Rare earth metal fluoride superionic conductor dielectric thin films and their preparation methods

Abstract

This invention discloses a rare-earth metal fluoride superionic conductor dielectric film and its preparation method. The dielectric film is prepared from a rare-earth metal fluoride superionic conductor using a thermal evaporation method. The rare-earth metal fluoride superionic conductor is selected from scandium fluoride, yttrium fluoride, lanthanum fluoride, cerium fluoride, neodymium fluoride, samarium fluoride, europium fluoride, gadolinium fluoride, holmium fluoride, erbium fluoride, ytterbium fluoride, praseodymium fluoride, promethium fluoride, terbium fluoride, dysprosium fluoride, thulium fluoride, and lutetium fluoride. This invention utilizes thermal evaporation to heat and evaporate the rare-earth metal fluoride source material into a gaseous state within an evaporation system. The gaseous fluoride directly adheres to a substrate placed above the source material and recrystallizes. This allows for controllable thickness and defect number of the rare-earth metal fluoride, resulting in high integration. Therefore, rare-earth metal fluoride superionic conductor dielectric materials show great potential in the design and manufacture of novel functional devices.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor materials technology, specifically relating to a rare earth metal fluoride superionic conductor dielectric thin film and its preparation method. Background Technology

[0002] Dielectric materials are among the core materials used in condensed matter physics and advanced electronic devices. As the miniaturization of traditional semiconductor devices approaches its physical limits, a crucial solution to overcome the adverse effects of short-channel effects is to find dielectric materials with stronger control over channel materials. In condensed matter physics research, the manipulation of various strongly correlated electronic phenomena also requires the development of dielectric materials with greater capacitive coupling. Traditional low-dielectric-constant SiO2 dielectric materials and subsequently developed high-dielectric-constant dielectric materials such as HfO2 and ZrO2 often face severe gate leakage problems due to their dielectric breakdown limits, and are gradually failing to meet the field-effect control requirements of electronic states in micro-semiconductor devices or strongly correlated electronic systems. Although researchers have successively developed novel dielectrics with larger capacitive coupling, such as SrTiO3 single-crystal thin-film oxide dielectrics with ultra-high dielectric constants and organic electrolyte materials, these new dielectrics still have significant problems in practical applications. For example, SrTiO3 single-crystal thin-film oxide dielectrics require transfer to a target substrate or material surface and are not suitable for wafer-level fabrication; while organic electrolyte materials, which mostly exist in liquid or gel form, are difficult to be compatible with traditional semiconductor photolithography processes. In addition, liquid electrolytes also have electrochemical mechanisms that seriously affect the stability and reproducibility of devices. Therefore, it is crucial to find dielectric materials that possess large coupling capacitance, wide bandgap, stable existence in solid-state form, compatibility with traditional semiconductor device processes, and the ability to be grown on a large scale.

[0003] Due to the superionic properties of fluorides, fluoride ions can move rapidly within the crystal and form an electric double-layer effect under an electric field. Therefore, this structural characteristic is highly suitable for use as a solid ionic dielectric in various electronic devices. However, previous studies on the properties of fluorides were based on their powder or solid solution forms, which cannot be directly applied to the fabrication of electronic devices. Therefore, this invention proposes to directly prepare fluoride thin films from fluoride powders. Summary of the Invention

[0004] One objective of this invention is to provide a superionic conductor dielectric film, obtained from rare-earth metal fluoride superionic conductors; the conductivity of the superionic conductor dielectric film is 10. -2 -10 -5 S / cm, low-frequency capacitance (0.01Hz) is 1-25μF / cm 2 High-frequency capacitor (10 6(Hz) is 0.02-0.2 μF / cm 2 Leakage current density less than 10 -5 A / cm 2 The root mean square surface roughness is less than 1 nm, and the fluorine vacancy content is 0.01-15%.

