Preparation method of binary metal doped oxide printing thin film transistor
Printing was solved by printing on a silicon/silica substrate using precursor solutions of zinc acetate dihydrate and indium nitrate hydrate and stannous chloride dihydrate on a silicon/silica substrate and performing high-temperature annealing The problem of regulating semiconductor layer components in thin film transistors improves the device's field effect performance and carrier transport capability.
Patent Information
- Application Number
- CN202410937695.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-12
- Publication Date
- 2024-12-13
AI Technical Summary
In the prior art, the semiconductor layer component regulation of printed metal oxide thin film transistors is not yet mature, and in particular, there are difficulties in preparing the printed binary metal doping thin film transistors.
Ultrasonic cleaning and argon plasma treatment were used with silicon/silica substrates, zinc acetate dihydrate and indium nitrate hydrate as precursor solutions for indium zinc oxygen, and stannous chloride dihydrate and indium nitrate hydrate as indium tin The precursor solution of oxygen is prepared by a high-precision micro-nano printing device, a dumbbell-like patterned binary doped metal oxide semiconductor layer is carried out, and a high-temperature annealing is performed, and a top-contact thin film transistor is formed by inkjet printing silver nanowire particles.
The preparation of binary metal doped oxide thin film transistors is realized, which improves the field effect performance of the device. Especially in vacuum atmosphere, the indium zinc oxygen thin film transistors show higher threshold voltage, switching ratio and field effect mobility. Reduces off-state current and power consumption, and improves carrier transport capacity.
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Figure CN119132966A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of printed device preparation, and in particular relates to a method for preparing a binary metal-doped oxide printed thin film transistor. Background Art
[0002] With the gradual development of electronic display devices, the requirements for the performance and preparation process of driving components are also gradually increasing. Among them, the field effect performance of thin film transistors affects the image quality of display devices. In the current research field, the semiconductor layer of inorganic thin film transistor devices can use stable metal oxide materials. The metal oxide doping components are easy to control and optimize the overall electrical properties of thin film transistor devices. At present, the preparation process of metal oxide thin film transistor devices mainly relies on traditional vacuum deposition processes, although it has the advantages of high film quality and low interface defect state density. But at the same time, the device patterning structure requires vacuum evaporation, repeated photolithography, and overlay, which makes the process complicated and affects the large-scale preparation of devices, and there are problems such as material waste and environmental pollution. In contrast, the use of printing technology to prepare thin film transistor devices is not limited by the vacuum preparation environment, and has the advantages of more flexible material composition ratio control and low substrate selectivity.
[0003] However, the regulation of semiconductor layer components of printed metal oxide thin film transistors is still in the preliminary research stage and needs further exploration. In order to solve this problem, the advantages of flexible material composition ratio regulation in printing preparation are brought into play, and the influence of metal oxide element doping on the field effect performance of thin film transistors is explored. At present, most studies are based on indium gallium zinc oxide as semiconductor layer materials for application in metal oxide thin film transistor devices. Further research is needed to reduce the amount of metal element doping in the semiconductor layer to form a printable binary metal-doped oxide thin film transistor. Therefore, at this stage, there is an urgent need for a preparation process for printed metal oxide thin film transistors with a simple process and controllable element doping ratio in the semiconductor layer. Summary of the invention
[0004] The technical problem to be solved by the present invention is to provide a method for preparing a binary metal-doped oxide printed thin film transistor in view of the problem that the existing multi-element doped metal oxide thin film transistor has too many doped elements.
