Preparation methods of indium gallium zinc oxide film and indium gallium zinc oxide transistor

Abstract

The invention relates to a preparation method of an indium gallium zinc oxide film and an indium gallium zinc oxide transistor. The preparation method of the indium gallium zinc oxide film comprises the following steps: providing a substrate; forming an indium gallium zinc oxide initial layer on the substrate; and carrying out acid pickling on the indium gallium zinc oxide initial layer through an acid pickling solution to form the indium gallium zinc oxide thin film. According to the embodiment of the invention, the contact resistance between the indium gallium zinc oxide thin film and the electrodes (the source electrode and the drain electrode) can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a method for preparing an indium gallium zinc oxide thin film and an indium gallium zinc oxide transistor. Background Art

[0002] Indium gallium zinc oxide (IGZO) thin films have excellent properties such as high mobility, good stability, and simple manufacturing process, making IGZO indium gallium zinc oxide transistors the focus of attention.

[0003] However, the surface morphology of indium gallium zinc oxide thin films prepared by some existing methods is not flat and smooth enough, and the surface defect density is large, which is not conducive to the formation of ohmic contact, resulting in a large contact resistance between the source and drain regions and the electrodes of the IGZO indium gallium zinc oxide transistor. Summary of the invention

[0004] Based on this, the embodiments of the present application provide a method for preparing an indium gallium zinc oxide thin film and an indium gallium zinc oxide transistor capable of reducing contact resistance.

[0005] A method for preparing an indium gallium zinc oxide thin film, comprising:

[0006] providing a substrate;

[0007] forming an initial indium gallium zinc oxide layer on the substrate;

[0008] The indium gallium zinc oxide initial layer is pickled with an acid pickling solution to form the indium gallium zinc oxide thin film.

[0009] In one embodiment, pickling the initial indium gallium zinc oxide layer with a pickling solution to form the indium gallium zinc oxide thin film includes:

[0010] The indium gallium zinc oxide initial layer is immersed in the acid cleaning solution to perform acid cleaning on the indium gallium zinc oxide initial layer.

[0011] In one embodiment, the indium gallium zinc oxide initial layer is formed by a solution method or a vapor phase deposition method.

[0012] In one embodiment, pickling the initial indium gallium zinc oxide layer with a pickling solution to form the indium gallium zinc oxide thin film includes:

[0013] A pickling solution is sprayed onto the indium gallium zinc oxide initial layer, and the substrate on which the indium gallium zinc oxide initial layer is formed is rotated to pickle the indium gallium zinc oxide initial layer.

[0014] In one embodiment, the indium gallium zinc oxide initial layer is formed by a vapor deposition method, and in a deposition chamber for forming the indium gallium zinc oxide initial layer, the indium gallium zinc oxide initial layer is in-situ acid-washed.

[0015] In one embodiment, the indium gallium zinc oxide initial layer includes n initial sublayers formed sequentially, and the indium gallium zinc oxide thin film includes n thin film sublayers, where n is a positive integer greater than 1.

[0016] The step of forming an initial indium gallium zinc oxide layer on the substrate comprises:

[0017] The i-th initial sublayer is formed on the i-1-th thin film sublayer, where i is a positive integer, and k≤i≤n, 2≤k <n;

[0018] The indium gallium zinc oxide initial layer is pickled with a pickling solution to form the indium gallium zinc oxide thin film, comprising:

[0019] The i-th initial sub-layer is pickled with a pickling solution to form an i-th thin film sub-layer.

[0020] In one embodiment, forming an initial indium gallium zinc oxide layer on the substrate further comprises:

[0021] The first k-1 initial sub-layers are formed on the substrate, and the first k-1 initial sub-layers that are not acid-washed form the first k-1 thin film sub-layers.

[0022] In one embodiment, the thickness of the first k-1 initial sub-layers is 10nm-20nm, and the total thickness of the remaining initial sub-layers is 20nm-30nm.

[0023] In one embodiment, when pickling each of the initial sub-layers, the acidity and / or concentration of the pickling solution are not completely the same.

[0024] In one embodiment, the pickling solution is a medium-strong acid pickling solution.

[0025] In one embodiment, the medium-strong acid includes any one or more of tartaric acid, sulfurous acid, pyruvic acid, oxalic acid, nitrous acid, hydrofluoric acid and formic acid.

