermal atomic layer deposition, mixing a certain proportion of hydrogen and / or ammonia into an inert carrier gas;

[0011] And / or, during the process of preparing the oxide film by thermal atomic layer deposition, purging with a hydrogen-containing gas after the normal oxygen source pulse and purge are completed.

[0012] In some embodiments, performing hydrogen-containing gas treatment during the process of preparing the oxide film by atomic layer deposition to obtain a defective state oxide film further includes:

[0013] During the process of preparing the oxide film by plasma-enhanced atomic layer deposition, mixing a certain proportion of hydrogen and / or ammonia into an inert carrier gas;

[0014] And / or, during the process of preparing the oxide film by plasma-enhanced atomic layer deposition, purging with a hydrogen-containing gas after the normal oxygen source pulse and purge;

[0015] And / or, during the process of preparing the oxide film by plasma-enhanced atomic layer deposition, purging with a hydrogen-containing plasma after the plasma oxygen source pulse and purge.

[0016] In some embodiments, the hydrogen-containing gas includes at least one of hydrogen, ammonia, nitrogen-hydrogen mixed gas, nitrogen-ammonia mixed gas, argon-hydrogen mixed gas, and argon-ammonia mixed gas;

[0017] And / or, the hydrogen-containing plasma includes at least one of nitrogen-hydrogen mixed gas, nitrogen-ammonia mixed gas, argon-hydrogen mixed gas, and argon-ammonia mixed gas.

[0018] In some embodiments, after the oxide film is prepared, performing hydrogen-containing plasma treatment to obtain a defective state oxide film includes:

[0019] After the oxide film is prepared by plasma-enhanced atomic layer deposition, performing hydrogen-containing plasma treatment.

[0020] In some embodiments, the hydrogen-containing plasma includes at least one of a nitrogen-hydrogen mixed gas, a nitrogen-ammonia mixed gas, an argon-hydrogen mixed gas, and an argon-ammonia mixed gas.

[0021] In a second aspect, the present invention further provides a defective oxide thin film prepared by the method described in any one of the first aspects.

[0022] In a third aspect, the present invention further provides a photoelectric oxide thin film transistor, including:

[0023] A substrate;

[0024] A channel layer formed on the substrate;

[0025] A light absorption layer formed on a side of the channel layer away from the substrate, the light absorption layer including the defective oxide thin film described in the second aspect.

[0026] In some embodiments, the photoelectric oxide thin film transistor further includes:

[0027] A defect adjustment layer formed on a side of the light absorption layer away from the channel layer;

[0028] The defect density of the defect adjustment layer is not higher than that of the channel layer.

[0029] In some embodiments, the material of the channel layer includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide;

[0030] Alternatively, the material of the defective oxide thin film includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide;

[0031] Alternatively, the material of the defect adjustment layer includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide.

[0032] In a fourth aspect, the present invention further provides a method for manufacturing a photoelectric oxide thin film transistor, including:

[0033] Providing a substrate;

[0034] Preparing a channel layer on the substrate;

[0035] Preparing a defective oxide thin film on a side of the channel layer away from the substrate to form a light absorption layer;

[0036] The defective oxide thin film is prepared by the method described in any one of the first aspects.

[0037] In some embodiments, the method further includes:

[0038] An oxide thin film is prepared on the side of the light absorption layer facing away from the substrate to form a defect adjustment layer; the defect density of the defect adjustment layer is not higher than that of the channel layer. Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of an optoelectronic oxide thin film transistor;

[0040] Figure 2 It is a schematic diagram of a preparation method of a defect state oxide thin film provided by an embodiment of the present invention;

[0041] Figure 3 It is a schematic diagram of another preparation method of a defect state oxide thin film provided by an embodiment of the present invention;

[0042] Figure 4 It is a schematic diagram of another preparation method of a defect state oxide thin film provided by an embodiment of the present invention;

[0043] Figure 5 It is a schematic diagram of another preparation method of a defect state oxide thin film provided by an embodiment of the present invention;

[0044] Figure 6 It is a schematic diagram of another preparation method of a defect state oxide thin film provided by an embodiment of the present invention;

[0045] Figure 7 It is a schematic diagram of another preparation method of a defect state oxide thin film provided by an embodiment of the present invention;

[0046] Figure 8 It is a flowchart of another preparation method of a defect state oxide thin film provided by an embodiment of the present invention;