[0005] Furthermore, the rare earth metal fluoride superionic conductor is selected from scandium fluoride, yttrium fluoride, lanthanum fluoride, cerium fluoride, neodymium fluoride, samarium fluoride, europium fluoride, gadolinium fluoride, holmium fluoride, erbium fluoride, ytterbium fluoride, praseodymium fluoride, promethium fluoride, terbium fluoride, dysprosium fluoride, thulium fluoride, and lutetium fluoride.

[0006] The second objective of this invention is to provide a method for preparing the above-mentioned superionic conductor dielectric film, wherein the dielectric film is prepared by thermal evaporation.

[0007] Furthermore, the preparation method involves: first, grinding the rare earth metal fluoride superionic conductor, then placing it on the heating column of a thermal evaporation system, until the system vacuum reaches 10... -5 Evaporation begins when Pa is below a certain level, with rare earth metal fluorides... The evaporation rate is adjusted to deposit on the substrate surface until a thickness of 10-20 nm is achieved. Until the target thickness is achieved, the temperature of the substrate is controlled at 200-600K during the vapor deposition process.

[0008] Furthermore, the rare earth metal fluoride superionic conductor is ground to a particle size of less than 200 mesh.

[0009] Furthermore, the substrate is made of SiO2 / Si, silicon, germanium, mica, sapphire, ruby, indium phosphide, indium arsenide, gallium phosphide, gallium nitride, strontium titanate, zirconium oxide, silicon carbide, or quartz glass.

[0010] In the thermal growth of rare-earth metal fluoride superionic conductor dielectric films, a slow evaporation rate is initially selected to obtain films with high density. In one embodiment of the present invention, a method is employed... The evaporation rate can be increased once the film thickness reaches a certain value, such as 10 nm, in order to reduce the total evaporation time. Simultaneously, the system's vacuum level needs to be controlled. Theoretically, the better the system vacuum level, the denser and higher the quality of the deposited film. For example, 10 -5 High vacuum on the order of Pa. In addition, in order to form more fluorine vacancies and improve the ionic conductivity of the fluoride film, this invention is designed to use a relatively low substrate temperature, such as 200-600K.

[0011] A third objective of this invention is to provide the application of the aforementioned superionic conductor dielectric thin film in the fabrication of electronic devices. Preferably, the electronic device is a semiconductor device, an optoelectronic device, a magneto-optical device, or a non-volatile magnetic storage device.

[0012] The rare-earth metal fluoride superionic conductor thin film provided by this invention can be applied to various semiconductor devices (such as field-effect transistors, inverters, logic gates, etc.) due to its excellent dielectric properties. At the same time, LaF3 with special optical properties can be used to prepare optical upconversion materials or antireflection coating materials. Ferromagnetic fluorides (such as NiF3, YbF3 and GdF3) can be used in magneto-optical devices, or magnetic fluoride thin films can be used to induce non-magnetic materials to generate magnetism.

[0013] The fourth objective of this invention is to provide a semiconductor device comprising the aforementioned superionic conductor dielectric thin film; the semiconductor device being a field-effect transistor, an inverter circuit, or a logic gate circuit.

[0014] This invention employs thermal evaporation to deposit rare-earth metal fluoride superionic conductor dielectric films. Thermal evaporation is a simple, low-cost, and large-scale film growth method with controllable film quality and thickness. Because the metal cation lattice framework in rare-earth metal fluoride superionic conductors allows fluoride ions with small ionic radii to move freely within the crystal, and rare-earth metal fluorides possess large band gaps and excellent insulation properties, this helps suppress leakage current through the fluoride film dielectric. Through thermal evaporation, the rare-earth metal fluoride source material is heated and evaporated into a gaseous state in the evaporation system. The gaseous fluoride directly adheres to the substrate placed above the source material and recrystallizes, thus enabling controllable thickness and defect number of the rare-earth metal fluoride, and exhibiting high integration. This demonstrates the great potential of superionic rare-earth metal fluoride dielectric materials in the design and manufacture of novel functional devices. Attached Figure Description

[0015] Figure 1 In the image, (a) is a photograph of the rare earth metal fluoride superion conductor source material particles, and (b) is a schematic diagram of the thermal evaporation principle.

