Design Methods of Thin Film Transistors

Abstract

A method for designing a thin film transistor, the method comprising calculating characteristic parameters of a searched material; screening materials according to a characteristic parameter threshold to obtain a first active layer material; simulating the first active layer material as an active layer material in a thin film transistor device model to obtain device characteristics of the thin film transistor device; screening the first active layer material according to the device characteristic threshold to obtain a second active layer material; conducting an experiment using the second active layer material as an active layer material of the thin film transistor device; when the experimental result does not meet the preset requirements, selecting another second active layer material to conduct the experiment again, until the experimental result meets the preset requirements, the design of the thin film transistor device is completed. The present invention can obtain a large number of physical properties related to the active layer materials of thin film transistor devices and a corresponding active layer material database through a simple method, providing theoretical guidance for studying the characteristics of thin film transistor devices.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor transistor devices, and in particular to a design method for a thin film transistor. Background Art

[0002] As a beneficial supplement to field-effect transistors, thin-film transistors have been widely used in display, sensing and other fields in recent years. Compared with field-effect transistors, there are many types of semiconductor materials for preparing thin-film transistors, and the manufacturing process is relatively simple. Relatively cheap large-area spin coating, printing, etc. can be used, so the manufacturing cost is relatively low. In addition, thin-film materials can be produced under relatively low temperature conditions, so materials with poor heat resistance (such as plastic paper and other substrates) can be selected to manufacture lightweight, tough and bendable electronic devices. However, due to the wide variety of materials used to make thin-film transistor devices, there are still many technical problems in the reliability, current characteristics and durability of thin-film transistor devices made of different materials, resulting in no system of thin-film transistor devices that can completely replace existing technologies and dominate the market.

[0003] Currently, people generally use experimental methods to try to improve the comprehensive performance of thin-film transistor devices from aspects such as materials, structure, composition, and testing. However, conducting research through experimental methods not only consumes a lot of time and cost, but also has a relatively slow research process. Compared with experiments, using theoretical methods to study thin-film transistor devices can not only predict, analyze, and optimize device characteristics, but also greatly shorten the research process. However, although the structure of thin-film transistor devices is simple, the factors that affect their characteristics are diverse. Current experimental and theoretical methods are difficult to fully describe the characteristics of thin-film transistor devices. Therefore, developing an effective method to design thin-film transistor devices is of great significance to accelerating the development of thin-film transistors and their practical application in display technology. Summary of the Invention

[0004] In view of this, one of the main objectives of the present invention is to provide a design method for a thin film transistor, in order to at least partially solve at least one of the above technical problems.

[0005] In order to achieve the above object, the present invention provides a thin film transistor design method, comprising:

[0006] Calculate the characteristic parameters of the searched material;

[0007] Screening materials according to characteristic parameter thresholds to obtain first active layer materials;

[0008] Simulating the first active layer material as the active layer material in a thin film transistor device model to obtain device characteristics of the thin film transistor device;

[0009] Screening the first active layer material according to the device characteristic threshold to obtain the second active layer material;

[0010] Conducting experiments using the second active layer material as an active layer material of a thin film transistor device;

[0011] When the experimental results do not meet the preset requirements, another second active layer material is selected to conduct the experiment again until the experimental results meet the preset requirements and the design of the thin film transistor device is completed.

[0012] Based on the above technical solutions, it can be seen that the thin film transistor design method of the present invention has at least one or part of the following advantages over the prior art:

[0013] 1. The present invention can obtain a large number of physical properties related to active layer materials of thin film transistor devices and the corresponding active layer material database through a simple method, providing theoretical guidance for studying the characteristics of thin film transistor devices;

[0014] 2. The present invention provides a simple method for designing thin film transistor devices, thereby saving a large amount of resources in the process of developing thin film transistor devices;

[0015] 3. The method of the present invention is simple to operate and can be widely applied to the design of thin film transistor devices with various materials and structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a design method for a thin film transistor device according to the present invention;

[0017] Figure 2 Schematic diagram of the flow of a design method for a thin film transistor device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0019] Based on an analysis of the current status of related research fields and using high-throughput integration and first-principles calculation methods, this paper proposes a design method for thin-film transistor devices. This method is simple to operate and can be widely applied to the design of thin-film transistor devices made of various materials and structures.