[0047] Figure 9 It is a schematic structural diagram of an optoelectronic oxide thin film transistor provided by an embodiment of the present invention;

[0048] Figure 10 It is a schematic structural diagram of another optoelectronic oxide thin film transistor provided by an embodiment of the present invention;

[0049] Figure 11 and Figure 12 It is a transfer characteristic curve graph under illumination of ultraviolet light (365 nm) and green light (520 nm) wavelengths before and after N2 / H2 plasma treatment;

[0050] Figure 13 and Figure 14 It is a graph of the relationship between current and time under illumination of ultraviolet light (365 nm) and green light (520 nm) wavelengths when the number of light pulses is 50;

[0051] Icon: 1-substrate; 2-bottom gate; 3-gate dielectric layer; 4-active layer; 5-passivation layer; 6-source; 7-drain; 41-channel layer; 101-substrate; 102-bottom gate; 103-gate dielectric layer; 104-multilayer film structure; 105-conductive layer; 106-passivation layer; 107-source; 108-drain; 104A-channel layer; 104B-light absorption layer; 104C-defect adjustment layer. DETAILED DESCRIPTION

[0052] First, let me introduce the application scenarios of this application: Figure 1 As shown, a thin film transistor includes: a substrate 1; a bottom gate 2 formed on one side of the substrate 1; a gate dielectric layer 3 formed on the side of the bottom gate 2 away from the substrate 1; an active layer 4 formed on the side of the gate dielectric layer 3 away from the gate 2; a passivation layer 5 formed on the active layer 4 away from the gate dielectric layer 3; a source electrode 6 formed on the side of the passivation layer 5 away from the active layer 4, the source electrode 6 and the active layer 4 are connected through a metal via; a drain electrode 7 formed on the side of the passivation layer 5 away from the active layer 4, the drain electrode 7 and the active layer 4 are connected through a metal via. The active layer 4 includes a channel layer 41 located between the source electrode 6 and the drain electrode 7. The band gap of the channel layer 41 is usually more than 3eV, so it can only absorb short-wave photons such as ultraviolet light. On the other hand, in order to improve the performance of the sensing, storage and computing integrated system, the size of the photoelectric oxide thin film transistor needs to be continuously miniaturized. Although physical vapor deposition is a mature method for preparing oxide thin film transistors in the display industry, this method is difficult to ensure the thickness uniformity of the film at advanced nodes. The atomic layer deposition (ALD) preparation technology can ensure the uniformity of low-thickness (several nanometers) films and conformality in complex structures. Therefore, it is an excellent means to prepare high-performance photoelectric oxide thin-film transistors at advanced nodes.

[0053] Based on the above application scenarios, the embodiments of the present application provide a defective oxide film, a photoelectric oxide thin film transistor and a preparation method thereof, which are used to improve the absorption range of the visible spectrum.

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may represent A or B; "and / or" in the text is only a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality" means two or more than two.

[0055] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying or suggesting relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0056] In a first aspect, an embodiment of the present invention provides a method for preparing a defective oxide film, including:

[0057] During the process of preparing the oxide film by atomic layer deposition, hydrogen-containing gas treatment is performed to obtain a defective oxide film; or, after the oxide film is prepared, hydrogen plasma treatment is performed to obtain a defective oxide film.

[0058] The above method for preparing a defective oxide film is used to prepare a defective oxide film. By performing hydrogen-containing gas treatment during the preparation process of the oxide film, the purpose of introducing defective states in the oxide film is achieved, and a defective oxide film is formed. The defective oxide film can be directly used as a channel layer in an optoelectronic oxide thin film transistor or formed on the side of the channel layer away from the substrate. The introduction of hydrogen can disrupt the defect balance in the oxide film and introduce defect energy levels within the bandgap, thereby broadening the visible light absorption range and enabling the optoelectronic oxide thin film transistor to have a response in the visible light range.

[0059] Of course, the above method for preparing the defective oxide thin film can also perform hydrogen-containing plasma treatment after the oxide thin film is prepared to introduce defective states into the oxide thin film and form a defective oxide thin film. When the defective oxide thin film is applied to an optoelectronic oxide thin film transistor, it can directly serve as the channel layer or be formed on the side of the channel layer facing away from the substrate. The introduction of hydrogen can disrupt the defect balance in the oxide thin film, introduce defective state gaps within the bandgap, thereby broadening the visible light absorption range and enabling the optoelectronic oxide thin film transistor to have a response in the visible light range.