[0016] Figure 2 The AFM characterization results of the NdF3 thin film are shown in (a) and (b) respectively. (c) is an optical image of the NdF3 thin film on an InP(100) substrate. (d) is the surface roughness result of the NdF3 thin film obtained by AFM. (c) is the corresponding line profile of the sample along the green line in (b).

[0017] Figure 3The following are the TEM characterization results of the LaF3 superionic conductor film: (a) cross-sectional TEM image of the LaF3 superionic conductor film; (b) Pt element distribution during TEM testing; (c) lanthanum element distribution in the LaF3 superionic conductor film; (d) fluorine element distribution in the LaF3 superionic conductor film; (e) oxygen element distribution in the substrate; and (f) silicon element distribution in the substrate.

[0018] Figure 4 In the image, (a) and (b) are elemental distribution scans of CeF3 superionic conductor films, and (c) and (d) are elemental distribution scans of NdF3 superionic conductor films.

[0019] Figure 5 This is a geometric schematic diagram for capacitance testing of a fluoride superionic conductor dielectric film.

[0020] Figure 6 Capacitance detection curves for 11 rare earth metal fluoride superionic conductor thin films.

[0021] Figure 7 The leakage current density test results are for the LaF3 superionic conductor thin film.

[0022] Figure 8 The results show the temperature-dependent ionic conductivity comparison of LaF3 superionic conductor films and other lithium-ion electrolytes.

[0023] Figure 9 In the figure, (a) is a schematic diagram of the bottom gate MoS2 field-effect transistor based on NdF3 thin film superionic conductor gate dielectric, and (b) is the transfer characteristic curve under different source-drain voltages. Detailed Implementation

[0024] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0025] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0026] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0027] The thermal evaporation system used in the following embodiments is the VZZ-300 high vacuum thermal evaporation system from Beijing MicroNano Vacuum Co., Ltd. Other high vacuum thermal evaporation systems can also be used, as long as the vacuum regulation of the thermal evaporation process can be controlled.

[0028] The rare earth metal fluorides used in this invention are sourced from the following sources:

[0029] Table 1

[0030] Fluorides Company (Country) purity(%) <![CDATA[Scandium fluoride (ScF3)]]> Shanghai Maclean Biotechnology Co., Ltd. (China) 99.99 <![CDATA[Yttrium fluoride (YF3)]]> Beijing Zhongjin Research New Materials Technology Co., Ltd. (China) 99.99 <![CDATA[Lanthanum fluoride (LaF3)]]> Shanghai Aladdin Biochemical Technology Co., Ltd. (China) 99.99 <![CDATA[Cerium fluoride (CeF3)]]> Shanghai Aladdin Biochemical Technology Co., Ltd. (China) 99.99 <![CDATA[Neodymium fluoride (NdF3)]]> Shanghai Aladdin Biochemical Technology Co., Ltd. (China) AR <![CDATA[Samarium fluoride (SmF3)]]> Shanghai Aladdin Biochemical Technology Co., Ltd. (China) 99.9 <![CDATA[Europium fluoride (EuF3)]]> West Asia Reagent Co., Ltd. (China) 99.5 <![CDATA[Gadolinium fluoride (GdF3)]]> West Asia Reagent Co., Ltd. (China) 99.9 <![CDATA[Holmium fluoride (HoF3)]]> West Asia Reagent Co., Ltd. (China) 99.99 <![CDATA[Erbium fluoride (ErF3)]]> West Asia Reagent Co., Ltd. (China) 99.9 <![CDATA[Ytterbium fluoride (YbF3)]]> Shanghai Maclean Biotechnology Co., Ltd. (China) 99.99

[0031] Example 1

[0032] I. The preparation process of fluoride superionic conductor thin films is as follows:

[0033] 1. Pressing of rare earth metal fluoride powders

[0034] First, the fluoride powder or lumps are ground into an extremely fine powder with a particle size of less than 200 mesh. The powder is then loaded into a stainless steel mold with a diameter of 10 mm for pressing. In this embodiment, depending on the size of the selected tungsten boat, the fluoride powder is pressed into a column shape with a diameter of 10 mm and a length of 10 mm.