[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows:
[0006] A method for preparing a binary metal-doped oxide printed thin film transistor is provided, comprising the following steps:
[0007] S1. Cutting a silicon / silicon dioxide (silicon dioxide thickness is 285 nm) substrate, the silicon / silicon dioxide substrate needs to be ultrasonically cleaned in acetone, ethanol, and high-purity water for 10 minutes in sequence;
[0008] S2, placing the clean silicon / silicon dioxide substrate in argon plasma to remove the surface adsorbed functional groups, which is conducive to the subsequent printing of the patterned binary doped metal oxide semiconductor layer material;
[0009] S3, zinc acetate dihydrate Zn(CH 3 COO 2 ·2H 2 O and hydrated indium nitrate In(NO 3 ) 3 ·xH 2 O as the zinc source and indium source of indium zinc oxide are dissolved in ethylene glycol methyl ether solvent in sequence to prepare a precursor solution with a concentration of 0.4 mol / L;
[0010] S4, tin(II) chloride dihydrate SnCl 2 ·2H 2 O and hydrated indium nitrate In(NO 3 ) 3 ·xH 2 O as the tin source and indium source of indium tin oxide are dissolved in ethylene glycol methyl ether solvent in sequence to prepare a precursor solution with a concentration of 0.4 mol / L;
[0011] S5. Using high-precision micro-nano printing equipment to prepare dumbbell-shaped patterned binary doped metal oxide semiconductor layer materials;
[0012] S6, high temperature annealing to treat organic impurities to improve the electrical properties of the printed binary doped metal oxide semiconductor layer;
[0013] S7. Use high-precision printing equipment to inkjet print silver nanowire particle ink to form source and drain electrodes of top-contact thin-film transistors.
[0014] The selection and preparation method of semiconductor layer materials in printed metal oxide thin film transistor devices are key factors in determining the field effect performance of thin film transistors. Because metal oxides have excellent electrical and environmental stability, metal oxide materials are preferred as semiconductor layers of thin film transistor devices. In order to reduce the influence of the amount of doped metal elements on the carrier transport capacity of the semiconductor layer, binary metal-doped oxides are preferred as printing inks to prepare semiconductor layers of thin film transistors with controllable component elements. First, a silicon / silicon dioxide substrate with a clean surface and good wettability is used as a substrate for binary metal-doped oxide printed thin film transistors, wherein silicon is used as the gate of this bottom-gate top-contact thin film transistor, and thermally oxidized silicon dioxide is used as a dielectric layer. It is preferred to perform ultrasonic cleaning in acetone, ethanol, and high-purity water for 10 minutes to remove organic impurities on the silicon / silicon dioxide substrate, improve the wettability of the substrate surface, and blow dry the surface with nitrogen to prevent water marks. In order to further improve the wettability of the substrate surface, it is preferred to place the cleaned and nitrogen-dried silicon / silicon dioxide substrate in argon plasma. High-energy argon plasma can remove the functional groups adsorbed on the substrate surface, which is beneficial for the subsequent printing of a graphically controllable binary doped metal oxide semiconductor layer. The preferred plasma treatment time is 10 seconds, and the power supply of the gas plasma generator is set to 75W. The lower gas ionization power and ionization time are not conducive to forming a good substrate surface wettability, so that when printing a graphical binary doped metal oxide semiconductor layer, the printing ink will be locally aggregated, and it is impossible to quickly form a semiconductor layer printing pattern with a controllable morphology of printed lines on the substrate surface.
[0015] The printing ink of the semiconductor layer material in the binary metal-doped oxide printed thin film transistor is composed of zinc acetate dihydrate Zn(CH 3 COO 2 ·2H 2 O and hydrated indium nitrate In(NO 3 ) 3 ·xH 2 O is used as the zinc source and indium source of the indium zinc oxide semiconductor layer, and is dissolved in ethylene glycol methyl ether solvent in turn to prepare an indium zinc oxide binary metal-doped oxide precursor solution with a concentration of 0.4 mol / L, and is stirred for 1 hour under heating conditions at 150°C to facilitate the dissolution of the zinc source and the indium source in the ethylene glycol methyl ether solvent, thereby ensuring that the concentration of the obtained printing ink solution is consistent with the concentration of the precursor solution calculated in advance. The preferred concentration of the precursor solution is 0.4 mol / L. When the concentration is high, the graphic lines printed using high-precision micro-nano printing equipment are prone to agglomeration, which is not conducive to the controllable preparation of the semiconductor layer graphics. The precursor solution is low and cannot form a high-quality and continuous graphic semiconductor layer. The controllable carrier concentration in the semiconductor layer is too low, which is not conducive to the formation of better thin-film transistor field effect performance. Another binary metal-doped oxide ink is stannous chloride dihydrate SnCl 2 ·2H2 O and hydrated indium nitrate In(NO 3 ) 3 ·xH 2 O as the tin source and indium source of the indium tin oxide semiconductor layer are dissolved in ethylene glycol methyl ether solvent in sequence to prepare a precursor solution with the same concentration of 0.4 mol / L, and other preparation conditions are consistent with the printable indium zinc oxide ink.