[0026] In one embodiment, the medium-strong acid pickling solution is a medium-strong acid diluted with deionized water, and the ratio of deionized water to acid is 10:1, and the pickling time is 10s-2min.

[0027] In one embodiment, the base includes a substrate and an isolation dielectric layer, and the forming of an indium gallium zinc oxide initial layer on the base includes:

[0028] The indium gallium zinc oxide initial layer is formed on the isolation dielectric layer.

[0029] A method for preparing an indium gallium zinc oxide transistor, comprising:

[0030] Providing an indium gallium zinc oxide thin film as described in any one of the above items;

[0031] The indium gallium zinc oxide transistor is formed based on the indium gallium zinc oxide thin film.

[0032] In one embodiment, forming the indium gallium zinc oxide transistor based on the indium gallium zinc oxide thin film includes:

[0033] forming a source electrode and a drain electrode on the indium gallium zinc oxide thin film;

[0034] forming a gate dielectric layer and a gate on the indium gallium zinc oxide film between the source and the drain,

[0035] In the above-mentioned method for preparing the indium gallium zinc oxide film and the indium gallium zinc oxide transistor, when the indium gallium zinc oxide initial layer is pickled, the pickling solution can dissolve the oxygen on the surface of the indium gallium zinc oxide initial layer, thereby generating oxygen vacancies. The surface of the indium gallium zinc oxide film formed after pickling has oxygen vacancies, so that the indium gallium zinc oxide film can form a good contact with the electrode (source and drain) through the oxygen vacancies, thereby effectively reducing the contact resistance. When the pickling solution is a medium-strong acid pickling solution, the amorphous oxides of indium, gallium and zinc do not react with the medium-strong acid, so after being treated with the medium-strong acid, more oxygen vacancies will appear on the surface, which is more conducive to reducing the contact resistance.

[0036] Furthermore, after the initial indium gallium zinc oxide layer is pickled, the surface of the obtained indium gallium zinc oxide film can be smoother, that is, the surface roughness of the indium gallium zinc oxide film can be lower. At this time, the contact resistance can be further reduced.

[0037] At the same time, when the initial indium gallium zinc oxide layer is pickled, some of the oxygen vacancies generated on its surface can diffuse inward, thereby obtaining more oxygen vacancies. Therefore, the mobility of the indium gallium zinc oxide film formed after pickling can also be effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1It is a flow chart of a method for preparing an indium gallium zinc oxide thin film provided in an embodiment;

[0040] Figures 2 to 4 A schematic diagram of the cross-sectional structure of the structure obtained in each step of the method for preparing an indium gallium zinc oxide thin film provided in an embodiment;

[0041] Figure 5 Schematic diagram of the principle of oxygen vacancies generated when the initial layer of indium gallium zinc oxide is pickled;

[0042] Figures 6 to 8 A schematic diagram of the cross-sectional structure of the structure obtained in each step of the method for preparing an indium gallium zinc oxide thin film provided in another embodiment;

[0043] Fig. 9 Schematic diagram of the cross-sectional structure of an InGaZnO transistor provided in one embodiment.

[0044] Description of reference numerals:

[0045] 100-base, 110-substrate, 120-isolation dielectric layer, 201-indium gallium zinc oxide initial layer, 201a-initial sublayer, 200-indium gallium zinc oxide thin film, 200a-thin film sublayer, 300-indium gallium zinc oxide transistor, 301-source region, 302-drain region, 303-channel region, 310-gate dielectric layer, 320-gate, 330-source, 340-drain. DETAILED DESCRIPTION

[0046] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0048] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers, doping types and / or parts, these elements, components, regions, layers, doping types and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type or part from another element, component, region, layer, doping type or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer, doping type or part discussed below can be represented as a second element, component, region, layer or part.

[0049] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0050] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that when the terms "consisting of" and / or "comprising" are used in this specification, the presence of the features, integers, steps, operations, elements and / or parts can be determined, but the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups is not excluded. At the same time, when used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0051] In one embodiment, see Figure 1 , a method for preparing an indium gallium zinc oxide thin film is provided, comprising:

[0052] Step S10, providing a substrate 100;

[0053] Step S20, forming an indium gallium zinc oxide initial layer 201 on the substrate 100;

[0054] Step S30 , acid-washing the indium gallium zinc oxide initial layer 201 with an acid wash solution to form an indium gallium zinc oxide thin film 200 .

[0055] In step S10 , the substrate 100 may be a single-layer structure or a multi-layer structure.