[0035] 2. Thermal growth preparation of rare earth metal fluoride superionic conductor thin films

[0036] The compressed columnar fluoride material is placed in a tungsten boat, which is then transferred to the heating column of the thermal evaporation system and secured. Simultaneously, the SiO2 / Si substrate to be deposited is adhered using high-temperature resistant yellow tape, and a substrate baffle is placed directly beneath the substrate to seal the cavity. The pneumatic valve between the vacuum pump and the evaporation system is opened, followed by the mechanical pump to obtain a rough vacuum. When the system vacuum level is better than 5 Pa, the molecular pump is activated for evacuation until the system reaches 10 Pa. -5 High vacuum in the Pa range.

[0037] Turn on the water cooling system of the substrate. Increase the current flowing through the tungsten boat. When the heating temperature exceeds the melting point of the fluoride, fluoride molecules begin to deposit on the pre-placed substrate to form a fluoride film. Monitor the thickness of the rare earth metal fluoride film on the SiO2 / Si substrate surface using a crystal oscillator film thickness gauge. During the evaporation process, first allow the fluoride material to... The fluoride material is exhaled at a certain rate to remove surface-adsorbed impurities. When the exhaled thickness reaches 10 nm or more, the baffle between the fluoride material and the substrate is opened. Then, the current flowing through the tungsten boat is reduced, and the reading of the crystal oscillator film thickness gauge is observed to maintain the current. The rate of thermal evaporation, maintaining The evaporation rate was increased until the thickness reached over 10 nm; finally, the current flowing through the tungsten boat was increased, and the evaporation rate was increased further by observing the reading of the crystal oscillator film thickness gauge. A faster rate of thermal evaporation, maintaining The rate continues until the target thickness of 200nm is reached.

[0038] The crystal structure, thermal evaporation current, background vacuum before vapor deposition, and worst vacuum during vapor deposition of different fluorides are shown in Table 2.

[0039] Table 2

[0040]

[0041] II. Basic Characterization of Rare Earth Metal Fluoride Superionic Conductor Thin Films

[0042] To evaluate the compatibility of rare-earth metal fluoride superionic conductor films with III-V semiconductors, rare-earth metal fluoride films were deposited on InP(100) substrates using a thermal evaporation method and characterized by atomic force microscopy (AFM). Figure 2 As shown, taking NdF3 as an example, the fluoride film is highly uniform and flat on the InP(100) substrate, with a root mean square surface roughness of less than 0.61 nm. This result indicates that rare earth metal fluoride film dielectrics are very similar to widely used oxide dielectrics (such as HfO2 or Al2O3) and can be compatible with SiO2 / Si substrates or III-V semiconductor substrates for scalable electronic device applications. Figure 3 This is a transmission electron microscope (TEM) image of a representative LaF3 thin film, showing the distribution of each element.

[0043] To further confirm the actual chemical element ratio of cations and anions in rare-earth metal fluoride superionic conductor films, energy-dispersive X-ray spectroscopy (EDX) was performed to characterize the rare-earth metal fluorides. The working principle of EDX is to identify the different elements in the test sample by distinguishing the characteristic X-rays emitted by different elements. The chemical element ratios of rare-earth metal fluoride (CeF3 and NdF3) films were characterized by EDX testing, and the results are as follows: Figure 4 As shown in Table 3, the specific chemical element ratios of CeF3 and NdF3 films were obtained through data analysis. It can be seen that the actual proportion of fluoride ions in the rare earth metal fluoride films is lower than the 3:1 ratio in the chemical formula. This test result indicates the presence of a large number of fluoride ion vacancies in the rare earth metal fluoride films. It is precisely the presence of these fluoride ion vacancies that facilitates the rapid migration of fluoride ions within the fluoride lattice framework, thereby giving it high ionic conductivity.