[0016] The preferred binary metal-doped oxide semiconductor layer pattern has a length and width of 840 μm and 560 μm, respectively. The purpose of printing a dumbbell-shaped patterned semiconductor layer is to obtain more carrier injection when the same voltage is applied to the source and drain. A needle with a diameter of 5 μm is selected, and the printing voltage is set to 0.6 V. The preferred printing line spacing is 40 μm, so that the printed lines are continuous and a thinner patterned binary metal-doped semiconductor layer is obtained. The patterned semiconductor layer needs to be heated and cured for 3 minutes after the printed pattern is printed, and the temperature of the heating plate is set to 90 ° C to control the printed pattern boundary solution from diffusing to the surroundings. Then, the binary metal-doped oxide semiconductor layer prepared by printing on the silicon / silicon dioxide substrate is annealed at 550 ° C to remove the residual organic impurities in the patterned semiconductor layer. Two annealing methods were compared, one was annealed at 550 ° C in an air atmosphere for 1 hour, and the other was annealed at 550 ° C in a vacuum atmosphere for 1 hour. The vacuum degree of the vacuum atmosphere annealing was 0.5 hPa, and the heating rate of both annealings was 5 ° C / minute.
[0017] The silver nanowire particle ink is printed by inkjet printing using high-precision printing equipment to form the source and drain electrodes of the top-contact thin-film transistor. The structural diagram is shown in the figure. Figure 1 As shown. The preferred printed silver nanoparticle source and drain electrodes need to be cured at 90°C for 5 minutes to maintain the morphology of the rectangular source and drain electrodes. The printed thin-film transistor device is then annealed in an air atmosphere at 200°C for 1 hour to allow the silver nanoparticles to connect to each other, thereby ensuring the excellent electron transport capability of the printed binary metal-doped oxide thin-film transistor source and drain electrodes. By testing the output and transfer curves of the thin-film transistor device, the field effect performance of the two types of printed binary metal-doped oxide thin-film transistors is analyzed, mainly focusing on the thin-film transistor's ability to regulate the source and drain currents, and calculating and comparing the values of the four field effect performance parameters: field effect mobility, threshold voltage, current switching ratio, and subthreshold swing. As shown Figure 2 As shown in Figure 2, the transfer characteristic curves of the printed binary metal-doped oxide indium zinc oxide thin film transistor after annealing in air and vacuum atmosphere, respectively, and the applied source-drain voltage (V DS ) is 20V, the gate voltage (V GS ) is swept from -30V to 30V. By calculation, the threshold voltage (V T) is -5.7V, and the subthreshold swing (SS) is 1.41Vdec -1 , switching ratio (I on / I off ) is 3.1×10 5 and field effect mobility (μ) is 0.04 cm 2 / Vs. After vacuum annealing, the indium zinc oxide thin film transistor device showed V T is -4.4V, SS is 1.31V dec -1 , I on / I off 5.3×10 5 and field effect mobility μ is 0.08 cm 2 / Vs. In contrast, the transfer characteristic curves of another printed binary metal-doped oxide indium tin oxide thin film transistor after annealing in air and vacuum atmosphere are shown in Figure 2. Figure 3 As shown, the applied V DS is 20V, V GS Sweep from -30V to 30V. By calculation, the threshold voltage V of the indium tin oxide thin film transistor device after air atmosphere annealing is obtained. T is -15.1V, SS is 4.23V dec -1 , I on / I off 2.3×10 3 and μ is 0.03cm 2 / Vs. After vacuum annealing, the indium tin oxide thin film transistor device showed V T -16.6V, SS is 3.29Vdec -1 , I on / I off 5.4×10 4 and field effect mobility μ is 0.06 cm 2 / Vs. The field effect performance of the preferred binary metal-doped oxide indium zinc oxide thin film transistor device in air atmosphere and vacuum atmosphere is higher than that of the indium tin oxide thin film transistor device. The binary metal-doped oxide indium zinc oxide thin film transistor has a lower off-state current than the indium tin oxide thin film transistor, which makes the binary metal-doped oxide indium zinc oxide