[0060] In some embodiments, during the process of preparing the oxide thin film by atomic layer deposition, hydrogen-containing gas treatment is performed to obtain a defective oxide thin film, including:

[0061] During the process of preparing the oxide thin film by thermal atomic layer deposition, a certain proportion of hydrogen and / or ammonia is mixed into the inert carrier gas;

[0062] And / or, during the process of preparing the oxide thin film by thermal atomic layer deposition, after the normal oxygen source pulse and purge are completed, hydrogen-containing gas purge is performed.

[0063] In one possible implementation, as Figure 2 shown, during the process of preparing the oxide thin film by thermal atomic layer deposition, a certain proportion of hydrogen and / or ammonia is mixed into the inert carrier gas. The proportion of hydrogen and / or ammonia mixed can be adjusted according to the defect density of the oxide thin film prepared by thermal atomic layer deposition. It should be noted that during the process of preparing the oxide thin film by thermal atomic layer deposition, the carrier gas can be a conventional inert gas, or a gas containing doping elements such as nitrogen, hydrogen, sulfur (such as hydrogen, hydrogen sulfide, ammonia, etc.), or a mixture of the above gases and conventional inert gases.

[0064] In one possible implementation, as Figure 3 shown, during the process of preparing the oxide thin film by thermal atomic layer deposition, after the normal oxygen source pulse and purge are completed, hydrogen-containing gas purge is performed. The hydrogen-containing gas can be a gas containing doping elements such as nitrogen, hydrogen, sulfur (such as hydrogen, hydrogen sulfide, ammonia, etc.), or a mixture of the above gases and conventional inert gases. It should be noted that the additional hydrogen-containing gas purge step can be performed after each cycle or several cycles.

[0065] In one possible implementation, as Figure 4As shown, during the process of preparing an oxide film by thermal atomic layer deposition, a certain proportion of hydrogen and / or ammonia is mixed into an inert carrier gas; and, after the normal oxygen source pulse and purge are completed, a hydrogen-containing gas is used for purging. The hydrogen-containing gas can be a gas containing doping elements such as nitrogen, hydrogen, sulfur, etc. (such as hydrogen, hydrogen sulfide, ammonia, etc.), or a mixture of the above gases and a conventional inert gas.

[0066] In some embodiments, during the process of preparing an oxide film by atomic layer deposition and performing hydrogen-containing gas treatment to obtain a defective oxide film, it further includes:

[0067] During the process of preparing an oxide film by plasma-enhanced atomic layer deposition, a certain proportion of hydrogen and / or ammonia is mixed into an inert carrier gas;

[0068] and / or, during the process of preparing an oxide film by plasma-enhanced atomic layer deposition, after the normal oxygen source pulse and purge, a hydrogen-containing gas is used for purging;

[0069] and / or, during the process of preparing an oxide film by plasma-enhanced atomic layer deposition, after the plasma oxygen source pulse and purge, a hydrogen-containing plasma is used for purging.

[0070] In a possible implementation manner, as Figure 5 shown, during the process of preparing an oxide film by plasma-enhanced atomic layer deposition, a certain proportion of hydrogen and / or ammonia is mixed into an inert carrier gas. The proportion of hydrogen and / or ammonia mixed can be adjusted according to the defect density of the oxide film prepared by plasma-enhanced atomic layer deposition. It should be noted that during the process of preparing an oxide film by plasma-enhanced atomic layer deposition, the carrier gas can be a conventional inert gas, or a gas containing doping elements such as nitrogen, hydrogen, sulfur, etc. (such as hydrogen, hydrogen sulfide, ammonia, etc.), or a mixture of the above gases and a conventional inert gas.

[0071] In a possible implementation manner, during the process of preparing an oxide film by plasma-enhanced atomic layer deposition, after the normal oxygen source pulse and purge are completed, a hydrogen-containing gas is used for purging. The hydrogen-containing gas can be a gas containing doping elements such as nitrogen, hydrogen, sulfur, etc. (such as hydrogen, hydrogen sulfide, ammonia, etc.), or a mixture of the above gases and a conventional inert gas. It should be noted that the additional hydrogen-containing gas purge step can be performed after each cycle or several cycles.