[0044] Table 3

[0045] Sample 1 Sample 2 Sample 3 Sample 4 average Vacancy concentration (%) <![CDATA[NdF3]]> 25.4:74.6 23.6:76.4 26.5:73.5 25.5:74.5 1:2.96 1.3 <![CDATA[CeF3]]> 25.4:74.6 25.3:74.7 26:74 25.5:74.5 1:2.91 3.0

[0046] like Figure 5As shown, the capacitance characteristics of the fluoride were tested using a parallel-plate capacitor structure with a silicon substrate having a 300nm oxide layer. First, the pattern of the lower electrode was pre-fabricated on the silicon substrate using photolithography. Then, a metal electrode was deposited using an electron beam evaporation system to serve as the lower electrode of the parallel-plate capacitor. Next, a metal fluoride solid solution film was deposited on the pre-fabricated electrode substrate using a thermal evaporation system. Finally, the pattern of the upper electrode was pre-fabricated on the metal fluoride film using photolithography, and a metal electrode was deposited using an electron beam evaporation system to serve as the upper electrode of the parallel-plate capacitor. Electrochemical impedance spectroscopy (EIS) measurements were performed on an electrochemical workstation (Zahner Zennium Pro). Based on the parallel-plate capacitor geometry (metal electrode / fluoride / metal electrode with a 200nm fluoride film), a 20mV AC voltage was applied as a perturbation signal, and EIS measurements were performed within a frequency range (f) from 0.01Hz to 1MHz to obtain the frequency-dependent impedance Z and phase angle θ. The capacitance C per unit area of ​​a fluoride film is calculated using the following formula:

[0047] C = 1 / 2πfZ″S.

[0048] Where f is the frequency, Z″ is the imaginary part of the impedance, and S is the area of ​​the parallel-plate capacitor. Temperature-dependent EIS measurements are performed in a cryogenic system under vacuum conditions.

[0049] To further investigate the capacitive coupling performance of these 11 rare-earth metal fluoride superionic conductors, frequency-dependent capacitances were measured at room temperature, with the aim of identifying suitable dielectric materials for various electronic devices. Figure 6 The figure shows the capacitive characteristics of a series of rare earth metal fluoride films. As can be seen from the figure, the capacitive coupling characteristics of rare earth lanthanide films are very high, with the highest double-layer capacitance reaching 20 μF / cm. 2 Examples of rare earth metal fluoride thin films include CeF3, NdF3, SmF3, and LaF3. Therefore, the rare earth metal fluoride thin films of this invention have great potential as dielectric layer materials for field-effect transistors.

[0050] To evaluate the insulating properties of the fluoride thin-film superionic conductor dielectric, the leakage current density as a function of the gate voltage was measured. For example... Figure 7 As shown, even at a gate voltage of 12V, the leakage current density of the LaF3 film is as low as 10. -5 A / cm 2 This is three orders of magnitude lower than the low power limit of CMOS devices, indicating that the rare earth metal fluoride film of the present invention has excellent insulation properties. Such excellent electrical insulation makes superionic rare earth metal fluorides a very competitive dielectric material candidate for building high-performance electronic devices.