[0056] As an example, see Figure 2 The base 100 may include a substrate 110 and an isolation dielectric layer 120 .

[0057] The material of the substrate 110 may be any one of semiconductor material, insulating material, and conductive material. For example, the substrate 110 may include but is not limited to a silicon substrate.

[0058] The isolation dielectric layer 120 may be formed on the surface of the substrate 110. The material of the isolation dielectric layer 120 may include but is not limited to silicon oxide (SiO2), silicon nitride (Si3N4), silicon oxynitride (SiON) or aluminum oxide (Al2O3).

[0059] In step S20, refer to Figure 3 When the base 100 may include a substrate 110 and an isolation dielectric layer 120 , the indium gallium zinc oxide initial layer 201 may be formed on the isolation dielectric layer 120 .

[0060] At this time, after the InGaZnO film 200 is formed in a subsequent step, the isolation dielectric layer 120 can effectively isolate the InGaZnO film 200 from the substrate 110 .

[0061] Of course, in some cases, for example, when the material of the substrate 110 is an insulating material, the base 100 may also include only the substrate 110 without including the isolation dielectric layer 120. In this case, the indium gallium zinc oxide initial layer 201 may be directly formed on the substrate 110.

[0062] Meanwhile, the formation method of the indium gallium zinc oxide initial layer 201 can be a solution method.

[0063] As an example, hydrated indium nitrate [In(NO3)3·xH2O analytical grade], hydrated gallium nitrate [Ga(NO3)3·xH2O analytical grade] and zinc acetate dihydrate [Zn(CH3COO)2·2H2O analytical grade] can be used as indium source, gallium source and zinc source respectively, dissolved in dimethoxyethanol [CH3OCH2CH2OH analytical grade], and a certain amount of ethanolamine [C2H7NO analytical grade] is added as a stabilizer to form a configuration solution with a preset volume and a preset substance concentration. At the same time, the molar ratio of In:Ga:Zn in the configuration solution can be a preset ratio. Among them, the preset volume can be, for example, 10mL, and the preset substance concentration can be, for example, 0.3mol / L. The preset ratio can be, for example, 1:1:2 or 1:1:1.

[0064] Then, the prepared solution may be left to stand for a preset time, so that a uniform, transparent, colorless solution may be obtained after the prepared solution is filtered, thereby forming an indium gallium zinc oxide initial layer 201 on the substrate 100 .

[0065] The solution method is one of the important methods to achieve cheap and low-temperature preparation of large-area IGZO thin films. The solution method has the advantages of low temperature, simple operation, and low cost. However, the IGZO thin films prepared by the solution method are of low quality, with a rough surface and high defect density.

[0066] Of course, the InGaZnO initial layer 201 may also be formed by other methods, for example, it may also be formed by a vapor phase method.

[0067] In step S30, refer to Figure 4 After the indium gallium zinc oxide initial layer 201 is pickled, the surface of the obtained indium gallium zinc oxide thin film 200 can be smoother than the surface of the indium gallium zinc oxide initial layer 201 .

[0068] As an example, the pickling liquid may be a medium-strong acid pickling liquid. The medium-strong acid may include, for example, any one or more of tartaric acid, sulfurous acid, pyruvic acid, oxalic acid, nitrous acid, hydrofluoric acid, and formic acid. The medium-strong acid pickling liquid may be, for example, a medium-strong acid diluted with deionized water, and the ratio of deionized water to acid may be 10:1.

[0069] Of course, the pickling solution may not be a medium-strong acid pickling solution, for example, it may also be a weak acid pickling solution.

[0070] During pickling, the indium gallium zinc oxide initial layer 201 may be pickled for a preset time by using a pickling solution, thereby forming the indium gallium zinc oxide thin film 200. The preset time may be, for example, 10 seconds to 2 minutes.

[0071] After pickling, the formed indium gallium zinc oxide film 200 can be rinsed with deionized water or the like to remove the pickling solution. Then, the indium gallium zinc oxide film 200 can be dried with a preset gas. The preset gas can include but is not limited to an inert gas such as nitrogen.

[0072] When the indium gallium zinc oxide initial layer 201 is pickled, the pickling solution can dissolve oxygen on the surface of the indium gallium zinc oxide initial layer 201, thereby generating oxygen vacancies. Figure 5 As can be seen from the schematic diagram, compared with the area not in contact with the pickling solution, the oxygen vacancy concentration in the area of ​​the indium gallium zinc oxide initial layer 201 in contact with the pickling solution is significantly increased.

