Semiconductor structure with flexible thin film transistor and preparation method thereof

Abstract

The invention relates to the technical field of semiconductors, in particular to a semiconductor structure with a flexible thin film transistor and a preparation method of the semiconductor structure. The flexible thin film transistor based on the fluorophlogopite substrate is directly transferred to a substrate and bonded with the substrate to form a semiconductor structure, and the problem that the process and equipment of a COMS production line are not suitable for directly forming a Bi2O2Se thin film on the fluorophlogopite substrate and correspondingly preparing a product is solved. Meanwhile, by arranging the thin fluorophlogopite substrate, the flexible thin film transistor can be better transferred and bonded, and meanwhile, the thin fluorophlogopite substrate is crucial to preparation of a complex and multi-layer semiconductor structure. Meanwhile, the thin fluorophlogopite substrate is arranged, so that thermal resistance can be reduced, heat can be transmitted to an external heat dissipation system more quickly, and the overheating risk of the semiconductor structure is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor structure with a flexible thin film transistor and a preparation method thereof. Background Art

[0002] As an important member of the field effect transistor family, flexible TFT (thin film transistor) has been widely used in many fields in recent years. It has become the mainstream technology for logic switches in low-cost radio frequency identification (RFID) flexible tags and bendable display panels. The development of flexible TFT provides broad prospects for future multifunctional flexible electronic systems.

[0003] Bi 2 O 2 As an emerging quasi-two-dimensional van der Waals semiconductor material, Se has many excellent material properties and is considered to be one of the important material platforms for the next generation of electronic and optoelectronic devices. It has also injected new impetus into the development of the flexible TFT field.

[0004] However, the existing COMS (complementary metal oxide semiconductor) production line is designed for manufacturing integrated circuits. The fluorphlogopite substrate is different from the traditional silicon-based or glass substrate. The process and equipment of the COMS production line are not suitable for directly forming Bi on the fluorphlogopite substrate. 2 O 2 Se thin film and corresponding preparation products. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a semiconductor structure with a flexible thin film transistor and a preparation method thereof.

[0006] To achieve the above object, the present invention provides a semiconductor structure having a flexible thin film transistor, comprising: A substrate, a flexible thin film transistor located on the surface of the first area of ​​the substrate, a CMOS process device located on the surface of the second area of ​​the substrate, the flexible thin film transistor is bonded to the substrate, wherein the flexible thin film transistor comprises a fluorophlogopite substrate, the thickness of the fluorophlogopite substrate ranges from 0.02 mm to 0.04 mm, and the Bi 2 O 2 Se thin film layer; located in the Bi 2 O 2 The source and drain on the surface of the Se thin film layer, the gate dielectric layer located between the source and the drain and covering the source and the drain, the gate metal electrode located on the surface of the gate dielectric layer, the gate dielectric layer and the gate metal electrode forming a gate, the fluorphlogopite substrate, the Bi 2 O 2The Se thin film layer, the source electrode, the drain electrode and the gate electrode constitute a flexible thin film transistor.

[0007] Optionally, the gate dielectric layer is a flexible gate dielectric layer.

[0008] Optionally, the material of the gate dielectric layer is ferroelectric polymer.

[0009] Optionally, the substrate is a flexible substrate, and the CMOS process device is a flexible device.

[0010] Optionally, the substrate is a rigid substrate, and a semiconductor device is formed on the surface of the substrate.

[0011] The present invention also provides a method for preparing a semiconductor structure having a flexible thin film transistor, comprising: providing an initial fluorophlogopite substrate; Magnetron sputtering was used to form Bi on the surface of the initial fluorphlogopite substrate. 2 O 2 Se thin film; Etch the Bi on the surface of the initial fluorophlogopite substrate 2 O 2 Se thin film to obtain Bi 2 O 2 Se thin film layer; In the Bi 2 O 2 A source electrode and a drain electrode are formed on the surface of the Se thin film layer, and a gap is provided between the source electrode and the drain electrode; The Bi on the surface of the source and drain, between the source and drain 2 O 2 A gate dielectric layer is formed on the surface of the Se thin film layer; Forming a gate metal electrode on the surface of the gate dielectric layer, wherein the gate dielectric layer and the gate metal electrode constitute a gate; Thinning the initial fluorophlogopite substrate to form a flexible thin film transistor with a fluorophlogopite substrate having a target thickness, wherein the thickness of the fluorophlogopite substrate ranges from 0.02 mm to 0.04 mm; Providing a substrate, wherein a CMOS process device is formed on the surface of the second region of the substrate; The flexible thin film transistor is transferred to the surface of the first region of the substrate to form a semiconductor structure having a flexible thin film transistor.