[0020] High-throughput integrated computing, in layman's terms, involves submitting a large number of computational tasks at once. Through element substitution, high-throughput screening, structural optimization, and related property calculations, it theoretically predicts potential new structures and formulations. The design of high-performance thin-film transistor devices integrates the selection of initial materials, component design and screening, device structure design and optimization, performance prediction, and feedback. This is then controlled through automated computing modules, enabling an automated design process for thin-film transistor devices, ultimately resulting in a thin-film transistor device with superior overall performance.

[0021] like Figure 1 As shown, the present invention discloses a design method for a thin film transistor device, comprising:

[0022] Calculate the characteristic parameters of the searched material;

[0023] Screening materials according to characteristic parameter thresholds to obtain first active layer materials;

[0024] Simulating the first active layer material as the active layer material in a thin film transistor device model to obtain device characteristics of the thin film transistor device;

[0025] Screening the first active layer material according to the device characteristic threshold to obtain the second active layer material;

[0026] Conducting experiments using the second active layer material as an active layer material of a thin film transistor device;

[0027] When the experimental results do not meet the preset requirements, another second active layer material is selected to conduct the experiment again until the experimental results meet the preset requirements and the design of the thin film transistor device is completed.

[0028] In some embodiments of the present invention, the characteristic parameters include at least one of energy band structure, band gap, Schottky barrier, work function, and intermediate phase.

[0029] In some embodiments of the present invention, the characteristic parameter threshold comprises at least one of a bandgap threshold, a Schottky barrier threshold, a work function threshold, or an intermediate phase threshold;

[0030] In some embodiments of the present invention, the band gap threshold is 0.5 to 3 eV;

[0031] In some embodiments of the present invention, the Schottky barrier threshold is 0.1 to 2 eV;

[0032] In some embodiments of the present invention, the work function threshold is 2.5 to 5.5 eV;

[0033] In some embodiments of the present invention, the intermediate phase threshold is 1 to 4.

[0034] In some embodiments of the present invention, the simulation step specifically includes simulating a transfer curve and an output curve of the thin film transistor device, and determining device characteristics of the thin film transistor device according to the transfer curve and the output curve.

[0035] In some embodiments of the present invention, the device characteristic includes at least one of a threshold voltage, a device mobility, a current switching ratio, or a subthreshold swing.

[0036] In some embodiments of the present invention, the device characteristic threshold comprises at least one of a threshold voltage threshold, a device mobility threshold, a current switching ratio threshold, or a subthreshold swing threshold;

[0037] In some embodiments of the present invention, the threshold voltage threshold is less than 0.5V;

[0038] In some embodiments of the present invention, the device mobility threshold is 1 to 1000 cm 2 / V / s;

[0039] In some embodiments of the present invention, the current switching ratio threshold is 10 3 to 10 8 ;

[0040] In some embodiments of the present invention, the subthreshold swing threshold is 10 to 300 mV / dec.

[0041] In some embodiments of the present invention, the step of selecting materials as the first active layer material according to the characteristic parameter threshold further includes storing the first active layer material in a first database;

[0042] In some embodiments of the present invention, data in the first database is automatically input and output via an automated control system;

[0043] In some embodiments of the present invention, the first active layer database includes the types of active layer materials and characteristic parameters of the materials.

[0044] In some embodiments of the present invention, the step of screening the first active layer material according to the device characteristic threshold to obtain the second active layer material further includes storing the second active layer material in a second database;

[0045] In some embodiments of the present invention, the second active layer database includes the type of active layer material, characteristic parameters of the material, and device characteristics obtained by simulating when the active layer material is used as a thin film transistor device;

[0046] In some embodiments of the present invention, data in the first database are automatically input and output through an automated control system.

[0047] In some embodiments of the present invention, the method used to calculate the characteristic parameters of the material includes a first-principles calculation method.

[0048] In some embodiments of the present invention, the step of using the second active layer material as the active layer material of the thin film transistor device for experimental purposes further includes selecting source, drain and electrode materials of the thin film transistor device.

[0049] The technical solution of the present invention is further described below by means of specific embodiments in combination with the accompanying drawings. It should be noted that the following specific embodiments are only for illustration and the protection scope of the present invention is not limited thereto.

[0050] See also Figure 2 This embodiment provides a method for designing a thin film transistor device, the method comprising the following steps:

[0051] Step 1: Using first-principles calculations combined with a high-throughput integrated automated control process, search for materials that may become thin-film transistor devices, primarily the active layer materials of thin-film transistors. First-principles calculations are used to calculate the band structure, band gap, Schottky barrier, work function, and intermediate phase of the active layer materials found.