[0073] In this embodiment, the surface of the indium gallium zinc oxide film 200 formed after pickling has oxygen vacancies, so that the indium gallium zinc oxide film 200 can form good contact with the electrodes (source and drain) through the oxygen vacancies, thereby effectively reducing the contact resistance. When the pickling solution is a medium-strong acid pickling solution, the amorphous oxides of indium, gallium and zinc do not react with the medium-strong acid, so after being treated with the medium-strong acid, more oxygen vacancies will appear on the surface, which is more conducive to reducing the contact resistance.

[0074] Furthermore, after the initial indium gallium zinc oxide layer 201 is pickled, the surface of the obtained indium gallium zinc oxide film 200 can be smoother, that is, the surface roughness of the indium gallium zinc oxide film 200 can be lower. At this time, the contact resistance can be further reduced.

[0075] At the same time, when the initial InGaZnO layer 201 is pickled, some oxygen vacancies generated on its surface can diffuse inward, thereby obtaining more oxygen vacancies. Therefore, the mobility of the InGaZnO film 200 formed after pickling can also be effectively improved.

[0076] In one embodiment, step S30 includes:

[0077] Step S31 , immersing the indium gallium zinc oxide initial layer 201 in an acid cleaning solution to perform acid cleaning on the indium gallium zinc oxide initial layer 201 .

[0078] At this time, after forming the initial indium gallium zinc oxide layer 201 by solution method or vapor deposition method, the substrate 100 formed with the initial indium gallium zinc oxide layer 201 is immersed in an acid cleaning solution for a preset time, which can be, for example, 10 seconds to 2 minutes.

[0079] In this embodiment, each position of the indium gallium zinc oxide initial layer 201 can be in contact with the pickling solution more evenly, so that the reaction can be carried out more evenly, thereby making the oxygen vacancies more evenly distributed.

[0080] In one embodiment, step S30 includes:

[0081] In step S32 , an acid wash solution is sprayed onto the indium gallium zinc oxide initial layer 201 , and the substrate 100 formed with the indium gallium zinc oxide initial layer 201 is rotated to perform acid wash on the indium gallium zinc oxide initial layer 201 .

[0082] At this time, after forming the initial indium gallium zinc oxide layer 201 by a solution method or a vapor deposition method, the substrate 100 formed with the initial indium gallium zinc oxide layer 201 can be placed on a rotating table and fixed on the rotating table by vacuum adsorption or electrostatic adsorption.

[0083] Then, an acid wash solution is sprayed onto the IGaZnO initial layer 201 through a nozzle on the rotating table, and the rotating table is rotated at the same time, so that the substrate 100 formed with the IGaZnO initial layer 201 rotates with the rotating table, thereby acid washing the IGaZnO initial layer 201 for a preset time.

[0084] In this embodiment, while the pickling solution is sprayed on the InGaZnO initial layer 201 , the InGaZnO initial layer 201 is rotated so that the pickling solution can evenly cover the InGaZnO initial layer 201 , thereby evenly generating oxygen vacancies on the surface of the InGaZnO initial layer 201 .

[0085] At the same time, by continuously spraying the pickling solution and rotating the substrate 100 within a preset time, the reaction byproducts can be taken away in time, and the surface of the indium gallium zinc oxide initial layer 201 can continuously react effectively to generate more oxygen vacancies.

[0086] In one embodiment, the indium gallium zinc oxide initial layer 201 is formed by a vapor deposition method, and in a deposition chamber for forming the indium gallium zinc oxide initial layer 201 , the indium gallium zinc oxide initial layer 201 is in-situ acid-washed.

[0087] Vapor deposition methods include chemical vapor deposition and physical vapor deposition. In-situ pickling means that deposition and pickling are carried out in the same process chamber.

[0088] At this time, in step S20 , when forming the indium gallium zinc oxide initial layer 201 , the substrate 100 may be placed in a deposition chamber first, and then chemical vapor deposition or physical vapor deposition is performed on the substrate 100 to form the indium gallium zinc oxide initial layer 201 .

[0089] Then, in step S32 , in a deposition chamber for forming the InGaZnO initial layer 201 , an acid wash solution may be sprayed on the InGaZnO initial layer 201 , and the substrate 100 formed with the InGaZnO initial layer 201 may be rotated to acid wash the InGaZnO initial layer 201 .