[0051] The table below shows the test results of the relevant properties of the rare earth metal fluoride superionic conductor thin film prepared in this embodiment:

[0052] Table 4

[0053]

[0054] As mentioned above, the excellent dielectric properties of rare-earth metal fluoride superionic conductors are due to the superionic nature of fluoride ions. Therefore, to better understand the superionic properties of fluoride ions, it is necessary to further experimentally determine the fluoride ion conductivity (σ). DC ) and its evolution with temperature. Figure 8 The temperature-dependent ionic conductivity of LaF3 films and other widely used lithium-ion electrolytes (such as ionic liquids and lithium-based solid electrolytes) is shown. It can be seen that the ionic conductivity of LaF3 films (10⁻⁶) is... -3 The conductivity (S / cm) is comparable to that of typical lithium superionic conductor materials, such as LiPON, Li₂S-P₂S₅, and Li 3.6 Si 0.6 P 0.4 O4 directly confirmed the superionic conductor properties of the LaF3 thin film, a superionic rare earth metal fluoride.

[0055] Example 2

[0056] Based on the excellent dielectric properties of the aforementioned rare-earth metal fluoride superionic conductor thin film, the advantages of rare-earth metal fluoride as a novel dielectric material in electronic devices can be further illustrated by constructing a single gate dielectric field-effect transistor based on a rare-earth metal fluoride thin film. For example... Figure 9 As shown in (a), the overall configuration of the two-dimensional semiconductor field-effect transistor with rare earth metal fluoride dielectric film adopts a bottom gate structure. A rare earth metal fluoride film is deposited on a silicon substrate with a 300nm oxide layer as the dielectric layer material of the field-effect transistor, and the channel material is an n-type doped two-dimensional semiconductor material MoS2.

[0057] The fabrication process of a field-effect transistor is as follows:

[0058] (1) Substrate cleaning: First, put the cut SiO2 / Si substrate into a mixed solution of acetone, ethanol and isopropanol, and clean it in an ultrasonic cleaner for 3-5 minutes to remove impurities attached to the surface. Then rinse it with isopropanol solution and treat the surface of the SiO2 / Si substrate with oxygen plasma to remove the residual organic solution, so that it has a clean surface.

[0059] (2) Preparation of bottom gate electrode: The bottom gate electrode pattern is pre-formed on the SiO2 / Si substrate by photolithography. Titanium gold electrodes (the thickness of the titanium gold metal electrodes is 3 / 9nm) are deposited by electron beam evaporation as the bottom gate. Then, the metal electrodes are stripped in acetone solution and rinsed with isopropanol to obtain a substrate with the bottom gate.

[0060] (3) A rare earth metal fluoride film is thermally grown on a SiO2 / Si substrate with a pre-set bottom gate electrode pattern.

[0061] (4) Preparation of two-dimensional channel material: The mechanical peeling method is adopted. First, the layered sheet of two-dimensional material is mechanically peeled off from the bulk MoS2 crystal with tape, and then polydimethylsiloxane (PDMS) is used for further peeling. The sample thickness is determined by optical photographs and suitable thin-layer two-dimensional material samples are found. Then, the MoS2 material sheet is transferred from PDMS to the surface of the metal fluoride film obtained in the third step by dry transfer.

[0062] (5) Deposition of source and drain metal electrodes: Polymethyl methacrylate (PMMA) was spin-coated onto the substrate surface of the transferred sample. Electrode patterns were formed on the MoS2 sample using photolithography. After development, metal electrodes (Ti / Au, 6+45nm) were deposited by electron beam evaporation. Finally, the metal electrodes were stripped in acetone solution and rinsed with isopropanol to obtain the final two-dimensional field-effect transistor device. To improve the interfacial contact resistance of the metal semiconductor, an annealing treatment was performed at 200°C under argon-hydrogen gas (95% Ar and 5% H2) for two hours.

[0063] Device testing method: The above-mentioned field-effect transistors were tested for device performance at room temperature. The source-drain voltage and gate voltage were applied by a probe station based on a Keysight 4200 semiconductor analyzer, and the source-drain current and gate leakage current were measured simultaneously.