[0012] Optionally, dilute sulfuric acid is used to treat the Bi 2 O 2 Se film is wet etched to form a patterned Bi 2 O 2 Se thin film layer.

[0013] Optionally, the thickness of the initial fluorophlogopite substrate is greater than 0.1 mm.

[0014] Optional, fluorphlogopite substrate with target thickness, Bi 2 O 2 The Se thin film layer and the gate dielectric layer are both flexible, forming a flexible thin film transistor.

[0015] Optionally, an adhesive layer is formed on the opposite surface of the fluorophlogopite substrate where the source and the drain are formed, and the flexible thin film transistor is transferred to the surface of the substrate through the adhesive layer to form a semiconductor structure with a flexible thin film transistor, or the flexible thin film transistor is directly bonded to the substrate through van der Waals force.

[0016] In summary, the advantages and beneficial effects of the present invention are: The present invention provides a semiconductor structure with a flexible thin film transistor and a preparation method thereof. The flexible thin film transistor based on the fluorophlogopite substrate is directly transferred to a substrate and bonded to the substrate to form a semiconductor structure, which solves the problem that the process and equipment of a COMS production line are not suitable for directly forming Bi on a fluorophlogopite substrate. 2 O 2 Se thin film and the corresponding preparation of products. At the same time, the present invention sets a thin fluorophlogopite substrate, so that the flexible thin film transistor can be better transferred and bonded. At the same time, the thin fluorophlogopite substrate is crucial for the preparation of complex, multi-layer semiconductor structures, avoiding the micro-processing error caused by the substrate of the obtained flexible thin film transistor being too thick. At the same time, setting a thinner fluorophlogopite substrate can also reduce thermal resistance, so that heat can be transferred to the external heat dissipation system faster, reducing the risk of overheating of the semiconductor structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1a~Figure 1b FIG. 1 is a schematic diagram of a semiconductor structure with a flexible thin film transistor provided by an embodiment of the present invention; Figure 2 Shown is a flow chart of a method for preparing a semiconductor structure with a flexible thin film transistor provided by an embodiment of the present invention; Figure 3~Figure 11 Shown is a schematic diagram of a method for preparing a semiconductor structure with a flexible thin film transistor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to facilitate understanding by those skilled in the art, the present invention will be further described in detail below with reference to specific embodiments.

[0019] The present invention provides a semiconductor structure with a flexible thin film transistor, as shown in FIG1 , comprising: A substrate 10, a flexible thin film transistor 20 located on the surface of a first area of ​​the substrate 10, and a CMOS process device 30 located on the surface of a second area of ​​the substrate 10, wherein the flexible thin film transistor 20 is connected to the substrate 10 through an adhesive layer 208, wherein the flexible thin film transistor 20 includes a fluorophlogopite substrate 201 located on the surface of the adhesive layer 208, the thickness of the fluorophlogopite substrate 201 is in the range of 0.02 mm to 0.04 mm, and the Bi 2 O 2 Se thin film layer 202; located in the Bi 2 O 2 The source 203 and the drain 204 on the surface of the Se thin film layer 202, the gate dielectric layer 205 located between the source 203 and the drain 204 and covering the source 203 and the drain 204, the gate metal electrode 206 located on the surface of the gate dielectric layer 205, the gate dielectric layer 205 and the gate metal electrode 206 constitute a gate 207, the fluorphlogopite substrate 201, the Bi 2 O 2 The Se thin film layer 202 , the source electrode 203 , the drain electrode 204 and the gate electrode 207 constitute a flexible thin film transistor 20 .

[0020] Specifically, in the embodiment of the present invention, the thickness of the fluorophlogopite substrate is in the range of 0.02 mm to 0.04 mm, so that the fluorophlogopite substrate is flexible, and correspondingly, the constructed flexible thin film transistor is flexible.

[0021] Since the key parameter of the mechanical flexibility of a material is the bending stiffness, the smaller the bending stiffness, the better the flexibility of the material, and the bending stiffness is positively correlated with the thickness of the material, therefore, the thinner the fluorophlogopite substrate, that is, the fluorophlogopite substrate is set to 0.02 mm~0.04 mm, the smaller the bending stiffness, the better the flexibility of the fluorophlogopite substrate, and correspondingly, the better the flexibility of the constructed flexible thin film transistor.