[0090] As an example, when depositing the indium gallium zinc oxide initial layer 201 in a deposition chamber, the substrate 100 can be placed on a pedestal. The pedestal can be a rotatable pedestal. When performing pickling, the pedestal can be used as a turntable, and the substrate 100 formed with the indium gallium zinc oxide initial layer 201 can be rotated by rotating the pedestal.

[0091] As another example, a turntable can also be independently arranged in the deposition chamber. At this time, after the indium gallium zinc oxide initial layer 201 is formed on the substrate 100, the substrate 100 formed with the indium gallium zinc oxide initial layer 201 can be transferred to the turntable by a manipulator.

[0092] In this embodiment, by performing in-situ pickling on the indium gallium zinc oxide initial layer, the contamination of the thin film can be reduced. At the same time, since the process chamber does not need to be switched at this time, the process efficiency can be effectively improved.

[0093] In one embodiment, the indium gallium zinc oxide initial layer 201 includes n initial sub-layers 201a formed in sequence, and the indium gallium zinc oxide thin film 200 includes n thin film sub-layers 200a, where n is a positive integer greater than 1. Among them, each initial sub-layer 201a can correspondingly form a thin film sub-layer 200a.

[0094] Step S20 includes:

[0095] Step S20a, please refer to Figure 6 , forming the i-th initial sub-layer 201a on the (i - 1)-th thin film sub-layer, where i is a positive integer, and k ≤ i ≤ n, 2 ≤ k < n;

[0096] Step S30 includes:

[0097] Step S30a, please refer to Figure 7 , pickling the i-th initial sub-layer 201a with an acid cleaning solution to form the i-th thin film sub-layer 200a.

[0098] In step S20a, i is a positive integer, and k ≤ i ≤ n, 2 ≤ k < n, that is, i can have multiple values, k is the minimum value of i, and k can be 2, or other integers greater than 2 and less than n. For example, when k = 2, i can have multiple values from 2 to n. When k = 3, i can have multiple values from 3 to n.

[0099] The k - 1 thin film sub-layers 200a before the k-th initial sub-layer 201a can be the corresponding thin film sub-layers 200a formed by pickling, or can be the corresponding thin film sub-layers 200a formed directly without pickling.

[0100] In step S30a, after the i-th initial sub-layer 201a is pickled, the formed i-th film sub-layer 200a may be rinsed with deionized water or the like to remove the pickling liquid. Then, the i-th film sub-layer 200a may be dried with a preset gas. The preset gas may include, but is not limited to, an inert gas such as nitrogen.

[0101] Afterwards, the process may return to step S20a to form the (i+1)th initial sub-layer 201a on the dried (i)th film sub-layer 200a (see Figure 7 ), until the nth thin film sub-layer 200a is formed (see Figure 8 ), and after rinsing and drying it, the preparation of the indium gallium zinc oxide film 200 is completed.

[0102] In this embodiment, at least from the kth initial sublayer 201a to the nth initial sublayer 201a, after each initial sublayer 201a is formed, the initial sublayer 201a is pickled to form a corresponding thin film sublayer 200a. Therefore, at least from the kth thin film sublayer 200a to the nth thin film sublayer 200a, oxygen vacancies are formed in each thin film sublayer 200a, and each thin film sublayer 200a has a large mobility, so that the mobility of the indium gallium zinc oxide thin film 200 formed by stacking the thin film sublayers 200a can be effectively improved.

[0103] In one embodiment, step S20 further includes:

[0104] Step S20b, forming the first k-1 initial sub-layers 201a on the substrate, and the first k-1 initial sub-layers that have not been acid-washed form the first k-1 thin film sub-layers 200a.

[0105] At this time, the k-1 thin film sub-layers 200a before the k-th initial sub-layer 201a are directly formed into corresponding thin film sub-layers 200a without being acid washed.

[0106] For example, when k=2, the first film sub-layer 200a is directly formed without acid washing; when k=3, the first and second film sub-layers 200a are directly formed without acid washing.

[0107] It is understandable that when k is greater than 2, each time an initial sublayer 201a is formed, the initial sublayer 201a can be used as a thin film sublayer 200a, and then the next initial sublayer 201a can be directly formed on the surface of the previously formed initial sublayer 201a.

[0108] At this time, by forming the thin film sub-layer 200 a without performing acid washing, leakage between the indium gallium zinc oxide thin film 200 and the substrate 110 can be prevented.

