A lithium-ion solid-state electrolyte gate dielectric modulated transistor and a preparation method thereof
By using lithium-ion solid electrolyte as the gate dielectric material in the transistor and preparing a stable thin film using magnetron sputtering technology, the problem of performance degradation of traditional transistors under extreme environments is solved, achieving stable electrical performance with low operating voltage and high switching ratio, making it suitable for portable electronic products.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CENT SOUTH UNIV
- Filing Date
- 2022-10-24
- Publication Date
- 2026-07-24
AI Technical Summary
Existing lithium-ion solid glass films exhibit performance degradation under extreme environments. Traditional transistors operate at high voltages, have high manufacturing costs, and their gate dielectric materials are unstable, making it difficult to meet the low operating voltage requirements of portable electronic products.
Using lithium-ion solid electrolyte as the gate dielectric material, a lithium-ion solid electrolyte thin film is prepared by sequentially setting a gate electrode, an insulating layer and an active layer on a substrate and using magnetron sputtering technology. The combination of a high dielectric constant gate dielectric and thinning to reduce the on-state voltage forms a stable double-layer characteristic.
It achieves low operating voltage, stable electrical performance and high switching ratio, adapts to high and low temperature environments, simplifies the preparation process, reduces costs, and is applicable to most semiconductor materials.
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Figure CN115763542B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of transistor technology, and particularly relates to a solid-state electrolyte gate dielectric control transistor and its fabrication method. Background Technology
[0002] In recent years, scientists in microelectronics, physics, chemistry, and materials science have devoted tremendous efforts to developing high-performance transistor devices. The gate dielectric, as a crucial structure in transistors, determines important properties such as the transistor's operating mode and voltage. However, the development of novel gate dielectric materials has received little attention. It is well known that transistor performance depends not only on the transistor type, the characteristics of the semiconductor material, and the transistor's size, but also significantly on the gate dielectric material. Different electronic products require different transistor performance standards. To meet the future demands of portable electronic products, such as simple electronic tags, easy-to-use displays, and portable sensors, transistors must have very low operating voltages (less than 5V), which is generally determined by the gate dielectric. For traditional devices using thermally oxidized oxides as gate dielectrics, due to very weak gate coupling, their operating voltages are generally greater than 10V. Therefore, it is essential to develop novel gate dielectrics to improve their gate capacitance per unit area and reduce manufacturing costs, thereby lowering the transistor's operating voltage. Methods to improve gate capacitance per unit area generally include using high-dielectric-constant gate dielectrics and reducing the gate dielectric thickness. Another novel approach is to use an electronically insulating and ionically conductive electrolyte as the gate dielectric, such as an electrolyte solution, ionic liquid, or polymer electrolyte. This type of electrolyte acts as an insulating layer mainly by utilizing the electric double layer effect during the operation of transistor devices. Currently, electric double layer thin film transistors are also a key research focus and hot topic.
[0003] The main characteristic of electric double-layer thin-film transistors (EVTs) is the use of an electrolyte as the gate insulating layer material. Electrolyte materials are insulators of electrons and holes, but excellent ionic conductors. Under the influence of the gate voltage, free ions in the electrolyte layer of the EDT migrate to both ends of the electrolyte layer according to their polarity, forming a tight electric double layer at the interface between the semiconductor channel and the electrolyte, or between the electrolyte and the gate electrode. This gate insulating layer electrolyte material with double-layer properties is the most important reason why EDTs can simulate synaptic behavior. Currently, the gate insulating layer materials used in EDTs are typically polyelectrolytes, ionic liquids, ionic gels, or solid electrolytes, with solid electrolytes being a key research focus. Existing lithium-ion solid-state glasses mainly use gel-like thin films as the gate dielectric, which significantly degrades performance in extreme environments. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a lithium-ion solid electrolyte gate dielectric control transistor and its preparation method.