[0022] At the same time, the present invention selects a thin fluorophlogopite substrate with a smaller bending stiffness, so that the formed flexible thin film transistor is easier to bend and has a higher conformality with the substrate, so that the transfer and bonding processes can be better performed, which is crucial for preparing complex, multi-layer semiconductor structures. The substrate of the obtained flexible thin film transistor is too thick, resulting in micro-machining errors. In addition, the thin fluorophlogopite substrate can reduce thermal resistance, allowing heat to be transferred to the external heat dissipation system more quickly, reducing the risk of overheating of the semiconductor structure.

[0023] In an embodiment of the present invention, the source electrode includes an In metal layer and an Au metal layer, wherein the In metal layer is located adjacent to the Bi 2 O2 The surface of the Se thin film layer 202, the Au metal layer is located on the surface of the In metal layer; the drain includes an In metal layer and an Au metal layer, the In metal layer is located on the surface of the Bi 2 O 2 The surface of the Se thin film layer 202, and the Au metal layer is located on the surface of the In metal layer.

[0024] In the embodiment of the present invention, the thickness of the In metal layer of the source electrode and the In metal layer of the drain electrode is 20 nm, and the thickness of the Au metal layer of the source electrode and the Au metal layer of the drain electrode is 20 nm.

[0025] In an embodiment of the present invention, through holes are formed in the gate dielectric layer corresponding to the source and the drain, and metal is deposited in the through holes, so that the source and the drain are electrically connected to parts other than the flexible thin film transistor.

[0026] In other embodiments, the source electrode and the drain electrode are electrically connected to portions other than the flexible thin film transistor through other suitable means.

[0027] In an embodiment of the present invention, the gate dielectric layer is a flexible gate dielectric layer.

[0028] In an embodiment of the present invention, the material of the gate dielectric layer is a ferroelectric polymer. Specifically, the gate dielectric layer is poly (vinylidene fluoride-trifluoroethylene) (P (VDF-TrFE)) By utilizing the ferroelectricity of P(VDF-TrFE), the formed semiconductor device has the characteristics of high-speed reading and writing and low power consumption. 2 O 2 The synergistic effect of Se and flexible ferroelectric gate constructs a strain-insensitive (i.e., strain-invariant) flexible thin-film transistor, and the corresponding semiconductor devices formed effectively improve the performance of non-volatile memory and artificial neural synapses.

[0029] In the embodiment of the present invention, the material of the gate metal electrode is Au, and the thickness of the gate metal electrode is 80 nm.

[0030] In the embodiment of the present invention, the substrate is a flexible substrate, and the CMOS process device is a flexible device.

[0031] The present invention adopts a flexible fluorphlogopite substrate, Bi 2 O 2Se thin film layer and gate dielectric layer, construct a flexible thin film transistor with flexibility. When the substrate is a flexible substrate, the semiconductor device obtained based on the flexible thin film transistor is strain insensitive and has good flexibility and bendability. It is suitable for preparing wearable devices, flexible displays, flexible sensors, etc., to achieve stable performance of flexible electronic devices. At the same time, based on Bi 2 O 2 The non-volatile storage property of Se enables permanent storage of data and improves the performance of the semiconductor structure.

[0032] In other embodiments, the substrate is a rigid substrate, and a semiconductor device is formed on a surface of the substrate.

[0033] In other embodiments, the substrate is a silicon substrate, a silicon carbide substrate, a sapphire substrate, a glass substrate or other suitable substrates.

[0034] In other embodiments, Figure 1b As shown, the semiconductor structure does not have an adhesive layer, and the flexible thin film transistor can be directly bonded to the substrate by van der Waals force, or bonded by other suitable methods.