[0072] In a possible implementation manner, as Figure 6As shown, during the process of preparing an oxide thin film by plasma-enhanced atomic layer deposition, after the plasma oxygen source pulse and purge, a hydrogen-containing plasma purge is performed. The hydrogen-containing plasma can be a mixture of a plasma and a gas containing doping elements such as nitrogen, hydrogen, sulfur (such as hydrogen gas, hydrogen sulfide, ammonia gas, etc.). It should be noted that the hydrogen-containing plasma purge can be performed after each cycle or several cycles.

[0073] In one possible implementation, as Figure 7 shown, during the process of preparing an oxide thin film by plasma-enhanced atomic layer deposition, a certain proportion of hydrogen gas and / or ammonia gas is mixed into an inert carrier gas. And, after the normal oxygen source pulse and purge are completed, a hydrogen-containing gas purge is performed. On this basis, after the plasma oxygen source pulse and purge, a hydrogen-containing plasma purge is performed. It should be noted that the hydrogen-containing plasma purge step can follow the aforementioned hydrogen-containing gas purge step, or can replace the aforementioned hydrogen-containing gas purge step. That is to say, the hydrogen-containing gas purge step and the hydrogen-containing plasma purge step are in an and / or relationship.

[0074] In some embodiments, the hydrogen-containing gas includes at least one of hydrogen gas, ammonia gas, nitrogen-hydrogen mixed gas, nitrogen-ammonia mixed gas, argon-hydrogen mixed gas, and argon-ammonia mixed gas;

[0075] and / or, the hydrogen-containing plasma includes at least one of nitrogen-hydrogen mixed gas, nitrogen-ammonia mixed gas, argon-hydrogen mixed gas, and argon-ammonia mixed gas.

[0076] Wherein: the nitrogen-hydrogen mixed gas is a mixed gas of nitrogen and hydrogen, the nitrogen-ammonia mixed gas is a mixed gas of nitrogen and ammonia; the argon-hydrogen mixed gas is a mixed gas of argon and hydrogen; the argon-ammonia mixed gas is a mixed gas of argon and ammonia.

[0077] In some embodiments, after the oxide thin film is prepared, a hydrogen-containing plasma treatment is performed to obtain a defective oxide thin film, including:

[0078] After the oxide thin film is prepared by plasma-enhanced atomic layer deposition, a hydrogen-containing plasma treatment is performed.

[0079] In one possible implementation, as Figure 8 shown, a method for preparing a defective oxide thin film specifically includes:

[0080] S801. Prepare an oxide thin film by plasma-enhanced atomic layer deposition;

[0081] S802. Perform a hydrogen-containing plasma treatment on the obtained oxide thin film.

[0082] After preparing the oxide film by plasma-enhanced atomic layer deposition, an additional post-treatment step is performed on the film using the plasma of the plasma-enhanced atomic layer deposition method to introduce interstitial states, avoiding the use of other equipment. This can reduce the contamination of the sample during transfer due to contact with the outside world and significantly reduce the equipment cost.

[0083] In the above S802, the hydrogen-containing plasma treatment can specifically be doping atmosphere heat treatment or doping atmosphere plasma treatment after the deposition of the oxide film to achieve the introduction of defects in the oxide film.

[0084] In some embodiments, the hydrogen-containing plasma includes at least one of a nitrogen-hydrogen mixed gas, a nitrogen-ammonia mixed gas, an argon-hydrogen mixed gas, and an argon-ammonia mixed gas. Among them: the nitrogen-hydrogen mixed gas is a mixed gas of nitrogen and hydrogen, the nitrogen-ammonia mixed gas is a mixed gas of nitrogen and ammonia; the argon-hydrogen mixed gas is a mixed gas of argon and hydrogen; the argon-ammonia mixed gas is a mixed gas of argon and ammonia.

[0085] An embodiment of the first aspect of the present invention provides a method for preparing a defective oxide film. Specifically, by introducing a hydrogen-containing carrier gas or / and a hydrogen-containing plasma source during the atomic layer deposition process and adding an additional hydrogen-containing plasma post-treatment after the deposition of the oxide film, defective states are introduced into the oxide film, thereby increasing the visible spectrum absorption range.

[0086] In a second aspect, an embodiment of the present invention also provides a defective oxide film prepared by any method in the embodiments of the first aspect. By introducing hydrogen during the preparation process of this defective oxide film, when the defective oxide film is applied to an optoelectronic oxide thin film transistor, the introduction of hydrogen can disrupt the defect balance in the channel layer and introduce defect energy levels within the bandgap, thereby increasing the visible spectrum absorption range.