[0052] The active layer materials searched include existing known active layer materials and active layer materials unknown in the prior art. Therefore, this method can predict active layer materials unknown in the prior art, thereby expanding the selection range of active layer materials.

[0053] Among them, all calculation result data will be automatically input and output through high-throughput integrated automation control systems (such as MatCloud, MaXFlow), and the calculation result data will be collected and stored; the high-throughput integrated automation control system is used to realize automatic input and output as well as data collection and storage. The high-energy integrated automation control system is mainly used for data submission. Its function is to adopt a one-time submission method for large quantities of calculation tasks. From the moment the user starts material calculation, it assists the user in generating recommended calculation parameters, automatically submitting the job, automatically monitoring the job status, automatically downloading the job results, automatically extracting the input for the next calculation, and generating the final job report, etc. A series of automated processes. In this way, the entire simulation calculation process can be realized fully automatically without human intervention. On the one hand, it can reduce manpower expenses, and on the other hand, it can avoid erroneous results caused by human extraction, thereby ensuring the correctness of the calculation result extraction.

[0054] Step 2: Screen out active layer materials with specific material characteristics from the calculation results as first active layer materials, analyze, classify and store the first active layer materials, and establish a first database; the first database contains band structure data, band gap data, Schottky barrier, work function, possible phase structure, etc. of the active layer materials.

[0055] Among them, in this embodiment, the active layer material with specific material characteristics refers to the active layer material that meets the characteristic parameter threshold requirements. Specifically, the active layer material that meets the characteristic parameter threshold requirements, for example, the active layer material with a band gap range of 0.5eV-3eV, a Schottky barrier of 0.1eV-2eV, a work function of 2.5eV-5.5eV and an intermediate phase of 1-4, can be one of the characteristic parameter thresholds that meets one or more characteristic parameter thresholds. The more types of characteristic parameter thresholds that the active layer material meets, the better the performance.

[0056] In this embodiment, all data obtained from theoretical calculations are stored, classified, and organized. In the classification and storage steps, different data types are classified into different databases: for example, database A stores classified band structure data, database B stores classified band gap data, database C stores classified Schottky barrier data, and so on.

[0057] Step 3: Based on the established first database, active layer materials with better performance are screened out by establishing a thin film transistor device model simulation method.

[0058] This step mainly combines the device model of the thin film transistor device and studies the transfer characteristics and output characteristics of the thin film transistor device constructed with different thin film transistor active layer materials in detail. The threshold voltage (V th ), device mobility, current switching ratio I on / I off , subthreshold swing (SS), and at the same time, the stability of the thin film transistor device (the device will not show obvious changes in characteristics after long-term operation) and uniformity must be considered, and finally the active layer material with superior comprehensive performance, that is, the second active layer material, is selected.

[0059] Among them, the threshold voltage V th The closer to 0, the better. In this embodiment, the preferred active layer material of the thin film transistor device selects the threshold voltage V th Less than 0.5V, in other embodiments the threshold voltage V thFor example, it can be less than 0.4V, 0.3V, 0.2V, 0.1V, etc.

[0060] The larger the device mobility, the better. In this embodiment, the preferred active layer material of the thin film transistor device has a device mobility of 1-1000 cm 2 / V / s In other embodiments, the device mobility can be, for example, 1 cm 2 / V / s, 10cm 2 / V / s、100cm 2 / V / s、200cm 2 / V / s、500cm 2 / V / s、800cm 2 / V / s、1000cm 2 / V / s, etc.

[0061] Among them, the current switching ratio of the thin film transistor device of the preferred active layer material in this embodiment is I on / I off The range is 10 3 -10 8 Among them, in I off The smaller the switch ratio, the better. on The larger the value, the faster the device works and the greater its ability to drive the load. off The smaller the current, the lower the power consumption of the device. In other embodiments, the current switching ratio can be, for example, 10 3 , 10 4 , 10 5 , 10 6 , 10 7 , 10 8 .

[0062] The smaller the subthreshold swing range, the better. In this embodiment, the preferred active layer material of the thin film transistor device has a subthreshold swing range of 10-300 mV / dec. In other embodiments, the subthreshold swing range may be, for example, 10 mV / dec, 12 mV / dec, 15 mV / dec, 18 mV / dec, 20 mV / dec, 30 mV / dec, 50 mV / dec, 80 mV / dec, 100 mV / dec, 150 mV / dec, 180 mV / dec, 200 mV / dec, 220 mV / dec, 250 mV / dec, 280 mV / dec, or 300 mV / dec.

