Atomic-scale amorphous metal chalcogenide film and preparation and application thereof
By depositing metal cluster layers on the growth substrate and introducing chalcogenic element, a wafer-scale atomic amorphous metal chalcogen compound thin film is prepared, which solves the preparation problems in the prior art and achieves excellent switching ratio and ultra-thin thickness.
Patent Information
- Application Number
- CN202411985288.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-04
AI Technical Summary
The prior art is difficult to prepare atomic-scale amorphous metal chalcogenide films with excellent switching ratios and ultra-thin thicknesses, especially in terms of synthesis temperature and layered structure requirements.
By depositing metal cluster layers on the growth substrate and introducing chalcogenic element during vapor deposition, a wafer-level amorphous metal chalcogenic compound film was successfully prepared by controlling the reaction conditions using the high and low temperature zones in the tube container.
Complete uniformity and ultra-thin thickness (~1 nm) of atomic-level amorphous metal chalcogenide films are achieved, and excellent switching ratios and low ohmic contact resistance are shown in field effect transistors.
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Figure CN119753590A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of new material electronic devices, and in particular to an atomic-level amorphous metal sulfide compound film and the preparation and application thereof. Background Art
[0002] Two-dimensional atomic layer materials exhibit excellent physical and chemical properties and have broad application prospects in electronics, sensors, batteries, and catalysis. In particular, the amorphous structures of these materials exhibit electrical properties that are significantly different from those of crystalline materials due to the lack of long-range order and the high concentration of uncoordinated atoms on the surface. For example, graphene exhibits semi-metallic properties, while a single layer of amorphous carbon is an electrical insulator. The relative dielectric constant of amorphous boron nitride (BN) layers is significantly lower than that of its crystalline counterpart, which makes it highly promising for application in low-power logic devices. However, the bulk phase of amorphous materials usually does not have a layered structure and has large internal forces, making it difficult to obtain a few layers of materials through top-down methods such as mechanical exfoliation. In bottom-up chemical vapor deposition, unlike the two-dimensional growth mode favored by natural layered materials, amorphous materials tend to adopt an energetically more favorable island growth mode during growth due to their unpassivated dangling bond surfaces. Therefore, the preparation of amorphous films, especially atomically thick ones, remains a huge challenge. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide an atomic-level amorphous metal chalcogenide film with excellent on / off ratio and ultra-thin thickness.
[0004] Another technical problem to be solved by the present invention is to provide a method for preparing the atomic-level amorphous metal chalcogenide film.
[0005] The third technical problem to be solved by the present invention is to provide application of the atomic-level amorphous metal chalcogenide film.
[0006] To solve the above problems, the present invention provides an atomic-level amorphous metal chalcogenide film, characterized in that: the chemical formula of the film is MC x , 0<x≤1.5; wherein: M is any one of metal platinum (Pt), palladium (Pd), iridium (Ir), and rhodium (Rh); C is any one of sulfur (S), selenium (Se), and tellurium (Te) in the chalcogen elements.
[0007] The film is a wafer-sized, atomically uniform, amorphous structure with a thickness of ~1 nm and a diameter of 1 inch.
[0008] The method for preparing an atomic-level amorphous metal chalcogenide film as described above comprises the following steps: (1) On a growth substrate, a metal is deposited by physical vapor deposition technology or chemical photoreduction technology to form a metal cluster layer with a final thickness of 0.1-0.5 nm and a diameter of ~2 nm; the metal is any one of platinum, palladium, iridium, and rhodium; (2) Place the chalcogenide powder in a quartz boat, and place it in a tubular container in sequence along the direction of the gas flow together with the growth substrate on which the metal clusters are deposited, wherein the chalcogenide powder is placed in a high-temperature zone and the growth substrate is placed in a downstream low-temperature zone; first purge with a high-flux inert gas for 10 minutes, then introduce a mixed carrier gas, and then heat up at a heating rate of 5 °C / min to a center temperature of the tubular container of 150~500 °C, while its low-temperature zone is 120~170 °C; after 10 minutes of annealing, cool naturally with the furnace to obtain a wafer-level atomic-level amorphous metal chalcogenide compound film.
[0009] The growth substrate in step (1) refers to any one of amorphous silicon dioxide / silicon, single crystal molybdenum disulfide, single crystal hexagonal boron nitride, and single crystal graphene substrate, and its size is 1 inch.
[0010] In the step (1), the physical vapor deposition technology refers to evaporating metal atoms or clusters by electron beam evaporation process, and depositing metal clusters at a deposition rate of 0.01 Å / s by controlling the power and time of the electron beam; the chemical photoreduction technology refers to reducing metal ions in the solvent by ultraviolet light, and depositing metal clusters by controlling the power and time of the ultraviolet lamp.
[0011] The tubular container in step (2) refers to a tubular furnace with a heating device in the center.
[0012] In the step (2), the high flux inert gas refers to argon with a flow rate of 200 sccm; the mixed carrier gas refers to argon with a flow rate of 60 sccm and hydrogen with a flow rate of 10 sccm.
[0013] The central temperature of the tubular container in step (2) is 150-500°C, which means that when sulfur is used as a single substance, the central temperature is 150°C; when selenium is used as a single substance, the central temperature is 230°C; and when tellurium is used as a single substance, the central temperature is 500°C.
[0014] In the step (2), the low temperature zone of the tubular container is 120-170°C, which means that when sulfur is used as a single substance, the temperature of the low temperature zone is 120°C; when selenium is used as a single substance, the temperature of the low temperature zone is 120°C; when tellurium is used as a single substance, the temperature of the low temperature zone is 170°C.