[0109] In one embodiment, the thickness of the first k-1 initial sub-layers 201 is 10 nm-20 nm, and the total thickness of the remaining initial sub-layers is 20 nm-30 nm.

[0110] For example, when k=2, the thickness of the first initial sub-layer 201 is 10 nm-20 nm, and the total thickness of the second to nth initial sub-layers 201 is 20 nm-30 nm.

[0111] For another example, when k=3, the total thickness of the first and second thin film sub-layers 200a is 10nm-20nm, and the total thickness of the third to nth initial sub-layers 201 is 20nm-30nm.

[0112] For the convenience of preparation, k can be set to 2, that is, the thin film sub-layer 200a without acid washing can be prepared at one time, thereby simplifying the process.

[0113] In one embodiment, when the indium gallium zinc oxide initial layer 201 includes n initial sublayers 201a formed sequentially, and the indium gallium zinc oxide film 200 includes n film sublayers 200a, when each initial sublayer 201a is pickled, the acidity and / or concentration of the pickling solution are not completely the same.

[0114] As an example, when pickling the kth to nth initial sub-layers formed sequentially, a medium-strong acid pickling solution with increasing concentrations can be selected to increase the oxygen vacancy concentration of the indium gallium zinc oxide film 200 from bottom to top.

[0115] As another example, when pickling the kth to nth initial sub-layers formed sequentially, a medium-strong acid pickling solution may be selected to pickle the initial sub-layer 201 located in the middle, and a weak acid pickling solution may be selected to pickle the initial sub-layer 201 located in the upper portion. In this case, the oxygen vacancy concentration in the middle of the indium gallium zinc oxide film 200 may be greater than the oxygen vacancy concentration in the upper portion of the indium gallium zinc oxide film 200.

[0116] In this embodiment, the oxygen vacancy concentration of the InGaZnO film 200 can be controlled as required, so that the oxygen vacancy concentrations at different depths of the InGaZnO film 200 are different.

[0117] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1At least part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily performed at the same time, but can be performed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0118] In one embodiment, a method for preparing an indium gallium zinc oxide transistor is also provided, comprising:

[0119] Step S100, providing any one of the above-mentioned indium gallium zinc oxide thin films 200;

[0120] Step S200 , forming an InGaZnO transistor 300 based on the InGaZnO thin film 200 .

[0121] In step S100, the already prepared indium gallium zinc oxide thin film 200 may be directly provided. The indium gallium zinc oxide thin film 200 may also be prepared based on any of the above-mentioned methods for preparing an indium gallium zinc oxide thin film.

[0122] In step S200 , the InGaZnO thin film 200 may be used as a semiconductor active layer, so that an InGaZnO transistor 300 may be formed based on the InGaZnO thin film 200 .

[0123] See also Fig. 9 The source region 301, the drain region 302 and the channel region 303 of the InGaZnO transistor 300 are located in the InGaZnO film 200. The source region 301 and the drain region 302 can be formed by doping the InGaZnO film 200. The channel region 303 can be located between the source region 301 and the channel region 303.

[0124] Meanwhile, the indium gallium zinc oxide transistor 300 may further include a gate dielectric layer 310, a gate 320, and a source 330 and a drain 340 on both sides of the gate 320. The source 330 and the drain 340 are respectively in contact with the source region 301 and the drain region 302 in the indium gallium zinc oxide film 200. The gate dielectric layer 310 is located between the gate 320 and the indium gallium zinc oxide film 200.

[0125] In this embodiment, an indium gallium zinc oxide transistor 300 is formed based on the indium gallium zinc oxide film 200 formed by acid washing, so that a good ohmic contact is formed between the source 330 of the indium gallium zinc oxide transistor 300 and the source region 301 of the indium gallium zinc oxide film 200, and a good ohmic contact is formed between the drain 340 of the indium gallium zinc oxide transistor 300 and the drain region 302 of the indium gallium zinc oxide film 200. At the same time, the carrier mobility in the channel region 303 of the indium gallium zinc oxide transistor 300 can be effectively increased.

[0126] In one embodiment, step S200 includes:

[0127] Step S210, forming a source electrode 330 and a drain electrode 340 on the InGaZnO film 200;

[0128] In step S220 , a gate dielectric layer 310 and a gate 320 are formed on the InGaZnO film 200 between the source 330 and the drain 340 .