[0064] Figure 9 Image (a) shows a schematic diagram of a bottom-gate MoS2 field-effect transistor based on a rare-earth metal fluoride superionic conductor (NdF3) thin-film gate dielectric. The upper right inset shows an optical photograph of the device. Figure 9 As can be seen from the transfer characteristic curve in (b), the MoS2 channel material exhibits n-type doping, and it can be concluded that the MoS2 bottom-gate field-effect transistor based on the NdF3 gate dielectric exhibits an ultra-high on / off current ratio (~10). 8 ), and an ultra-low subthreshold swing close to the thermodynamic limit (65mV dec) -1 ).

Claims

1. A superionic conductor dielectric thin film, characterized in that, Obtained from rare-earth metal fluoride superionic conductors; the dielectric film has a conductivity of 10. -5 -10 -2 S / cm, low-frequency capacitance is 1-25 μF / cm 2 The high-frequency capacitance is 0.02-0.2 μF / cm. 2 Leakage current density less than 10 −5 A / cm 2 The surface roughness root mean square is less than 1 nm, and the fluorine vacancy content is 0.01-15%. The superionic conductor dielectric film is prepared by thermal evaporation. The preparation process is as follows: first, the rare earth metal fluoride superionic conductor is ground, and then it is placed on the heating column of the thermal evaporation system. When the system vacuum degree reaches 10... −5 When the pressure is below Pa, evaporation begins. Rare earth metal fluoride superionic conductors are evaporated and deposited on the substrate surface at a rate of 0.2-0.4 Å / s until the thickness reaches 10-20 nm. The rate is then adjusted to 0.8-1 Å / s until the target thickness is reached.

2. The superionic conductor dielectric thin film according to claim 1, characterized in that, The rare earth metal fluoride superionic conductor is selected from scandium fluoride, yttrium fluoride, lanthanum fluoride, cerium fluoride, neodymium fluoride, samarium fluoride, europium fluoride, gadolinium fluoride, holmium fluoride, erbium fluoride, ytterbium fluoride, praseodymium fluoride, promethium fluoride, terbium fluoride, dysprosium fluoride, thulium fluoride, and lutetium fluoride.

3. The method for preparing the superionic conductor dielectric thin film according to claim 1 or 2, characterized in that, The dielectric film is prepared by thermal evaporation. The preparation process is as follows: first, the rare earth metal fluoride superionic conductor is ground, and then it is placed on the heating column of the thermal evaporation system. When the system vacuum degree reaches 10... −5 Evaporation begins when the dielectric strength is below Pa. Rare earth metal fluoride superionic conductors are deposited on the substrate surface at a rate of 0.2–0.4 Å / s until a thickness of 10–20 nm is achieved. The rate is then adjusted to 0.8–1 Å / s until the target thickness is reached. The resulting dielectric film has a conductivity of 10⁻⁶. -5 -10 -2 S / cm, low-frequency capacitance is 1-25 μF / cm 2 The high-frequency capacitance is 0.02-0.2 μF / cm. 2 Leakage current density less than 10 −5 A / cm 2 The surface roughness root mean square is less than 1 nm, and the fluorine vacancy content is 0.01-15%.

4. The preparation method according to claim 3, characterized in that, The temperature of the substrate is controlled at 200-600 K during the vapor deposition process.

5. The preparation method according to claim 3, characterized in that, The rare earth metal fluoride superionic conductor is ground to a particle size of less than 200 mesh.

6. The preparation method according to claim 3, characterized in that, The substrate is made of SiO2 / Si, silicon, germanium, mica, sapphire, ruby, indium phosphide, indium arsenide, gallium phosphide, gallium nitride, strontium titanate, zirconium oxide, silicon carbide, or quartz glass.

7. The application of the superionic conductor dielectric thin film according to claim 1 or 2 in the fabrication of electronic devices.

8. The application according to claim 7, characterized in that, The electronic device is a semiconductor device, an optoelectronic device, or a magneto-optical device.

9. A semiconductor device, characterized in that, Includes the superionic conductor dielectric thin film as described in claim 1 or 2; the semiconductor device is a field-effect transistor, an inverter circuit, a logic gate circuit, or a non-volatile magnetic memory device.

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