[0087] In a third aspect, an embodiment of the present invention also provides an optoelectronic oxide thin film transistor, including:

[0088] A substrate 101;

[0089] A channel layer 104A formed on the substrate 101;

[0090] An optical absorption layer 104B formed on the side of the channel layer 104A facing away from the substrate 101, and the optical absorption layer 104B includes a defective oxide film as in the embodiment of the second aspect.

[0091] In a possible implementation, as Figure 9As shown in the figure, a thin-film transistor includes: a substrate 101; a bottom gate 102 formed on one side of the substrate 101; a gate dielectric layer 103 formed on the side of the bottom gate 102 facing away from the substrate 101; a multi-layer film structure 104 formed on the side of the gate dielectric layer 103 facing away from the gate; a passivation layer 106 formed on the multi-layer film structure 104 facing away from the gate dielectric layer 103; a source electrode 107 formed on the side of the passivation layer 106 facing away from the multi-layer film structure 104, and the source electrode 107 is connected to the multi-layer film structure 104 through a metal via and a conductive layer 105; a drain electrode 108 formed on the side of the passivation layer 106 facing away from the multi-layer film structure 104, and the drain electrode 108 is connected to the multi-layer film structure 104 through a metal via and a conductive layer 105. The multi-layer film structure 104 includes a channel layer 104A and a light absorption layer 104B located between the source electrode 107 and the drain electrode 108. The bandgap of the channel layer 104A usually exceeds 3 eV, so it can only absorb short-wavelength photons such as ultraviolet light, while the defective oxide film of the light absorption layer 104B has a response in the visible light range by introducing defect states during the ALD deposition process for the aforementioned channel layer 104A. The introduction of defect states can be achieved by several methods such as using a hydrogen-containing carrier gas during the ALD deposition process, mixing a hydrogen-containing gas in the plasma gas, and performing additional hydrogen-containing plasma treatment after the film deposition. The introduction of hydrogen can disrupt the defect balance in the above-mentioned channel thin film, introduce defect state gaps within the bandgap, thereby broadening the visible light absorption range.

[0092] It should be noted that the substrate 101 can be silicon-based or glass-based, etc. The material of the bottom gate 102 is usually metal or transparent conductive oxide, and can be obtained by methods such as sputtering, evaporation, ALD, etc.; the gate dielectric is usually silicon dioxide (SiO x ), aluminum oxide (Al2O3), hafnium dioxide (HfO x ), hafnium zirconium oxide (HfZrO) and other high dielectric constant thin film materials, and its preparation methods are mainly ALD, plasma enhanced chemical vapor deposition, etc. Deposited on the gate dielectric layer 103 is a multi-layer film structure 104 prepared by ALD, which includes a channel layer 104A and a light absorption layer 104B with visible light response. Exemplarily, the channel layer 104A can be a channel thin film prepared by ALD, such as indium gallium zinc oxide (IGZO), indium tin oxide (ITO), indium oxide (In2O3), zinc oxide (ZnO), etc. The conductive layer 105 is a highly conductive region, which can reduce the contact resistance between the channel layer 104A and the source electrode 107 / drain electrode 108, and this can be achieved by doping with metals such as aluminum (Al), magnesium (Mg), titanium (Ti), calcium (Ca), etc. or post-treatment methods such as plasma (argon (Ar), helium (He), fluorine (F), etc.) treatment. The passivation layer 106 is mainly a dielectric material such as silicon dioxide (SiO x ), silicon nitride (SiN), silicon oxynitride (SiO x Ny ), aluminum oxide (Al2O3), etc., whose function can be the protection / passivation layer 106 of the channel layer 104A or the etch stop layer.

[0093] In some embodiments, the optoelectronic oxide thin film transistor further includes:

[0094] A defect adjustment layer 104C formed on the side of the light absorption layer 104B away from the channel layer 104A;

[0095] The defect density of the defect adjustment layer 104C is not higher than that of the channel layer 104A.

