Thin film transistor and preparation method thereof, display panel

Abstract

The application discloses a thin film transistor and a preparation method thereof and a display panel. The thin film transistor comprises a substrate, an active layer arranged on one side of the substrate, and a source-drain electrode layer arranged on a side of the active layer opposite to the substrate, and the active layer and the source-drain electrode layer are in ohmic contact. The material of the source-drain electrode layer is lanthanum boride, and the material of the active layer comprises lanthanum boride. In the application, the material of the source-drain electrode layer is lanthanum boride, and the material of the active layer comprises lanthanum boride, so that after the active layer is formed, the source-drain electrode layer can continue to be formed through the same film forming process as the active layer, realizing one-time continuous film forming of the film layers of the active layer and the source-drain electrode layer, thereby helping to simplify the process of the film forming process and greatly improving the productivity of the film forming process. In addition, the element types of the materials of the active layer and the source-drain electrode layer are consistent, which helps to reduce the interface energy barrier between the active layer and the source-drain electrode layer, so that the ohmic contact of the two is perfect, thereby effectively avoiding the generation of interface defects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display devices, in particular to a thin film transistor, a preparation method thereof and a display panel. BACKGROUND

[0002] At present, thin film transistor (TFT) display panels are widely used in various display devices and have the characteristics of high response, high brightness and high contrast. The manufacturing of TFT display panels can be roughly divided into TFT array process, liquid crystal cell process and liquid crystal module process. Among them, the TFT array process has an important influence on the display performance of the display panel, and has a particularly prominent influence on the preparation cost of the display panel. When the process of the TFT array process is complicated and the operation is complex, the equipment productivity and utilization rate are easily reduced, and the preparation efficiency of the TFT display panel is affected. SUMMARY

[0003] Embodiments of the present application provide a thin film transistor, a preparation method thereof and a display panel, which are helpful to improve the productivity of the thin film transistor.

[0004] Embodiments of the present application provide a thin film transistor, which comprises a substrate, an active layer arranged on one side of the substrate, and a source-drain layer arranged on the side of the active layer opposite to the substrate, and the active layer and the source-drain layer are ohmic contact.

[0005] The material of the source-drain layer is lanthanum boride, and the material of the active layer comprises lanthanum boride.

[0006] According to an embodiment of the present application, the material of the active layer is first lanthanum boride, and the material of the source-drain layer is second lanthanum boride, the boron content of the first lanthanum boride is greater than the boron content of the second lanthanum boride, so that the first lanthanum boride exhibits semiconductor properties and the second lanthanum boride exhibits conductor properties.

[0007] According to an embodiment of the present application, the chemical formula of the first lanthanum boride is La x1 B y1 , wherein when y1=1, x1 is not less than 0.05 and not greater than 0.17; and / or,

[0008] The chemical formula of the second lanthanum boride is La x2 B y2 , wherein when y2=1, x2 is not less than 0.17 and not greater than 1.

[0009] According to an embodiment of the present application, the material of the source-drain electrode is third lanthanum boride exhibiting conductor characteristics, and the material of the active layer is an oxide semiconductor doped with the third lanthanum boride.

[0010] According to an embodiment of the present application, the thin film transistor further comprises a gate metal layer and a gate insulating layer between the substrate and the active layer, the gate metal layer is convex on one side of the substrate, the gate insulating layer covers the side of the gate metal layer and the side opposite to the substrate, and the active layer is arranged on the side of the gate insulating layer opposite to the substrate.

[0011] To achieve the above-mentioned purpose, the present application further provides a preparation method for preparing the thin film transistor as described above, comprising:

[0012] providing a substrate, and sequentially forming two lanthanum boride film layers on the substrate by the same film forming process;

[0013] forming an active layer on the lanthanum boride film layer close to the substrate and forming a source-drain electrode layer on the remaining lanthanum boride film layer by a patterning process.

[0014] According to an embodiment of the present application, the step of sequentially forming two lanthanum boride film layers on the substrate by the same film forming process comprises:

[0015] obtaining first lanthanum boride exhibiting semiconductor characteristics and second lanthanum boride exhibiting conductor characteristics;

[0016] depositing the first lanthanum boride as target material on the substrate to form a first lanthanum boride film layer, and then depositing the second lanthanum boride as target material on the first lanthanum boride film layer to form a second lanthanum boride film layer by the same physical vapor deposition process.