[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:
[0006] A lithium-ion solid electrolyte gate dielectric control transistor comprises, from bottom to top, a substrate, a gate electrode, an insulating layer, and an active layer, wherein an active electrode and a drain electrode are disposed on the active layer, and the insulating layer is made of a lithium-ion solid electrolyte thin film.
[0007] Preferably, the lithium-ion solid electrolyte includes one or more of LAGP, LATP, LLTO, LiPON, LGPS, LSZTO, LSLZTO, LAGTP, LSTNO, LLNO, LSLTO and LZGO.
[0008] The preferred lithium-ion solid electrolyte of this application is more stable than other lithium-ion electrolytes, easier to manufacture, has higher ionic conductivity, and can withstand high and low temperatures.
[0009] Compared to other gel-gate dielectric transistors, which exhibit more stable properties, the lithium-ion solid electrolyte used in this patent also demonstrates better controllability under rapid temperature changes compared to other gel-gate dielectrics. See details... Figure 8 , Figure 9 The patented material can maintain relatively stable electrical properties at both high and low temperatures. Moreover, it has a simpler structure and is easier to manufacture compared to most other transistor devices. Currently, most mainstream semiconductor materials are compatible with lithium-ion solid gate dielectrics.
[0010] Preferably, the thickness of the insulating layer is 200–400 nm.
[0011] Preferably, the substrate material includes one or more of silicon wafer, silicon dioxide and glass; the gate electrode material includes one or more of Al, Au, Ag and Si; the thickness of the gate electrode is 50-300 nm; the active layer material includes one or more of In2O3, poly-3-hexylthiophene (P3HT) and 2,7-dioctyl[1]benzothiophene[3,2-b]benzothiophene (C8PTPT); the active layer thickness is 50 nm-1 μm; the source electrode and the drain electrode material includes one or more of Al, Au and Ag, the thickness of the source electrode and the drain electrode is 10-100 nm, and the spacing between the source electrode and the drain electrode is 50-150 μm.
[0012] The materials of each layer are selected based on the electrolyte chosen in this application, resulting in a transistor with a higher on / off ratio and a lower operating voltage.
[0013] Under the same technical concept, this application also provides a method for fabricating a lithium-ion solid electrolyte gate dielectric control transistor, comprising the following steps:
[0014] (1) Fabricate a gate electrode on a substrate;
[0015] (2) A lithium-ion solid electrolyte film is prepared on the gate electrode prepared in step (1) to obtain an insulating layer;
[0016] (3) An active layer is prepared on the insulating layer obtained in step (2);
[0017] (4) Prepare source and drain electrodes on the active layer prepared in step (3).
[0018] Preferably, the lithium-ion solid electrolyte film is prepared by magnetron sputtering, and the process parameters for magnetron sputtering are: argon-oxygen ratio of 40:0 to 30:10, sputtering power of 50 to 140 W, and sputtering temperature of 40 to 80 °C. This invention preferably controls the magnetron sputtering process parameters within the above range, which helps ensure the smooth progress of the sputtering process and thus obtains a lithium-ion solid electrolyte film with uniform elemental thickness. When a large number of transistors are fabricated on the same substrate, uniform thickness ensures that the device performance is not significantly different, which is beneficial to the transistor's operating performance.
[0019] Preferably, the preparation method of the source electrode and drain electrode in step (4) includes thermal evaporation or magnetron sputtering, wherein the vacuum degree of thermal evaporation is less than 3 × 10⁻⁶. -3 Pa.
[0020] Under the same technical concept, this application also provides a control method for a lithium-ion solid electrolyte gate dielectric control transistor, comprising the following steps:
[0021] Taking an n-channel bottom-gate lithium-ion solid electrolyte transistor as an example, under a positive gate voltage, due to the ionic polarization effect of the lithium-ion solid electrolyte, mobile cations and anions migrate to the interface between the channel electrolyte and the gate electrolyte, respectively, thereby inducing an equal number of electrons in the n-channel. Under the action of an applied source-drain voltage, electrons move within the channel, forming a current source leakage current, and the transistor is in the "ON" state.