[0063] The stability of a thin film transistor device can be demonstrated by the fact that the device does not show significant changes in characteristics when it operates for a long time (for example, the range value is 100 hours of continuous operation), indicating that the device has good stability.

[0064] Step 4: Using the screened second active layer material of the thin film transistor and selecting suitable source and drain electrode materials, a thin film transistor device is designed based on a specific transistor structure (such as a top gate structure or a bottom gate structure). Generally, the selection criteria for the source and drain electrodes are by comparing the work function of the active layer material and the electrode material and the Schottky barrier formed between the interfaces: the closer the work function of the active layer material and the electrode material, and the smaller the Schottky barrier at the interface formed between them, the better.

[0065] The source and drain electrodes may be composed of at least one of Pt, Au, Cu, Ag, Mo, etc.

[0066] Step 5: Fabricate the thin-film transistor device and verify its performance. Finally, adjust the design based on the feedback from the tested thin-film transistor device. If the experimental verification results show poor performance, return to screen other active layer materials until a thin-film transistor device with superior overall performance is obtained.

[0067] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for designing a thin film transistor device, comprising: Using first-principles calculations combined with a high-throughput integrated automated control process, searching for active layer materials, wherein the active layer materials include known active layer materials and unknown active layer materials; Calculating characteristic parameters of the known active layer materials and the unknown active layer materials that have been searched, wherein the characteristic parameters include at least one of an energy band structure, a band gap, a Schottky barrier, a work function, and an intermediate phase, and each of the characteristic parameters corresponds to a characteristic parameter threshold; Based on the characteristic parameters of the known active layer material and the unknown active layer material, screening a material that meets at least one characteristic parameter threshold from the known active layer material and the unknown active layer material to obtain a first active layer material; The first active layer material is used as the active layer material in the thin film transistor device model for simulation to obtain device characteristics of the thin film transistor device; Screening the first active layer material according to the device characteristic threshold to obtain the second active layer material; Conducting an experiment using the second active layer material as an active layer material of a thin film transistor device; When the experimental result does not meet the preset requirements, another second active layer material is selected to conduct the experiment again, and the design of the thin film transistor device is completed when the experimental result meets the preset requirements.

2. The design method according to claim 1, characterized in that: The characteristic parameter threshold comprises at least one of a band gap threshold, a Schottky barrier threshold, a work function threshold or an intermediate phase threshold; Wherein, the band gap threshold is 0.5 to 3 eV; Wherein, the Schottky barrier threshold is 0.1 to 2 eV; Wherein, the work function threshold is 2.5 to 5.5 eV; Wherein, the intermediate phase threshold is 1 to 4.

3. The design method according to claim 1, characterized in that: The simulation step specifically includes simulating a transfer curve and an output curve of the thin film transistor device, and determining the device characteristics of the thin film transistor device according to the transfer curve and the output curve.

4. The design method according to claim 1, characterized in that: The device characteristic includes at least one of a threshold voltage, a device mobility, a current switching ratio, or a subthreshold swing.

5. The design method according to claim 1, characterized in that: The device characteristic threshold comprises at least one of a threshold voltage threshold, a device mobility threshold, a current switching ratio threshold or a subthreshold swing threshold; Among them, the threshold voltage threshold is less than 0.5 V; Among them, the device mobility threshold is 1 to 1000 cm 2 / V / s; Among them, the current switching ratio threshold is 10 3 Up to 10 8 ; The subthreshold swing threshold is 10 to 300 mV / dec.

6. The design method according to claim 1, characterized in that: The step of selecting a material satisfying at least one characteristic parameter threshold from the known active layer materials and the unknown active layer materials to obtain the first active layer material further includes storing the first active layer material in a first active layer database; Wherein, the data in the first active layer database is automatically input and output via an automated control system; The first active layer database includes the types of active layer materials and characteristic parameters of the materials.

7. The design method according to claim 6, characterized in that: The step of screening the first active layer material according to the device characteristic threshold to obtain the second active layer material also includes storing the second active layer material in a second active layer database; Wherein, the second active layer database includes the type of active layer material, characteristic parameters of the material and device characteristics obtained by simulating when the active layer material is used as a thin film transistor device; Wherein, the data in the first active layer database are automatically input and output through an automatic control system.

8. The design method according to claim 1, characterized in that: The step of using the second active layer material as the active layer material of the thin film transistor device for the experiment also includes the selection of the source electrode, drain and electrode materials of the thin film transistor device.

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