[0017] According to an embodiment of the present application, the step of forming an active layer on the lanthanum boride film layer close to the substrate and forming a source-drain electrode layer on the remaining lanthanum boride film layer by a patterning process comprises:

[0018] forming a first photoresist by a half-tone mask process, by setting a photoresist on the second lanthanum boride film layer at a set region corresponding to the active layer, and thinning the thickness of the photoresist at a channel region corresponding to the active layer.

[0019] etching and removing the parts of the two lanthanum boride film layers not covered by the photoresist, to form an active layer on the first lanthanum boride film layer;

[0020] removing the first photoresist by a dry ashing process, and obtaining the remaining photoresist as a second photoresist;

[0021] The portion of the second lanthanum boride film layer not blocked by the second photoresist is etched away to form the source and drain layers.

[0022] According to one embodiment of this application, after the step of providing a substrate and before the step of sequentially forming two lanthanum boride films on the substrate using the same film-forming process, the method further includes:

[0023] A gate metal layer is formed on the substrate by sequentially performing physical vapor deposition, patterning, and wet etching processes.

[0024] A gate insulating layer is deposited on the surface of the gate metal layer using a chemical vapor deposition process.

[0025] To achieve the above objectives, this application provides a display panel, the display panel including thin-film transistors, the thin-film transistors being fabricated using the thin-film transistor fabrication method described above.

[0026] The beneficial effects of the embodiments of this application are as follows: The source and drain electrode layers in this application are made of lanthanum boride, and the active layer is also made of lanthanum boride. This allows the source and drain electrode layers to be deposited using the same deposition process as the active layer after the active layer is deposited, thus achieving continuous deposition of the active layer and the source and drain electrode layers in one continuous process. This simplifies the deposition process and greatly improves the production capacity of the deposition process. In addition, the active layer and the source and drain electrode layers in this application are made of the same element type, which helps to reduce the boundary energy barrier between the active layer and the source and drain electrode layers, making the ohmic contact between the two perfect and effectively avoiding the generation of interface defects. Attached Figure Description

[0027] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the structure of a thin-film transistor provided in an embodiment of this application.

[0029] Figure 2 A schematic flowchart illustrating the fabrication method of a thin-film transistor provided in an embodiment of this application;

[0030] Figure 3 for Figure 1 A schematic diagram of the thin-film transistor in step S111;

[0031] Figure 4 for Figure 1 A schematic diagram of the thin-film transistor in step S112;

[0032] Figure 5 for Figure 1 A schematic diagram of the thin-film transistor in steps S121-S122;

[0033] Figure 6 for Figure 1 A schematic diagram of the thin-film transistor in step S210;

[0034] Figure 7 for Figure 1 A schematic diagram of the thin-film transistor in step S220;

[0035] Figure 8 for Figure 1 A schematic diagram of the thin-film transistor in step S230;

[0036] Figure 9 for Figure 1 A schematic diagram of the thin-film transistor in step S240. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0038] Please see Figure 1 This application provides a thin-film transistor 1 used in a display panel. In this application, the thin-film transistor 1 includes a substrate 110, an active layer 210 disposed on one side of the substrate 110, and a source / drain layer 310 disposed on one side of the active layer 210. The active layer 210 and the source / drain layer 310 are ohmic contacts. The source / drain layer 310 is made of lanthanum boride, and the active layer 210 is also made of lanthanum boride.

[0039] The beneficial effects of the embodiments of this application are as follows: The source / drain layer 310 in this application is made of lanthanum boride, and the active layer 210 is also made of lanthanum boride. This allows the source / drain layer 310 to continue to be formed after the active layer 210 is formed, using the same film-forming process as the active layer 210. This enables continuous film formation of the active layer 210 and the source / drain layer 310 in one continuous process, thereby simplifying the film-forming process and greatly improving the production capacity. In addition, the active layer 210 and the source / drain layer 310 in this application are made of the same element type, which helps to reduce the boundary energy barrier between the active layer 210 and the source / drain layer 310, resulting in perfect ohmic contact between the two and effectively avoiding interface defects.

[0040] It can be understood that the substrate 110 in the present application can be directly a transparent plate body, or a plate body on which a required film layer is deposited by various methods. In the present embodiment, the substrate 110 can be provided with a gate metal layer 120 and a gate insulating layer 130. The substrate 110 is a transparent plate body, which can be specifically provided as a rigid plate body or a flexible plate body according to actual process requirements. The rigid plate body can include a glass plate and the like, and the flexible plate body can include a polyimide (PI) film, an ultra-thin glass film and the like. The display panel made of the flexible plate body has the characteristics of being bendable and the like.