[0035] The embodiment of the present invention also provides a method for preparing a semiconductor structure having a flexible thin film transistor, such as Figure 2 As shown, including: Step S10, providing an initial fluorophlogopite substrate; Step S20, using radio frequency magnetron sputtering to form Bi on the surface of the initial fluorphlogopite substrate 2 O 2 Se thin film; Step S30, etching the Bi 2 O 2 Se thin film to obtain Bi 2 O 2 Se thin film layer; Step S40, in the Bi 2 O 2 A source electrode and a drain electrode are formed on the surface of the Se thin film layer, and a gap is provided between the source electrode and the drain electrode; Step S50, Bi on the surface of the source and drain, between the source and drain 2 O 2 A gate dielectric layer is formed on the surface of the Se thin film layer; Step S60, forming a gate metal electrode on the surface of the gate dielectric layer, wherein the gate dielectric layer and the gate metal electrode constitute a gate; Step S70, thinning the initial fluorophlogopite substrate to form a flexible thin film transistor with a fluorophlogopite substrate having a target thickness, wherein the thickness of the fluorophlogopite substrate ranges from 0.02 mm to 0.04 mm; Step S80, providing a substrate, wherein a CMOS process device is formed on the surface of the second region of the substrate; Step S90, forming an adhesive layer on the opposite surface of the fluorophlogopite substrate where the source and the drain are formed, and transferring the flexible thin film transistor to the first area surface of the substrate through the adhesive layer to form a semiconductor structure with a flexible thin film transistor.

[0036] Specifically, Figure 3 As shown, step S10 is performed to provide an initial fluorophlogopite substrate 21 .

[0037] In the embodiment of the present invention, the fluorophlogopite is cleaved by mechanical stripping to obtain the initial fluorophlogopite substrate 21 .

[0038] In the embodiment of the present invention, the thickness of the initial fluorphlogopite substrate 21 is greater than 0.1 mm, which ensures that the initial fluorphlogopite substrate 21 has a certain supporting force to facilitate the subsequent Bi 2 O 2 Formation of Se thin film.

[0039] In other embodiments, the thickness of the initial fluorphlogopite initial substrate is set according to the requirements to ensure that the initial fluorphlogopite initial substrate can be flattened to facilitate the formation of Bi 2 O 2 Se thin film.

[0040] Step S20 is performed to form Bi on the surface of the initial fluorphlogopite substrate by radio frequency magnetron sputtering. 2 O 2 Se thin film.

[0041] Existing preparation of Bi 2 O 2 Se thin film production processes include chemical vapor deposition, molecular beam epitaxy, etc. Chemical vapor deposition preparation of Bi 2 O 2Se thin films usually require higher temperatures, which can cause damage or deformation of the substrate material, limiting its scope of application. It also involves the use and processing of multiple gases. The purity and flow control of the gas are crucial to the quality of the film, increasing the complexity of the operation. In addition, when producing large-area thin films, the uniformity of the film faces serious challenges, and the chemical vapor deposition technology will produce side reactions, resulting in the generation of unnecessary deposits or impurities, thus affecting the performance and quality of the film. Molecular beam epitaxy technology mainly has the problems of high cost and slow growth rate. In addition, molecular beam epitaxy equipment is expensive, and the operation and maintenance costs are also high. The growth rate of molecular beam epitaxy is also low, usually at a few nanometers per hour, which limits its application in large-scale production.

[0042] The present invention adopts radio frequency magnetron sputtering to form Bi 2 O 2 Se thin film, to a certain extent, avoids the existing chemical vapor deposition, molecular beam epitaxy and other defects such as high cost, low deposition rate, high thermal budget. 2 O 2 Se thin film is formed on the surface of the initial fluorphlogopite substrate, and Bi can be realized without any subsequent transfer process. 2 O 2 The application of Se thin film in the flexible field has been expanded, and the complex device preparation process has been simplified, making it more operable. Since the present invention adopts the radio frequency magnetron sputtering process, the initial fluorphlogopite substrate needs to be placed upside down in the cavity. Therefore, the initial fluorphlogopite substrate needs to have a certain thickness and cannot be too thin to ensure that the initial fluorphlogopite substrate has a certain supporting force to facilitate the subsequent Bi 2 O 2 Formation of Se thin film.

[0043] In the embodiment of the present invention, radio frequency magnetron sputtering is used to form the Bi 2 O 2 The steps of Se film include: Step S201, provide and install Bi 2 O 2 Se ceramic target, the initial fluorphlogopite substrate is mounted on a substrate tray in a magnetron sputtering chamber; In the embodiment of the present invention, the initial fluorphlogopite substrate and the Bi 2 O 2 The distance between the Se ceramic target and the target is in the range of 9 cm to 12 cm, specifically 10.5 cm.

[0044] Step S202, evacuating the magnetron sputtering chamber; In the embodiment of the present invention, a mechanical pump and a molecular pump are used to reduce the gas pressure in the magnetron sputtering chamber to 10-4 Pa below, in order to reduce the background gas to the back Bi 2 O 2 The influence of Se thin film growth quality.