[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0023] (1) This invention utilizes a lithium-ion solid electrolyte as the gate dielectric. This type of electrolyte has good ionic conductivity, making it suitable for most transistor devices. The resulting transistors have good operating performance, low operating voltage, and can withstand harsh operating environments. The lithium-ion solid electrolyte in this invention can provide a channel for electron flow in semiconductors, has a lower on-state voltage drop than other gate dielectrics, is stable, has a long shelf life, exhibits excellent operating performance, can withstand high and low temperatures, and has significant synaptic characteristics.
[0024] (2) The transistor of this application can be controlled by forming a double electric layer by lithium ions, and can be controlled by the gate dielectric without the need for a metal oxide layer, thus replacing the metal oxide layer.
[0025] (3) In this application, a lithium-ion solid electrolyte is magnetron sputtered onto a substrate in an all-solid form, and the solid lithium-ion material is made into a thin film by magnetron sputtering so that it is tightly connected to the semiconductor layer, thereby reducing the on-state voltage. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 This is a structural diagram of the lithium-ion solid electrolyte transistor prepared in this invention;
[0028] Figure 2 A process flow diagram for fabricating transistor devices according to the present invention;
[0029] Figure 3 , 4 A lithium-ion solid electrolyte LAGP (Li) prepared in Example 1 of this invention 1.5 Al 0.5 Ge 1.5 Scanning electron microscope image of (PO4)3);
[0030] Figure 5 This is a transfer curve diagram of the synaptic transistor prepared in Embodiment 1 of the present invention;
[0031] Figure 6 The diagram shows the transfer curve of the synaptic transistor prepared in Embodiment 2 of the present invention.
[0032] Figure 7 The diagram shows the transfer curve of the synaptic transistor prepared in Comparative Example 1 of this invention.
[0033] Figure 8The electrical characteristic curves of the device in Embodiment 1 of the present invention at low temperature are shown.
[0034] Figure 9 The electrical characteristic curves of the device in Embodiment 1 of the present invention at high temperature are shown. Detailed Implementation
[0035] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.
[0036] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.
[0037] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.
[0038] Example 1:
[0039] A lithium-ion solid electrolyte gate dielectric control transistor, the structure diagram of which is shown below. Figure 1 As shown, the synaptic transistor includes a substrate, a gate electrode, an insulating layer, and an active layer arranged sequentially from bottom to top. An active electrode and a drain electrode are disposed on the active layer, and the insulating layer is made of a lithium-ion solid electrolyte film.
[0040] The fabrication process flow diagram of a lithium-ion solid electrolyte gate dielectric controlled transistor is shown below. Figure 2 As shown, a gate electrode is fabricated on a substrate, then a lithium-ion solid electrolyte is magnetron sputtered onto the gate electrode to obtain an insulating layer. A semiconductor layer is then fabricated on the insulating layer, and finally, source and drain electrodes are fabricated on the semiconductor layer, thus obtaining a transistor. The specific fabrication steps are as follows:
[0041] (1) Wash the silicon substrate with acetone, alcohol and deionized water in sequence, and then dry it with nitrogen; the silicon substrate can be used directly as the gate here.
[0042] (2) LAGP(Li) is applied to the above silicon substrate. 1.5 Al 0.5 Ge 1.5 (PO4)3) An insulating layer with a thickness of 300 nm was prepared by magnetron sputtering.
[0043] (3) In2O3 was magnetron sputtered onto the above insulating layer to obtain a 30nm active layer;
[0044] (4) On the above-mentioned active layer, a thermal vacuum evaporation method is used to control the vacuum level to be less than 3×10. -3 Pa, using Al as raw material, is used to fabricate source and drain electrodes, each with a thickness of 50 nm, thus obtaining a transistor.