[0129] In step S210 , a first electrode material layer may be first formed on the indium gallium zinc oxide thin film 200 . Then, the first electrode material layer may be patterned to form a source electrode 330 and a drain electrode 340 .

[0130] The materials of the source 330 and the drain 340 may include, but are not limited to, metal materials such as cobalt (Co), nickel (Ni), titanium (Ti), tungsten (W), tantalum (Ta), copper (Cu), and aluminum (Al).

[0131] In step S220, a gate dielectric material layer and a second electrode material layer may be formed sequentially on the surface of the indium gallium zinc oxide film 200, the surface of the source 330, and the surface of the drain 340 by a deposition process. Then, the gate dielectric material layer and the second electrode material layer located on the surface of the source 330 and the surface of the drain 340 are sequentially etched and removed, thereby forming a gate dielectric layer 310 and a gate 320.

[0132] The deposition process may include but is not limited to one or more of a chemical vapor deposition process (CVD), an atomic layer deposition process (ALD), a high density plasma deposition (HDP), a plasma enhanced deposition process, and a spin-on dielectric layer (SOD).

[0133] Meanwhile, the gate dielectric layer 310 may be formed of a material having a high-k dielectric constant. For example, the material of the gate dielectric layer includes aluminum oxide (Al2O3), hafnium oxide (HfO2), hafnium oxynitride (HfON), zirconium oxide (ZrO2), tantalum oxide (Ta2O5), titanium oxide (TiO2) or strontium titanium oxide (SrTiO3). Of course, the gate dielectric layer 310 may also be formed of a material having a low-k dielectric constant. For example, the material of the gate dielectric layer 310 includes silicon oxide (SiO2), silicon nitride (Si3N4) or silicon oxynitride layer (SiON), etc.

[0134] The material of the gate 320 may include, but is not limited to, metal materials such as cobalt (Co), nickel (Ni), titanium (Ti), tungsten (W), tantalum (Ta), copper (Cu), and aluminum (Al).

[0135] After forming the gate 320 , the indium gallium zinc oxide film 200 between the gate 320 and the source 330 and between the gate 320 and the drain 340 may be doped, and the doped ions may diffuse under the source 330 and the drain 340 , thereby forming a source region 301 and a drain region 302 .

[0136] In this embodiment, after forming the indium gallium zinc oxide film 200, the source electrode 330 and the drain electrode 340 are formed first, and then the gate dielectric layer 310 and the gate electrode 320 are formed. After forming the indium gallium zinc oxide film 200, the oxygen vacancy concentration on the surface of the indium gallium zinc oxide film 200 is high. At this time, the source electrode 330 and the drain electrode 340 are formed, which can effectively reduce the contact resistance between the source electrode 330 and the indium gallium zinc oxide film 200, and reduce the contact resistance between the drain electrode 340 and the indium gallium zinc oxide film 200.

[0137] Of course, in other embodiments, the method for forming the InGaZnO transistor 300 may be different from this. For example, in step S200, it may also include:

[0138] Step S210a, forming a gate dielectric layer 310 and a gate 320 on the InGaZnO film 200;

[0139] Step S220a, doping the indium gallium zinc oxide film 200 on both sides of the gate 320 to form a source region 301 and a drain region 302;

[0140] In step S230 a , a source electrode 310 and a drain electrode 320 are formed on the source region 301 and the drain region 302 , respectively.

[0141] In step S210a, a gate dielectric material layer and a second electrode material layer may be formed sequentially on the surface of the indium gallium zinc oxide film 200 by a deposition process. Then, the gate dielectric material layer and the second electrode material layer located on the surface of the source 330 and the surface of the drain 340 are sequentially etched away to form a gate dielectric layer 310 and a gate 320.

[0142] In step S220 a , the indium gallium zinc oxide film 200 on both sides of the gate 320 may be doped by ion implantation or the like, thereby forming a source region 301 and a drain region 302 .

[0143] In step S230a, a first electrode material layer may be formed on the surface of the source region 301 and the drain region 302, the gate 320 and the gate dielectric layer 310. Then, the first electrode material layer is patterned to form a source electrode 330 and a drain electrode 340.

[0144] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features of the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0145] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for preparing an indium gallium zinc oxide thin film, characterized in that: include: providing a substrate; forming an initial indium gallium zinc oxide layer on the substrate; The indium gallium zinc oxide initial layer is pickled with an acid pickling solution to form the indium gallium zinc oxide thin film.