[0096] In a possible implementation manner, as Figure 10 shown, a thin film transistor includes: a substrate 101; a bottom gate 102 formed on one side of the substrate 101; a gate dielectric layer 103 formed on the side of the bottom gate 102 away from the substrate 101; a multi-layer film structure 104 formed on the side of the gate dielectric layer 103 away from the gate; a passivation layer 106 formed on the side of the multi-layer film structure 104 away from the gate dielectric layer 103; a source electrode 107 formed on the side of the passivation layer 106 away from the multi-layer film structure 104, and the source electrode 107 is connected to the multi-layer film structure 104 through a metal via and a conductive layer 105; a drain electrode 108 formed on the side of the passivation layer 106 away from the multi-layer film structure 104, and the drain electrode 108 is connected to the multi-layer film structure 104 through a metal via and a conductive layer 105. The multi-layer film structure 104 includes a channel layer 104A, a light absorption layer 104B, and a defect adjustment layer 104C located between the source electrode 107 and the drain electrode 108.

[0097] It should be noted that the defect state oxide thin film can broaden the visible light absorption range, and its abundant internal defects may damage its transistor electrical performance. Therefore, a channel material with a low defect density can be considered to be further stacked to form the defect adjustment layer 104C, and the defect density of the defect adjustment layer 104C is not higher than that of the channel layer 104A, and finally, the requirements of the electrical performance of the device for actual applications are mainly met. In addition, if the channel layer 104A and the light absorption layer 104B can already meet the requirements, the defect adjustment layer 104C may not be deposited.

[0098] In some embodiments, the material of the channel layer 104A includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide;

[0099] Alternatively, the material of the defect state oxide thin film includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide;

[0100] Alternatively, the material of the defect adjustment layer 104C includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide.

[0101] It should be noted that the oxide materials of the channel layer 104A, the light absorption layer 104B, and the defect adjustment layer 104C can be the same, or a combination of two or three different materials. Transistors prepared from the channel layer 104A have different electrical properties. For example, ZnO has a relatively high mobility, but its chemical stability is inferior to that of In2O3. According to different requirements of the applications, different combinations of oxide materials can be used to achieve the required performance.

[0102] In a possible implementation, an IGZO thin film transistor is prepared, where the channel layer is obtained by sputtering. The channel layer is subjected to plasma treatment using a N2 / H2 mixed gas in plasma-enhanced ALD, where the plasma power is 500 W, the plasma treatment times are 60 seconds and 100 seconds respectively, and the temperature of the channel layer is set at 200 °C. Figure 11 and Figure 12 It can be seen that before the plasma treatment, the IGZO thin film transistor has almost no response to green light (520 nm), but has a response to ultraviolet light (365 nm). After the N2 / H2 plasma treatment, the responses of the device to both green light and ultraviolet light are significantly enhanced. By applying a light pulse of 1 Hz to the transistor after the N2 / H2 plasma treatment using light of the corresponding wavelength, significantly enhanced long / short-term optoelectronic synaptic characteristics can be obtained, as shown in Figure 13 and Figure 14 The above results prove that post-treatment of the prepared IGZO thin film with N2 / H2 plasma can effectively introduce defect states, thereby expanding its light response from ultraviolet light to visible light, which verifies the feasibility and rationality of Figure 8 from the side.

[0103] Fourthly, an embodiment of the present invention further provides a method for preparing an optoelectronic oxide thin film transistor, including:

[0104] Providing a substrate;

[0105] Preparing a channel layer on the substrate;

[0106] Preparing a defect state oxide thin film on the side of the channel layer away from the substrate to form a light absorption layer;

[0107] The defect state oxide thin film is prepared by any one of the methods in the first aspect of the embodiment.

[0108] It should be noted that the materials of the channel layer / light absorption layer are prepared by a thermal method or a plasma-enhanced ALD method. The gate dielectric layer is prepared by ALD, and other film layers such as the gate, source / drain, and passivation layer can be prepared by ALD, or can also be prepared by other methods such as sputtering and plasma-enhanced chemical vapor deposition.

[0109] An embodiment of the present invention provides a method for preparing a photoelectric thin film transistor with visible light response prepared by atomic layer deposition. Specifically, by introducing a hydrogen-containing carrier gas or / and a hydrogen-containing plasma source during the ALD process and adding an additional hydrogen-containing plasma post-treatment after the ALD thin film deposition process, defect states are introduced into the light absorption layer, thereby increasing the visible spectrum absorption range.

[0110] In some embodiments, the method further includes:

[0111] Preparing an oxide film on the side of the light absorption layer facing away from the substrate to form a defect adjustment layer; the defect density of the defect adjustment layer is not higher than that of the channel layer.