[0045] The lithium-ion solid electrolyte LAGP (Li) prepared in step (2) 1.5 Al 0.5 Ge 1.5 Scanning electron microscope image of (PO4)3) as follows Figure 3 , 4 As shown, the electrolyte film has a uniform elemental thickness.
[0046] The transfer curve performance of the transistor prepared in this embodiment was tested, and the results are as follows: Figure 5 As shown in the figure, compared with the comparative example, it can be seen that the present invention, by using lithium-ion solid electrolyte as the gate dielectric layer of the synaptic transistor device, has prepared a transistor device with lower operating voltage, larger feedback window, better performance, and adaptability to most extreme environments.
[0047] The transistors fabricated in this embodiment were tested for their electrical characteristics at high and low temperatures, and the results are as follows: Figure 8 , 9 As shown, the material of this patent can maintain relatively stable electrical properties at both high and low temperatures. Moreover, it has a simpler structure and is easier to manufacture compared to most other transistor devices. Currently, most mainstream semiconductor materials are compatible with lithium-ion solid gate dielectrics.
[0048] Example 2:
[0049] A lithium-ion solid electrolyte gate dielectric control transistor, the structure diagram of which is shown below. Figure 1 As shown, the synaptic transistor includes a substrate, a gate electrode, an insulating layer, and an active layer arranged sequentially from bottom to top. An active electrode and a drain electrode are disposed on the active layer, and the insulating layer is made of a lithium-ion solid electrolyte film.
[0050] The fabrication process flow diagram of a lithium-ion solid electrolyte gate dielectric controlled transistor is shown below. Figure 2 As shown, a gate electrode is fabricated on a substrate, then a lithium-ion solid electrolyte is magnetron sputtered onto the gate electrode to obtain an insulating layer. A semiconductor layer is then fabricated on the insulating layer, and finally, source and drain electrodes are fabricated on the semiconductor layer, thus obtaining a transistor. The specific fabrication steps are as follows:
[0051] (1) Wash the silicon substrate with acetone, alcohol and deionized water in sequence, and then dry it with nitrogen. The silicon substrate can be used directly as the gate here.
[0052] (2) LAGP(Li) is applied to the aforementioned silicon bottom gate electrode.1.5 Al 0.5 Ge 1.5 (PO4)3) An insulating layer with a thickness of 300 nm was obtained by magnetron sputtering.
[0053] (3) An active layer of about 50 nm was prepared by vacuum thermal evaporation of a layer of 2,7-dioctyl[1]benzothiophene[3,2-b]benzothiophene (C8PTPT) on the above insulating layer.
[0054] (4) On the above-mentioned active layer, a thermal vacuum evaporation method is used to control the vacuum level to be less than 3×10. -3 Pa, using Al as raw material, is used to fabricate source and drain electrodes, each with a thickness of 50 nm, thus obtaining a transistor.
[0055] The transfer curve performance of the transistor prepared in this embodiment was tested, and the results are as follows: Figure 6 As shown in the figure, by using lithium-ion solid electrolyte as the gate dielectric layer of the synaptic transistor device, the present invention has prepared a transistor device with excellent performance that can adapt to most extreme environments.
[0056] Comparative Example 1
[0057] A silicon dioxide gate dielectric control transistor, the structure diagram of which is shown below. Figure 1 As shown, the synaptic transistor includes, from bottom to top, a substrate, a gate electrode, an insulating layer, and an active layer. An active electrode and a drain electrode are disposed on the active layer. The insulating layer is made of SiO2. Here, a silicon wafer with SiO2 deposited on its surface is used as the substrate.
[0058] (1) Wash the silicon substrate with acetone, alcohol and deionized water in sequence, and then dry it with nitrogen. Here, the silicon substrate is used directly as the gate.