2. The method for preparing an indium gallium zinc oxide thin film according to claim 1, characterized in that: The step of pickling the initial indium gallium zinc oxide layer with a pickling solution to form the indium gallium zinc oxide film comprises: The indium gallium zinc oxide initial layer is immersed in the acid cleaning solution to perform acid cleaning on the indium gallium zinc oxide initial layer.

3. The method for preparing an indium gallium zinc oxide thin film according to claim 2, characterized in that: The indium gallium zinc oxide initial layer is formed by a solution method or a vapor phase deposition method.

4. The method for preparing an indium gallium zinc oxide thin film according to claim 1, characterized in that: The step of pickling the initial indium gallium zinc oxide layer with a pickling solution to form the indium gallium zinc oxide film comprises: A pickling solution is sprayed onto the indium gallium zinc oxide initial layer, and the substrate on which the indium gallium zinc oxide initial layer is formed is rotated to pickle the indium gallium zinc oxide initial layer.

5. The method for preparing an indium gallium zinc oxide thin film according to claim 4, characterized in that: The indium gallium zinc oxide initial layer is formed by a vapor deposition method, and in a deposition chamber where the indium gallium zinc oxide initial layer is formed, the indium gallium zinc oxide initial layer is in-situ acid-washed.

6. The method for preparing an indium gallium zinc oxide thin film according to claim 1, characterized in that: The indium gallium zinc oxide initial layer includes n initial sublayers formed sequentially, and the indium gallium zinc oxide thin film includes n thin film sublayers, where n is a positive integer greater than 1. The step of forming an initial indium gallium zinc oxide layer on the substrate comprises: The i-th initial sublayer is formed on the i-1-th thin film sublayer, where i is a positive integer, and k≤i≤n, 2≤k <n; The indium gallium zinc oxide initial layer is pickled with a pickling solution to form the indium gallium zinc oxide thin film, comprising: The i-th initial sub-layer is pickled with a pickling solution to form an i-th thin film sub-layer.

7. The method for preparing an indium gallium zinc oxide thin film according to claim 6, characterized in that: Forming an initial indium gallium zinc oxide layer on the substrate, further comprising: The first k-1 initial sub-layers are formed on the substrate, and the first k-1 initial sub-layers that are not acid-washed form the first k-1 thin film sub-layers.

8. The method for preparing an indium gallium zinc oxide thin film according to claim 7, characterized in that: The thickness of the first k-1 initial sub-layers is 10nm-20nm, and the total thickness of the remaining initial sub-layers is 20nm-30nm.

9. The method for preparing an indium gallium zinc oxide thin film according to claim 6 or 7, characterized in that: When pickling each of the initial sub-layers, the acidity and / or concentration of the pickling solution are not completely the same.

10. The method for preparing an indium gallium zinc oxide thin film according to claim 1, characterized in that: The pickling solution is a medium-strong acid pickling solution.

11. The method for preparing an indium gallium zinc oxide thin film according to claim 10, characterized in that: The medium-strong acid includes any one or more of tartaric acid, sulfurous acid, pyruvic acid, oxalic acid, nitrous acid, hydrofluoric acid and formic acid.

12. The method for preparing an indium gallium zinc oxide thin film according to claim 10, characterized in that: The medium-strong acid pickling solution is a medium-strong acid diluted with deionized water, and the ratio of deionized water to acid is 10:1, and the pickling time is 10s-2min.

13. The method for preparing an indium gallium zinc oxide thin film according to claim 1, characterized in that: The base comprises a substrate and an isolation dielectric layer, and the forming of an indium gallium zinc oxide initial layer on the base comprises: The indium gallium zinc oxide initial layer is formed on the isolation dielectric layer.

14. A method for preparing an indium gallium zinc oxide transistor, characterized in that: include: Providing the indium gallium zinc oxide thin film according to any one of claims 1 to 13; The indium gallium zinc oxide transistor is formed based on the indium gallium zinc oxide thin film.

15. The method for preparing an indium gallium zinc oxide transistor according to claim 14, characterized in that: The method of forming the indium gallium zinc oxide transistor based on the indium gallium zinc oxide thin film comprises: forming a source electrode and a drain electrode on the indium gallium zinc oxide thin film; A gate dielectric layer and a gate are formed on the indium gallium zinc oxide film between the source and the drain.

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