[0045] Step S203, heating the substrate tray in the magnetron sputtering chamber, introducing working gas and adjusting the gas pressure in the sputtering chamber to the working pressure; In an embodiment of the present invention, the temperature range of heating the substrate tray in the magnetron sputtering chamber is 600°C to 700°C, specifically 650°C.

[0046] In an embodiment of the present invention, the working gas is argon.

[0047] In the embodiment of the present invention, the working gas pressure in the sputtering chamber is 1 Pa~2 Pa, specifically 1.5 Pa.

[0048] Step S204, turning on the magnetron sputtering radio frequency target source, setting the sputtering power, and adjusting the vacuum degree and the flow rate of the working gas in the magnetron sputtering chamber.

[0049] In the embodiment of the present invention, the sputtering power range is 5 W to 10 W, the working gas pressure in the magnetron sputtering chamber is adjusted to a range of 0.1 Pa to 1 Pa, and the flow rate of argon gas during the RF magnetron sputtering is in the range of 10 sccm to 20 sccm. Specifically, the sputtering power is 10 W, the rotation speed of the substrate tray is 3 r / min, the flow rate of argon gas is 10 sccm, and the vacuum degree in the magnetron sputtering chamber is adjusted to 0.1 Pa.

[0050] Step S205: 2 O 2 Se ceramic target was pre-sputtered; In the embodiment of the present invention, the Bi 2 O 2 The pre-sputtering time of the Se ceramic target is in the range of 10 min to 30 min, and specifically, the pre-sputtering time is 15 min.

[0051] Step S206, sputtering deposition is performed on the surface of the initial fluorphlogopite substrate to form Bi 2 O 2 Se thin film; In the embodiment of the present invention, sputtering deposition is performed on the surface of the initial fluorphlogopite substrate to form Bi 2 O 2 The time range of Se film is 18 min~22 min, and the Bi 2 O 2The thickness of the Se film ranges from 20 nm to 25 nm. Specifically, the deposition time is 20 min. 2 O 2 The thickness of the Se film is 22 nm.

[0052] Step S207, after the deposition is completed, the gas pressure in the magnetron sputtering chamber is adjusted, the substrate tray is cooled, and the substrate tray is taken out and the Bi 2 O 2 Initial fluorophlogopite substrate for Se thin films.

[0053] In an embodiment of the present invention, after deposition is completed, working gas is introduced into the magnetron sputtering chamber so that the gas pressure in the magnetron sputtering chamber is adjusted to 10 Pa. After keeping warm for 30 minutes, the substrate tray is cooled to room temperature at a cooling rate of 10 °C / min.

[0054] Execute step S30, such as Figure 4 As shown, the Bi on the surface of the initial fluorophlogopite substrate is etched 2 O 2 Se thin film to obtain Bi 2 O 2 Se thin film layer 202 .

[0055] In the embodiment of the present invention, dilute sulfuric acid is used to treat the Bi 2 O 2 Se film is wet etched to form a patterned Bi 2 O 2 Se thin film layer 202 .

[0056] In other embodiments, dilute hydrochloric acid or other suitable reagents are used to etch the Bi 2 O 2 Se thin film forms Bi 2 O 2 Se thin film layer.

[0057] Execute step S40, such as Figure 5 As shown in the Bi 2 O 2 A source electrode 203 and a drain electrode 204 are formed on the surface of the Se thin film layer, and a gap is provided between the source electrode 203 and the drain electrode 204 .

[0058] In the embodiment of the present invention, the source electrode 203 includes an In metal layer and an Au metal layer, wherein the In metal layer is located adjacent to the Bi 2 O 2 The surface of the Se thin film layer 202, the Au metal layer is located on the surface of the In metal layer; the drain 204 includes an In metal layer and an Au metal layer, the In metal layer is located on the surface of the Bi2 O 2 The surface of the Se thin film layer 202, and the Au metal layer is located on the surface of the In metal layer.

[0059] In the embodiment of the present invention, the thickness of the In metal layer of the source electrode 203 and the In metal layer of the drain electrode 204 is 20 nm, and the thickness of the Au metal layer of the source electrode 203 and the Au metal layer of the drain electrode 204 is 20 nm.

[0060] In or Au can effectively slow down the deposition of Bi during electrode evaporation. 2 O 2 Destruction of the Se thin film layer 202.