[0041] One side of the substrate 110 is formed with the gate metal layer 120 through film formation, patterning, exposure, etching and the like. The specific manner of each process is not limited, which can be selected and applied according to actual needs. The material of the gate metal layer 120 is not limited, which can be selected from one or more of Mo, Al, Ti, Cu and the like according to actual needs. Of course, the material of the gate metal layer 120 can also be lanthanum boride.

[0042] The gate metal layer 120 is generally provided protruding on the substrate 110, and the gate insulating layer 130 is continuously deposited on the surface of the gate metal layer 120 exposed from the substrate 110. The surface of the gate metal layer 120 exposed from the substrate 110 is all surfaces exposed except the connecting surface with the substrate 110, including the side surface opposite to the substrate 110 and the circumferential surface extending along the circumferential direction of the gate metal layer 120. The gate metal layer 120 is completely covered by the gate insulating layer 130, which is helpful for good insulation of the gate metal layer 120.

[0043] The active layer 210 is at least located on the side of the gate insulating layer 130 opposite to the substrate 110. It can be understood that when the active layer 210 is prepared on the substrate 110, the projection area of the active layer 210 on the substrate 110 defines a set region 211 of the active layer 210, and the projection area of the channel of the active layer 210 on the substrate 110 defines a channel region 212 of the active layer 210.

[0044] The source-drain layer 310 is located on the side of the active layer 210 opposite to the substrate 110, and specifically includes the source layer 311 and the drain layer 312 oppositely arranged on both sides of the channel region 212, which can be specifically referred to the prior art and will not be described in detail here.

[0045] In order to realize the driving function of the thin film transistor 1 in practical application, the material of the source-drain layer 310 needs to have conductor characteristics, that is, to make the source-drain layer 310 have conductive performance; and the material of the active layer 210 needs to have semiconductor characteristics, that is, to make the conductive performance of the active layer 210 be between conductor and insulator at normal temperature. Research shows that the chemical formula of lanthanum boride is La x B y By adjusting the specific values of x and y in the chemical formula of lanthanum boride, the conversion of lanthanum boride between conductor and semiconductor can be realized. Moreover, the higher the content of boron element in lanthanum boride is, the lower the concentration and conductivity of the carrier will be, which is more conducive to the conversion of lanthanum boride from conductor to semiconductor.

[0046] In view of the above, the lanthanum boride used to prepare the source-drain layer 310 in the present application is set to exhibit conductor characteristics, while the lanthanum boride used to prepare the active layer 210 is not limited:

[0047] In specific applications, the semiconductor characteristics of the active layer 210 can be directly embodied by the lanthanum boride material: in an embodiment, the material of the active layer 210 is defined as first lanthanum boride, and the material of the source-drain layer 310 is defined as second lanthanum boride, that is, the main material of the active layer 210 is only the first lanthanum boride, and the semiconductor characteristics of the active layer 210 are directly embodied by the first lanthanum boride. Specifically, by adjusting the boron content of the first lanthanum boride and the boron content of the second lanthanum boride, at least when the boron content of the first lanthanum boride is greater than that of the second lanthanum boride, the first lanthanum boride can exhibit semiconductor characteristics and the second lanthanum boride can exhibit conductor characteristics. In this way, since the chemical elements of the first lanthanum boride and the second lanthanum boride are both boron and lanthanum, the difference mainly lies in the content of boron, which makes it possible to realize the semiconductor characteristics of the active layer 210 and the conductor characteristics of the source-drain layer 310 without adding other materials, and the active layer 210 and the source-drain layer 310 can be continuously formed at one time as described above. After forming, the active layer 210 and the source-drain layer 310 have the characteristics of perfect ohmic contact as described above, which is helpful for the material simplification and process simplification of the TFT thin film transistor 1 in the preparation process, and greatly improves the production capacity.