[0112] An embodiment of the present invention proposes a method for in-situ introducing the expansion of visible light absorption during the ALD preparation process. Compared with physical deposition methods (such as sputtering, etc.), ALD has excellent superiority in the process of preparing thin films with extremely small scales. Therefore, the method proposed by the embodiment of the present invention will have better process stability in the back-end integration of photoelectric oxide thin film transistors after the front-end process of advanced nodes. In addition, the method proposed by the embodiment of the present invention can complete the deposition of the channel layer and the light absorption layer using the same ALD device, avoiding the use of other devices, which can reduce the contamination of the sample during the transfer process due to contact with the outside world and significantly reduce the equipment cost.

[0113] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A method for preparing a defective oxide thin film, characterized in that, Including: During the process of preparing an oxide thin film by atomic layer deposition, hydrogen-containing gas treatment is performed to obtain a defective oxide thin film; or, after the oxide thin film is prepared, hydrogen-containing plasma treatment is performed to obtain a defective oxide thin film.

2. The method according to claim 1, characterized in that, The hydrogen-containing gas treatment during the process of preparing an oxide thin film by atomic layer deposition to obtain a defective oxide thin film includes: During the process of preparing an oxide thin film by thermal atomic layer deposition, a certain proportion of hydrogen and / or ammonia is mixed into an inert carrier gas; And / or, during the process of preparing an oxide thin film by thermal atomic layer deposition, after the normal oxygen source pulse and purge are completed, hydrogen-containing gas purge is performed.

3. The method according to claim 1, wherein The hydrogen-containing gas treatment during the process of preparing an oxide thin film by atomic layer deposition to obtain a defective oxide thin film further includes: During the process of preparing an oxide thin film by plasma-enhanced atomic layer deposition, a certain proportion of hydrogen and / or ammonia is mixed into an inert carrier gas; And / or, during the process of preparing an oxide thin film by plasma-enhanced atomic layer deposition, after the normal oxygen source pulse and purge, hydrogen-containing gas purge is performed; And / or, during the process of preparing an oxide thin film by plasma-enhanced atomic layer deposition, after the plasma oxygen source pulse and purge, hydrogen-containing plasma purge is performed.

4. The method according to claim 2 or 3, characterized in that, The hydrogen-containing gas includes at least one of hydrogen, ammonia, nitrogen-hydrogen mixed gas, nitrogen-ammonia mixed gas, argon-hydrogen mixed gas, and argon-ammonia mixed gas; And / or, the hydrogen-containing plasma includes at least one of nitrogen-hydrogen mixed gas, nitrogen-ammonia mixed gas, argon-hydrogen mixed gas, and argon-ammonia mixed gas.

5. The method according to claim 1, wherein After the oxide thin film is prepared, hydrogen-containing plasma treatment is performed to obtain a defective oxide thin film, including: After the oxide thin film is prepared by plasma-enhanced atomic layer deposition, hydrogen-containing plasma treatment is performed.

6. The method according to claim 5, wherein The hydrogen-containing plasma includes at least one of nitrogen-hydrogen mixed gas, nitrogen-ammonia mixed gas, argon-hydrogen mixed gas, and argon-ammonia mixed gas.

7. A defective oxide thin film, characterized in that, Prepared by the method according to any one of claims 1-6.

8. An optoelectronic oxide thin film transistor, characterized in that, Including: A substrate; A channel layer formed on the substrate; A light absorption layer formed on the side of the channel layer facing away from the substrate, the light absorption layer including the defective oxide thin film according to claim 7.

9. The optoelectronic oxide thin film transistor according to claim 8, wherein, Further including: A defect adjustment layer formed on the side of the light absorption layer facing away from the channel layer; The defect density of the defect adjustment layer is not higher than that of the channel layer.

10. The optoelectronic oxide thin film transistor according to claim 9, wherein The material of the channel layer includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide; Or, the material of the defective oxide thin film includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide; Or, the material of the defect adjustment layer includes at least one of indium gallium zinc oxide, indium tin oxide, indium oxide, and zinc oxide.

11. A method for preparing an optoelectronic oxide thin film transistor, characterized in that, Including: Providing a substrate; Preparing a channel layer on the substrate; Preparing a defective oxide thin film on the side of the channel layer facing away from the substrate to form a light absorption layer; The defective oxide thin film is prepared by the method according to any one of claims 1-6.

12. The method according to claim 11, wherein Further including: Preparing an oxide thin film on the side of the light absorption layer facing away from the substrate to form a defect adjustment layer; The defect density of the defect adjustment layer is not higher than that of the channel layer.

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