[0061] In the embodiment of the present invention, the source and drain are formed by photolithography and evaporation process.

[0062] Execute step S50, such as Figure 6 As shown, on the surface of the source 203 and the drain 204, the Bi between the source 203 and the drain 204 2 O 2 A gate dielectric layer 205 is formed on the surface of the Se thin film layer 202 .

[0063] In the embodiment of the present invention, the material of the gate dielectric layer 205 is poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)).

[0064] In the embodiment of the present invention, the Bi on the surface of the source 203 and the drain 204, between the source 203 and the drain 204 2 O 2 The step of forming a gate dielectric layer 205 on the surface of the Se thin film layer 202 includes: The Bi on the surface of the source 203 and the drain 204, between the source 203 and the drain 204 2 O 2 The surface of Se thin film layer 202 is spin-coated with P (VDF-TrFE); After annealing in vacuum, a gate dielectric layer 205 is obtained.

[0065] In the embodiment of the present invention, the thickness of the spin-coated P(VDF-TrFE) ranges from 100 nm to 150 nm. Specifically, the P(VDF-TrFE) is spin-coated three times, and the thickness of each spin coating is 150 nm.

[0066] In the embodiment of the present invention, the annealing temperature ranges from 120 ° C to 140 ° C, and the annealing time ranges from 5 hours to 7 hours. Specifically, the annealing temperature is 135 ° C, and the annealing time is 6 hours.

[0067] Execute step S60, such as Figure 7~Figure 8 As shown, a gate metal electrode 206 is formed on the surface of the gate dielectric layer 205 , and the gate dielectric layer 205 and the gate metal electrode 206 constitute a gate 207 .

[0068] In the embodiment of the present invention, the gate metal electrode 206 is transferred by a PDMS-assisted dry method.

[0069] In the embodiment of the present invention, the material of the gate metal electrode 206 is Au, and the thickness of the gate metal electrode 206 is 80 nm.

[0070] Execute step S70, such as Fig. 9 As shown, the initial fluorphlogopite substrate 21 is thinned to form a flexible thin film transistor 20 having a fluorphlogopite substrate 201 of target thickness, wherein the thickness of the fluorphlogopite substrate 201 ranges from 0.02 mm to 0.04 mm; In an embodiment of the present invention, the initial fluorophlogopite substrate is thinned by mechanical stripping, so that the obtained fluorophlogopite substrate is flexible, and correspondingly, the formed flexible thin film transistor is also flexible.

[0071] In other embodiments, other suitable methods may be used to thin the initial fluorophlogopite substrate.

[0072] The thinner the fluorophlogopite substrate is, the smaller the bending stiffness is, making the fluorophlogopite substrate more flexible, and also making the formed flexible thin film transistors transfer better and bond better to the substrate, which is crucial for preparing complex, multi-layer semiconductor structures, and avoiding the use of the substrate in high-precision processing due to the substrate being too thick. At the same time, setting a thinner fluorophlogopite substrate can reduce thermal resistance, allowing heat to be transferred to the external heat dissipation system more quickly, reducing the risk of overheating of the semiconductor structure.

[0073] In other embodiments, Bi is formed on the surface of the initial fluorphlogopite substrate. 2 O 2 The initial fluorophlogopite substrate is thinned at any step after the Se thin film is formed and before the adhesive layer is formed to form a fluorophlogopite substrate with a target thickness.

[0074] Step S80 is performed to provide a substrate 10 , wherein a CMOS process device 30 is formed on the surface of the second region of the substrate.

[0075] In the embodiment of the present invention, the substrate 10 is a flexible substrate, and the CMOS process device 30 is a flexible device.

[0076] In other embodiments, the substrate is a rigid substrate, and a semiconductor device is formed on a surface of the substrate.

[0077] Execute step S90, such as Figure 10~Figure 11 As shown, an adhesive layer 208 is formed on the opposite side of the fluorophlogopite substrate 201 where the source and the drain are formed, and the flexible thin film transistor 20 is transferred to the first area surface of the substrate 10 through the adhesive layer 208 to form a semiconductor structure having the flexible thin film transistor 20.

[0078] In other embodiments, no adhesive layer is formed on the opposite side of the fluorophlogopite substrate where the source and the drain are formed, and the flexible thin film transistor can be directly bonded to the substrate through van der Waals force, or bonded to the substrate through other suitable methods.