[0048] Of course, the present application does not limit the specific element ratio of the first lanthanum boride and the second lanthanum boride which can meet the above requirements. Specifically, in an embodiment, when the chemical formula of the first lanthanum boride is defined as La x1 B y1 , and y1=1, x1 can be specifically set to be not less than 0.05 and not greater than 0.17, and within this range, the first lanthanum boride exhibits semiconductor characteristics and can be used to prepare the active layer 210; and / or when the chemical formula of the second lanthanum boride is defined as Lax2 B y2 , and when y2 = 1, x2 can be set to be not less than 0.17 and not more than 1, within this range, the second lanthanum boride exhibits conductor characteristics, which can be applied to the preparation of the source-drain layer 310.

[0049] It should be noted that the above embodiments do not constitute the lanthanum boride LaB6 x B y The value of y in the above embodiments is limited, that is, in actual application, y can be 1, and can also be set to other values, as long as the above functions are met, and the embodiments of the present application will not be described here.

[0050] In addition, in specific applications, the semiconductor characteristics of the active layer 210 can also be exhibited by other semiconductor materials, that is, the material of the active layer 210 includes lanthanum boride and other semiconductor materials, by doping lanthanum boride into the semiconductor material, the characteristics of the semiconductor material can be enhanced: in an embodiment, when the material of the source-drain electrode is a third lanthanum boride, the third lanthanum boride exhibits conductor characteristics, and the material of the active layer 210 is an oxide semiconductor doped with the third lanthanum boride. Specifically, the third lanthanum boride can be lanthanum hexaboride LaB6, and the oxide semiconductor can be a zinc oxide-based material, and the chemical formula of the zinc oxide-based material is (MO) i (In2O3) j (ZnO) 1-i-j , wherein 0≤i≤0.2, 0≤j≤0.8; MO is one of Ga2O3, Al2O3, Ta2O5. The mass ratio of the third lanthanum boride to the zinc oxide-based material is not less than 0.005 and not more than 0.1.

[0051] By doping the third lanthanum boride LaB6 into the zinc oxide-based material, the electron mobility of the doped oxide semiconductor is improved due to the n-type electron transport characteristics of LaB6; and because the electronegativity of lanthanum element is very weak, the attraction of lanthanum element to oxygen in the zinc oxide-based material is strong, which helps to reduce oxygen vacancies, reduce off-state current and improve the on-off ratio. That is, the third lanthanum boride LaB6 can enhance the semiconductor characteristics of the oxide semiconductor.

[0052] It should be noted that when the active layer 210 is a multi-film layer structure including the third lanthanum boride and the oxide semiconductor, the film layer formed by the third lanthanum boride can be located at any position in the remaining other film layers, for example, the film layer formed by the third lanthanum boride can be located on the film layer closest to the source-drain layer 310, which helps the continuous film formation of the film layer of the third lanthanum boride and the source-drain layer 310.

[0053] In view of any of the above embodiments, the present application does not specifically limit the specific preparation process of each film layer of the thin film transistor 1, but optionally, please refer to Figure 2 The present application also provides a preparation method for preparing the thin film transistor 1 as described above, specifically comprising the following steps:

[0054] Step S100: providing a substrate 110, and forming two lanthanum boride film layers on the substrate 110 in sequence by the same film forming process;

[0055] In the present embodiment, the substrate 110 can be a substrate after the required film layers such as the metal gate layer and the metal insulating layer are prepared as described above. The specific preparation method of the metal gate layer and the metal insulating layer is not limited, and can be specifically:

[0056] In the step S100, after the step of "providing a substrate 110", and before the step of "forming two lanthanum boride film layers on the substrate 110 in sequence by the same film forming process", it specifically further comprises:

[0057] Step S111: sequentially forming a gate metal layer 120 on the substrate 110 by a physical vapor deposition process, a patterning process and a wet etching process;

[0058] In the present embodiment, please refer to Figure 3 The substrate 110 can be a flexible plate body or a rigid plate body as described above. In specific applications, the required material can be first vaporized into gaseous atoms, gaseous molecules or partially ionized into ions from the target surface by a physical vapor deposition (PVD) process, and then deposited on the substrate 110 by a low-pressure gas or plasma process, to form a first metal film layer. The first metal film layer can be a film layer covering the entire surface of the substrate 110 after the PVD process. Based on this, a required pattern needs to be formed on the first metal film layer by a patterning process, for example, covering photoresist on the first metal film layer, and performing hole opening operation at the required position of the photoresist; then the unshielded part of the first metal film layer is etched by a wet etching process, and after removing the remaining photoresist, a gate metal layer 120 is finally obtained on the surface of the substrate 110.