thin film transistor have a higher I on / I off , improving the ability of thin film transistor current switch to resist signal noise interference. At the same time, the V of indium zinc oxide thin film transistor is higher than that of indium zinc oxide thin film transistor device. T Greatly improved, V TThe reduction in the absolute value of can effectively reduce the power consumption of binary metal-doped oxide thin-film transistor devices. And after annealing in the same atmosphere, the indium zinc oxide thin-film transistor has a higher field effect mobility than the indium tin oxide thin-film transistor device, which improves the switching speed of the binary metal-doped oxide thin-film transistor device. The SS value of the indium zinc oxide thin-film transistor has also been significantly reduced, indicating that the binary metal-doped oxide indium zinc oxide thin-film transistor device switches from the off state to the on state more quickly. The field effect performance of the device after annealing in air atmosphere and vacuum atmosphere of the preferred binary metal-doped oxide indium zinc oxide was compared, and it was found that vacuum annealing was faster than air annealing. on / I off Value increase, V T The absolute value of decreases, the value of μ increases, and the value of SS decreases. Part of the controllable carriers in metal-doped oxide thin-film transistors originate from oxygen vacancies. The vacuum atmosphere can effectively prevent the filling of oxygen vacancies during annealing, increase the carrier concentration in the semiconductor layer, and thus improve the overall electrical performance of binary metal-doped oxide thin-film transistor devices. From then on, a method for preparing binary metal-doped oxide thin-film transistors that can be printed was formed. Compared with multi-metal-doped oxide thin-film transistor devices, binary doped metal ions are more conducive to regulation, providing more new ideas for component regulation for expanding the preparation of printed metal oxide thin-film transistor devices. This provides strong support for the future application of various types of printed electronic components in display devices. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a schematic diagram of the structure of printed binary metal-doped oxide thin film transistor;
[0019] Figure 2 Transfer characteristic curves of thin film transistors prepared after annealing in air atmosphere and vacuum atmosphere for binary metal doped indium zinc oxygen;
[0020] Figure 3 Transfer characteristic curves of thin film transistors prepared after binary metal doped indium tin oxygen air atmosphere annealing and vacuum atmosphere annealing.
Claims
1. A method for preparing a binary metal-doped oxide printed thin film transistor, characterized in that: The following steps are involved: S1. Cutting a silicon / silicon dioxide (silicon dioxide thickness is 285 nm) substrate, the silicon / silicon dioxide substrate needs to be ultrasonically cleaned in acetone, ethanol, and high-purity water for 10 minutes in sequence; S2, placing the clean silicon / silicon dioxide substrate in argon plasma to remove the surface adsorbed functional groups, which is conducive to the subsequent printing of the patterned binary doped metal oxide semiconductor layer material; S3, zinc acetate dihydrate Zn(CH3COO)2·2H2O and hydrated indium nitrate In(NO3)3·xH2O as zinc source and indium source of indium zinc oxide are dissolved in ethylene glycol methyl ether solvent in sequence to prepare a precursor solution with a concentration of 0.4 mol / L; S4, stannous chloride dihydrate SnCl2·2H2O and hydrated indium nitrate In(NO3)3·xH2O as tin source and indium source of indium tin oxide are dissolved in ethylene glycol methyl ether solvent in sequence to prepare a precursor solution with a concentration of 0.4 mol / L; S5. Using high-precision micro-nano printing equipment to prepare dumbbell-shaped patterned binary doped metal oxide semiconductor layer materials; S6, high temperature annealing to treat organic impurities to improve the electrical properties of the printed binary doped metal oxide semiconductor layer; S7. Use high-precision printing equipment to inkjet print silver nanowire particle ink to form source and drain electrodes of top-contact thin-film transistors.