[0079] In the embodiment of the present invention, the flexible thin film transistor 20 based on the fluorphlogopite substrate 201 can be directly transferred to the substrate 10 to form a semiconductor structure, which solves the problem that the process and equipment of the COMS production line are not suitable for directly forming Bi on the fluorphlogopite substrate. 2 O 2 Se thin film and corresponding preparation products.

[0080] Finally, it is to be noted that any modification or equivalent replacement of part or all of the technical features based on the device structure of the present invention and the technical solution of the described embodiment, which does not deviate from the essence of the corresponding technical solution of the present invention, belongs to the patent scope of the device structure of the present invention and the described implementation scheme.

Claims

1. A semiconductor structure having a flexible thin film transistor, characterized in that: include: A substrate, a flexible thin film transistor located on the surface of a first area of ​​the substrate, and a CMOS process device located on the surface of a second area of ​​the substrate, wherein the flexible thin film transistor is bonded to the substrate, wherein the flexible thin film transistor comprises a fluorophlogopite substrate, the thickness of the fluorophlogopite substrate ranges from 0.02 mm to 0.04 mm, a Bi2O2Se thin film layer located on the surface of the fluorophlogopite substrate; a source and a drain located on the surface of the Bi2O2Se thin film layer, a gate dielectric layer located between the source and the drain and covering the source and the drain, a gate metal electrode located on the surface of the gate dielectric layer, the gate dielectric layer and the gate metal electrode constitute a gate, and the fluorophlogopite substrate, the Bi2O2Se thin film layer, the source, the drain and the gate constitute a flexible thin film transistor.

2. A semiconductor structure with a flexible thin film transistor as claimed in claim 1, characterized in that: The gate dielectric layer is a flexible gate dielectric layer.

3. The semiconductor structure with a flexible thin film transistor according to claim 1, characterized in that: The material of the gate dielectric layer is ferroelectric polymer.

4. The semiconductor structure with a flexible thin film transistor according to claim 1, characterized in that: The substrate is a flexible substrate, and the CMOS process device is a flexible device.

5. The semiconductor structure with a flexible thin film transistor according to claim 1, characterized in that: The substrate is a rigid substrate, and a semiconductor device is formed on the surface of the substrate.

6. A method for preparing a semiconductor structure having a flexible thin film transistor, characterized in that: include: providing an initial fluorophlogopite substrate; The Bi2O2Se film was formed on the surface of the initial fluorophlogopite substrate by magnetron sputtering; Etching the Bi2O2Se film on the surface of the initial fluorophlogopite substrate to obtain a patterned Bi2O2Se film layer; Forming a source electrode and a drain electrode on the surface of the Bi2O2Se thin film layer, with a gap between the source electrode and the drain electrode; Forming a gate dielectric layer on the surfaces of the source and drain electrodes and on the surface of the Bi2O2Se thin film layer between the source and drain electrodes; Forming a gate metal electrode on the surface of the gate dielectric layer, wherein the gate dielectric layer and the gate metal electrode constitute a gate; Thinning the initial fluorophlogopite substrate to form a flexible thin film transistor with a fluorophlogopite substrate having a target thickness, wherein the thickness of the fluorophlogopite substrate ranges from 0.02 mm to 0.04 mm; Providing a substrate, wherein a CMOS process device is formed on the surface of the second region of the substrate; The flexible thin film transistor is transferred to the surface of the first region of the substrate to form a semiconductor structure having a flexible thin film transistor.

7. The method for preparing a semiconductor structure having a flexible thin film transistor according to claim 6, characterized in that: The Bi2O2Se film is wet-etched with dilute sulfuric acid to form a patterned Bi2O2Se film layer.

8. The method for preparing a semiconductor structure having a flexible thin film transistor according to claim 6, characterized in that: The thickness of the initial fluorophlogopite substrate is greater than 0.1 mm.

9. The method for preparing a semiconductor structure having a flexible thin film transistor according to claim 6, characterized in that: The fluorophlogopite substrate, Bi2O2Se thin film layer and gate dielectric layer with target thickness are all flexible, forming a flexible thin film transistor.

10. The method for preparing a semiconductor structure having a flexible thin film transistor according to claim 6, characterized in that: An adhesive layer is formed on the opposite surface of the fluorophlogopite substrate where the source and the drain are formed, and the flexible thin film transistor is transferred to the surface of the substrate through the adhesive layer to form a semiconductor structure with a flexible thin film transistor, or the flexible thin film transistor is directly bonded to the substrate through van der Waals force.

Images