[0059] Step S112: depositing a gate insulating layer 130 on the surface of the gate metal layer 120 by a chemical vapor deposition process.

[0060] In the present embodiment, please refer to Figure 4After the substrate 110 and the gate metal layer 120 are obtained, a chemical vapor deposition (CVD) process is then performed to form a gate insulating layer 130 on the surface of the substrate 110 and the gate metal layer 120 by chemical reaction of one or more gas phase compounds or elements containing the required elements. The gate insulating layer 130 covers at least the surface of the gate metal layer 120, and can further extend to cover the part of the substrate 110 where no gate insulating layer 130 is provided, if necessary.

[0061] According to the above steps, the substrate 110 provided with the gate metal layer 120 and the gate insulating layer 130 is obtained.

[0062] In addition, when the lanthanum boride (i.e. the first lanthanum boride mentioned above) used to prepare the active layer 210 and the lanthanum boride (i.e. the second lanthanum boride mentioned above) used to prepare the source-drain layer 310 are two lanthanum boride materials with the same element but different boron contents, in an embodiment, the step of "forming two lanthanum boride film layers on the substrate 110 in sequence by the same film forming process" in the step S100 can specifically include:

[0063] Step S121: obtaining a first lanthanum boride exhibiting semiconductor properties and a second lanthanum boride exhibiting conductor properties;

[0064] Step S122: depositing the first lanthanum boride as a target material on the substrate 110 to form a first lanthanum boride film layer 200, and then depositing the second lanthanum boride as a target material on the first lanthanum boride film layer 200 to form a second lanthanum boride film layer 300 by the same physical vapor deposition process.

[0065] In this embodiment, please refer to Figure 5Using the same film-forming process, specifically physical vapor deposition (PVD) as described above, the first lanthanum boride is first used as the target material for the first film-forming process. By setting process parameters, the first lanthanum boride is deposited and covers the side of the gate insulating layer 130 facing away from the substrate 110, forming the first lanthanum boride film layer 200. Then, the second lanthanum boride is used as the target material for the second film-forming process. Continuing with the previously set process parameters, or after adapting the process parameters, the first lanthanum boride is deposited and covers the side of the first lanthanum boride film layer 200 facing away from the substrate 110, forming the second lanthanum boride film layer 300. The deposition thickness and shape of the first lanthanum boride film layer 200 and the second lanthanum boride film layer 300 can be adjusted according to actual conditions. As can be seen from the above, the first lanthanum boride film layer 200 is a lanthanum boride film layer with relatively high boron content, exhibiting semiconductor characteristics; the second lanthanum boride film layer 300 is a lanthanum boride film layer with relatively low boron content, exhibiting conductor characteristics. Both lanthanum boride films formed by the PVD process are transparent, which helps to improve the light transmittance of thin-film transistor 1.

[0066] Of course, when the lanthanum boride used to prepare the active layer 210 and the lanthanum boride used to prepare the source / drain layer 310 are the same lanthanum boride material with the same elemental composition and boron content (i.e., the third lanthanum boride mentioned above), in another embodiment, the step of "sequentially forming two lanthanum boride films on the substrate 110 using the same film-forming process" in step S100 may specifically include:

[0067] Four materials—LaB6 (third lanthanum boride), MO, In2O3, and ZnO—are sputtered simultaneously as four targets to deposit a lanthanum boride film for the active layer 210 on the substrate 110. Then, the target material LaB6 (third lanthanum boride) is retained, and LaB6 (third lanthanum boride) is deposited on the substrate 110 using the same film deposition process to obtain a lanthanum boride film for the source and drain layers 310.

[0068] Step S200: Using a patterning process, an active layer 210 is formed by etching on the lanthanum boron film layer near the substrate 110, and a source / drain layer 310 is formed by etching on the remaining lanthanum boron film layer.

[0069] In this embodiment, after two lanthanum boride films are formed continuously in one film-forming process, the active layer 210’s designated region 211 and channel region 212 can be obtained by etching on the lanthanum boride film near the substrate 110 through a patterning process, and the source and drain layers 310 can be obtained by etching on the lanthanum boride film away from the substrate 110.

[0070] The preparation of the active layer 210 and the preparation of the source-drain layer 310 can be performed independently, for example, two photoresist structures are formed by two masks, and then two etching processes are performed. However, in order to simplify the process, please refer to Figures 6 to 9 In the embodiment, the step S200 specifically includes:

[0071] Step S210: By a half-tone mask process, the photoresist 400 is disposed on the second lanthanum boride film layer 300 at the set region 211 corresponding to the active layer 210, and the thickness of the photoresist 400 at the channel region 212 of the active layer 210 is thinned to form the first photoresist 410.