2. The preparation method according to claim 1, characterized in that: In the step S1, the silicon / silicon dioxide substrate is cut into squares with a length and width of 1.5 cm, the cut substrate is ultrasonically cleaned in acetone, anhydrous ethanol, and deionized water for 10 minutes, and the surface of the silicon / silicon dioxide substrate is dried with nitrogen.
3. The preparation method according to claim 1, characterized in that: In step S2, the silicon / silicon dioxide substrate is placed in an argon plasma generator with a power supply of 75 watts and a substrate surface plasma treatment time of 10 seconds to improve the wettability of the substrate surface.
4. The preparation method according to claim 1, characterized in that: In the step S3, zinc acetate dihydrate Zn(CH3COO)2·2H2O and hydrated indium nitrate In(NO3)3·xH2O are used as zinc source and indium source of indium zinc oxide, respectively, and are dissolved in ethylene glycol methyl ether solvent to prepare a precursor solution with a concentration of 0.4 mol / L. The solution is placed in a three-necked flask equipped with a condensing device, heated in an oil bath at 150°C, and stirred evenly for 1 hour. After stirring, the solution is placed for 24 hours until the precursor solution is stable. The solution is filtered through a filter with a pore size of 0.22 μm to form a printable binary doped metal oxide indium zinc oxide ink.
5. The preparation method according to claim 1, characterized in that: In the step S4, stannous chloride dihydrate SnCl2·2H2O and hydrated indium nitrate In(NO3)3·xH2O are used as tin source and indium source of indium tin oxide, respectively, and are dissolved in ethylene glycol methyl ether solvent to prepare a precursor solution with a concentration of 0.4 mol / L. The solution is placed in a three-necked flask equipped with a condenser, heated in an oil bath at 150°C, and stirred evenly for 1 hour. After stirring, the solution is placed for 24 hours until the precursor solution is stable. The solution is filtered through a filter with a pore size of 0.22 μm to form a printable binary doped metal oxide indium tin oxide ink.
6. The preparation method according to claim 1, characterized in that: In step S5, the length and width of the semiconductor layer pattern are 840 μm and 560 μm respectively, a printing needle with a diameter of 5 μm is selected, and the printing line spacing is 40 μm.
7. The preparation method according to claim 1, characterized in that: In the step S6, the printed binary doped metal oxide semiconductor layer is annealed at 550° C. for 1 hour under different gas environments to remove organic impurities mixed in the ink ratio. The annealing treatment is compared in air atmosphere and vacuum atmosphere. The annealing pressure in the vacuum environment is 0.5 hPa, and the heating rate is 5° C. / minute. The lower heating rate is controlled to avoid the formation of surface cracks in the printed patterned metal oxide semiconductor layer during the annealing process.
8. The preparation method according to claim 1, characterized in that: In step S7, the ink for preparing the source and drain electrodes is silver nanoparticles, and the source and drain electrode layers are printed on both sides of the dumbbell-shaped patterned binary-doped metal oxide semiconductor layer to cover the source and drain electrode layers. After printing, they need to be cured on a hot plate at 90° C. for 5 minutes, and then air annealed at 200° C. for 1 hour to remove the organic solvent coated around the silver nanoparticles, thereby improving the electron transport capacity of the printed source and drain electrode layers.