[0059] (2) In2O3 was magnetron sputtered onto the above SiO2 insulating layer to obtain an active layer of about 30 nm;
[0060] (3) On the above-mentioned active layer, a thermal vacuum evaporation method is used to control the vacuum level to be less than 3×10. -3 Pa, using Al as raw material, is used to fabricate source and drain electrodes, each with a thickness of 50 nm, thus obtaining a transistor.
[0061] The transfer curve performance of the transistor prepared in this comparative example was tested, and the results are as follows: Figure 7 As shown, the comparative example uses silicon dioxide as the insulating layer. Devices with silicon dioxide as the insulating layer have a higher operating voltage, a smaller feedback window, and no storage.
Claims
1. A lithium-ion solid electrolyte gate dielectric control transistor, characterized in that, The substrate, gate electrode, insulating layer, and active layer are arranged sequentially from bottom to top. An active electrode and a drain electrode are disposed on the active layer. The insulating layer is made of a lithium-ion solid electrolyte film. The lithium-ion solid electrolyte is LAGP.
2. The lithium-ion solid electrolyte gate dielectric control transistor as described in claim 1, characterized in that, The thickness of the insulating layer is 200–400 nm.
3. The lithium-ion solid electrolyte gate dielectric control transistor as described in claim 1, characterized in that, The substrate material includes one or more of silicon wafers, silicon dioxide, and glass; the gate electrode material includes one or more of Al, Au, Ag, and Si; the thickness of the gate electrode is 50–300 nm; the active layer material includes In₂O₃, polyethylene, and polysilicon. 3-Hexylthiophene and 2,7 Dioctyl[1]benzothiophene[3,2] b] One or more of benzothiophene; the thickness of the active layer is 50 nm to 1 μm; the material of the source electrode and the drain electrode includes one or more of Al, Au and Ag, and the thickness of the source electrode and the drain electrode is 10 to 100 nm.
4. A method for fabricating a lithium-ion solid electrolyte gate dielectric control transistor according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Fabricate a gate electrode on a substrate; (2) A lithium-ion solid electrolyte film is prepared on the gate electrode prepared in step (1) to obtain an insulating layer; (3) An active layer is prepared on the insulating layer obtained in step (2); (4) Prepare source and drain electrodes on the active layer prepared in step (3).
5. The method for fabricating a lithium-ion solid electrolyte gate dielectric control transistor as described in claim 4, characterized in that, Before fabricating the gate electrode on the substrate in step (1), the substrate is washed and dried in sequence. The washing is performed by washing with acetone, alcohol and deionized water in sequence; the drying is performed by blowing with nitrogen gas; the gate electrode is fabricated by vacuum evaporation or sputtering.
6. The method for fabricating a lithium-ion solid electrolyte gate dielectric control transistor as described in claim 5, characterized in that, The lithium-ion solid electrolyte film in step (2) is prepared by magnetron sputtering. The process parameters of magnetron sputtering are: argon-oxygen ratio of 40:0 to 30:10, sputtering power of 50 to 140 W, and sputtering temperature of 40 to 80 °C.
7. The method for fabricating a lithium-ion solid electrolyte gate dielectric control transistor as described in claim 4, characterized in that, The preparation method of the source electrode and drain electrode in step (4) includes thermal evaporation or magnetron sputtering, wherein the vacuum degree of thermal evaporation is less than 3 × 10⁻⁶. 3 Pa.
8. A control method for a lithium-ion solid electrolyte gate dielectric control transistor according to any one of claims 1-3, characterized in that, With n Taking a bottom-gate lithium-ion solid electrolyte transistor with a channel as an example, under the action of a positive gate voltage, due to the ionic polarization effect of the lithium-ion solid electrolyte, mobile cations and anions migrate to the interface between the channel electrolyte and the gate electrolyte, respectively, thereby achieving n The channel induces an equal number of electrons with charge. Under the action of the applied source-drain voltage, the electrons move in the channel, thereby forming a current source leakage current, and the transistor is in the "ON" state.