[0072] In the embodiment, please refer to Figure 6 By a half-tone mask process (HTM), the photoresist 400 is disposed on the second lanthanum boride film layer 300, and the orthographic projection region of the photoresist 400 on the first lanthanum boride film layer 200 is coincided with and has substantially the same boundary as the set region 211 of the active layer 210 to be prepared; the middle part of the photoresist 400 constitutes the first photoresist 410, and the orthographic projection region of the first photoresist 410 on the first lanthanum boride film layer 200 is coincided with and has substantially the same boundary as the channel region 212 of the active layer 210 to be prepared. The remaining part of the photoresist 400 except the first photoresist 410 constitutes the second photoresist 420. Since the first photoresist 410 is subjected to thinning treatment, the thickness of the first photoresist 410 is smaller than the thickness of the second photoresist 420. The specific way of the thinning treatment is, for example, a groove is opened at the corresponding part of the side of the photoresist 400 away from the second lanthanum boride film layer 300, and the groove is not through the photoresist 400, so that a sufficient thickness is reserved between the groove bottom and the bottom of the photoresist 400 (i.e. the side close to the second lanthanum boride film layer 300), which constitutes the first photoresist 410.

[0073] Step S220: Etching to remove the parts of the two lanthanum boride film layers not covered by the photoresist 400, so as to form the active layer 210 on the first lanthanum boride film layer 200.

[0074] In the embodiment, please refer to Figure 7 Since the area of the first lanthanum boride film layer 200 formed after the film forming process is generally larger than the area of the set region 211 of the active layer 210 to be prepared, and the area of the second lanthanum boride film layer 300 is generally larger than the area of the source-drain layer 310 to be prepared and generally smaller than the area of the set region 211, under the action of the photoresist 400, the parts of the first lanthanum boride film layer 200 and the second lanthanum boride film layer 300 not covered by the photoresist 400 can be dissolved and removed by a dissolving agent such as oxalic acid (for reference Figure 7The active layer 210 is formed on the first lanthanum boride film layer 200.

[0075] Step S230: the first photoresist 410 is removed by a dry ashing process, and the remaining photoresist 400 is obtained as a second photoresist 420.

[0076] In the embodiment, referring to Figure 8 The photoresist 400 is thinned in the direction away from the second lanthanum boride film layer 300 by the dry ashing process, so that the structure between the bottom of the groove and the bottom of the photoresist 400 is eliminated, and only the second photoresist 420 is left after the first photoresist 410 is removed.

[0077] Step S240: etching is performed to remove the part of the second lanthanum boride film layer 300 that is not covered by the second photoresist 420, so as to form a source-drain layer 310.

[0078] In the embodiment, referring to Figure 9 The part of the second lanthanum boride film layer 300 that is not covered by the second photoresist 420 is dissolved and removed by a dissolving agent such as oxalic acid, so that the channel region 212 of the first lanthanum boride film layer 200 (i.e. the active layer 210) is exposed, and the second lanthanum boride film layer 300 is divided into a source layer 311 and a drain layer 312, and the preparation of the source-drain layer 310 is completed.

[0079] In addition, the application further provides a display panel, which comprises the thin film transistor 1 as described above. It should be noted that the detailed structure of the thin film transistor 1 in the display panel can refer to the embodiments of the thin film transistor 1 described above, which will not be described here again. Since the thin film transistor 1 described above is used in the display panel of the application, the embodiments of the display panel of the application include all the technical solutions of all the embodiments of the thin film transistor 1 described above, and the technical effects achieved are also completely the same, which will not be described here again. The display panel can be applied to panel designs such as TFT-LCD, TFT-OLED, etc.

[0080] Further, the thin film transistor 1 in the display panel can be prepared by using the preparation method of the thin film transistor 1 as described above.

[0081] Of course, the present application can also provide a display device, which can be a liquid crystal display, a liquid crystal television, a mobile phone, a tablet computer, or the like electrical product or component. The display device includes the display panel as described above. Similarly, the detailed structure of the display panel in the display device can refer to the above-mentioned embodiments of the display panel, which will not be described here; since the above-mentioned display panel is used in the display device of the present application, the embodiments of the display device of the present application include all the technical solutions of all the embodiments of the above-mentioned display panel, and the technical effects achieved are also completely the same, which will not be described here.

[0082] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0083] The thin film transistor and the preparation method thereof, and the display panel provided by the embodiments of the present application are described in detail above, and the principles and implementation manners of the present application are described by applying specific examples; the above description of the embodiments is only used to help understand the technical solutions of the present application and the core ideas thereof; those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A thin-film transistor, characterized in that, It includes a substrate, an active layer disposed on one side of the substrate, and a source / drain layer disposed on the side of the active layer opposite to the substrate, wherein the active layer and the source / drain layer are ohmic contacted. The source and drain layers are made of lanthanum boride, and the active layer is made of lanthanum boride and semiconductor materials. The source and drain layers exhibit conductor properties, and the active layer exhibits semiconductor properties. The active layer, which consists of a lanthanum boride film, is located near the source and drain layers.

2. The thin-film transistor as claimed in claim 1, characterized in that, The active layer is made of first lanthanum boride, and the source / drain layer is made of second lanthanum boride. The boron content of the first lanthanum boride is greater than that of the second lanthanum boride, so that the first lanthanum boride exhibits semiconductor properties and the second lanthanum boride exhibits conductor properties.

3. The thin-film transistor as described in claim 2, characterized in that, The first lanthanum boride has the chemical formula La. x1 B y1 Where, when y1=1, x1 is not less than 0.05 and not greater than 0.17; and / or, The chemical formula of the second lanthanum boride is La. x2 B y2 When y2=1, x2 is not less than 0.17 and not greater than 1.

4. The thin-film transistor as claimed in claim 1, characterized in that, The source and drain layers are made of lanthanum boride third, which exhibits conductive properties, and the active layer is made of an oxide semiconductor doped with lanthanum boride third.

5. The thin-film transistor as claimed in claim 1, characterized in that, The thin-film transistor further includes a gate metal layer and a gate insulating layer located between the substrate and the active layer. The gate metal layer protrudes from one side of the substrate, and the gate insulating layer covers the periphery of the gate metal layer and the side facing away from the substrate. The active layer is located on the side of the gate insulating layer facing away from the substrate.

6. A method for fabricating a thin-film transistor as described in any one of claims 1 to 5, characterized in that, include: A substrate is provided, and two lanthanum boride films are sequentially formed on the substrate using the same film deposition process; An active layer is formed by etching on the lanthanum boride film layer near the substrate, and a source / drain layer is formed by etching on the remaining lanthanum boride film layer.

7. The method for fabricating a thin-film transistor as described in claim 6, characterized in that, The steps of sequentially forming two lanthanum boride films on the substrate using the same film deposition process include: To obtain a first lanthanum boride exhibiting semiconductor properties and a second lanthanum boride exhibiting conductor properties; Using the same physical vapor deposition process, the first lanthanum boride is first deposited on the substrate as a target to form a first lanthanum boride film, and then the second lanthanum boride is deposited on the first lanthanum boride film as a target to form a second lanthanum boride film.

8. The method for fabricating a thin-film transistor as described in claim 7, characterized in that, The steps of etching an active layer on the lanthanum boride film layer near the substrate and etching a source / drain layer on the remaining lanthanum boride film layer using a patterning process include: Using a halftone photomask process, a photoresist is set in a designated area corresponding to the active layer on the second lanthanum boride film layer, and the thickness of the photoresist in the channel region of the active layer is reduced to form a first photoresist. Etching removes two portions of the lanthanum boride film that are not blocked by the photoresist to form an active layer on the first lanthanum boride film; The first photoresist is removed by a dry ashing process, and the remaining photoresist is used as the second photoresist. The portion of the second lanthanum boride film layer not blocked by the second photoresist is etched away to form the source and drain layers.

9. The method for fabricating a thin-film transistor as described in claim 6, characterized in that, After the step of providing a substrate, and before the step of sequentially forming two lanthanum boride films on the substrate using the same film-forming process, the method further includes: A gate metal layer is formed on the substrate by sequentially performing physical vapor deposition, patterning, and wet etching processes. A gate insulating layer is deposited on the surface of the gate metal layer using a chemical vapor deposition process.

10. A display panel, characterized in that, Includes a thin-film transistor, which is fabricated using the method for fabricating a thin-film transistor as described in any one of claims 6 to 9.

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