[0015] The application of the atomic-level amorphous metal chalcogenide film as described above is characterized in that the atomic-level amorphous metal chalcogenide film is used as a buffer layer of a contact electrode in a field effect transistor in an electronic device.
[0016] Compared with the prior art, the present invention has the following advantages: 1. The present invention successfully prepares metal clusters with a diameter of 2nm on different substrates through electron beam evaporation process or chemical photoreduction method, greatly reduces the melting point of the metal and the reaction energy barrier between the metal and the chalcogenide elements, forms a new metal droplet-driven amorphous growth mechanism, and significantly reduces the synthesis temperature of the two-dimensional amorphous film to an ultra-low temperature growth temperature of 120~170℃, thereby synthesizing a completely uniform atomic-level amorphous film of wafer-level size.
[0017] 2. The atomic-level amorphous metal chalcogenide film of the present invention can achieve a complete film (ultra-thin thickness ~ 1 nm) at the wafer level (1 inch) by introducing extremely small metal clusters during the growth process, promoting the rapid growth and seamless splicing of nanobelts under non-equilibrium dynamics.
[0018] 3. The atomic-level amorphous metal chalcogenide film of the present invention is used as a buffer layer of the contact electrode to realize a field effect transistor with ultra-low ohmic contact resistance, and the switching characteristic of the device is as high as 3×10 7 .
[0019] 4. The present invention effectively reduces the contact resistance between the metal electrode and the channel material. Compared with the traditional chromium-gold metal as the contact electrode, it can provide a semi-metal buffer layer, effectively improve the charge injection efficiency, and show an excellent switching ratio in the field effect transistor. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.
[0021] Figure 1 The present invention is a schematic diagram of the preparation process of an atomic-level amorphous metal chalcogenide film.
[0022] Figure 2 This is a digital photo of the atomic-level amorphous metal chalcogenide film of the present invention.
[0023] Figure 3 The metallographic microscope image (left) and atomic force microscope image (right) of the atomic-level amorphous metal chalcogenide film of the present invention, as well as the thickness curve graph (the inset graph in the right graph).
[0024] Figure 4The spherical aberration-corrected high-angle annular dark-field scanning transmission electron microscope image (left) and element distribution map (right) of the atomic-level amorphous metal chalcogenide film of the present invention.
[0025] Figure 5 This is a transmission electron microscope image of the atomic-level amorphous metal chalcogenide (platinum-based, iridium-based, palladium-based, rhodium-based) film of the present invention, with the spherical aberration of the condenser corrected.
[0026] Figure 6 This is a selected electron diffraction pattern of the atomic-level amorphous metal chalcogenide film of the present invention.
[0027] Figure 7 The atomic-level amorphous metal chalcogenide PtSe of the present invention x Voltage-current curves of the films at different annealing temperatures.
[0028] Figure 8 The atomic-level amorphous metal chalcogenide PtSe of the present invention x The conductivity change of the film at different annealing temperatures.
[0029] Fig. 9 The atomic-level amorphous metal chalcogenide PtSe of the present invention x Transfer characteristic curves of the film at different annealing temperatures.
[0030] Fig.10 The atomic-level amorphous PtSe x A structural comparison diagram of a field effect transistor with a buffer layer as a contact electrode and a field effect transistor with a traditional chromium-gold as a contact electrode.
[0031] Fig.11 The atomic-level amorphous PtSe x Voltage-current curve of a field effect transistor with a buffer layer as a contact electrode and a field effect transistor with a traditional chromium-gold as a contact electrode.
[0032] Fig.12 The atomic-level amorphous PtSe x Transfer characteristic curves of a field effect transistor with a buffer layer as a contact electrode and a field effect transistor with a traditional chromium-gold as a contact electrode. DETAILED DESCRIPTION
[0033] An atomically amorphous metal chalcogenide film, the chemical formula of which is MC x, 0<x≤1.5; where: M is any one of the metals platinum (Pt), palladium (Pd), iridium (Ir), rhodium (Rh); C is any one of the chalcogen elements sulfur (S), selenium (Se), tellurium (Te). The film is a wafer-sized atomic-level completely uniform amorphous structure with a thickness of ~1nm and a diameter of 1 inch.
[0034] Its preparation method is as follows Figure 1 As shown, the following steps are included: ⑴ On the growth substrate, the metal is deposited by physical vapor deposition technology or chemical photoreduction technology to form a metal cluster layer with a final thickness of 0.1~0.5 nm and a diameter of ~2 nm; the metal refers to any one of platinum, palladium, iridium, and rhodium.
[0035] Wherein: the growth substrate refers to any one of amorphous silicon dioxide / silicon, single crystal molybdenum disulfide, single crystal hexagonal boron nitride, and single crystal graphene substrate, and its size is 1 inch.
[0036] Physical vapor deposition technology refers to the use of electron beam evaporation process to evaporate metal atoms or clusters, and by controlling the electron beam power and time, metal clusters are deposited at a deposition rate of 0.01 Å / s; chemical photoreduction technology refers to the use of ultraviolet light to reduce metal ions in the solvent, and metal clusters are deposited by controlling the power and time of the ultraviolet lamp.
[0037] ⑵ Place the chalcogenide powder in a quartz boat, and place it in a tubular container in sequence along the direction of the airflow together with the growth substrate of the deposited metal clusters, wherein the chalcogenide powder is placed in the high temperature zone and the growth substrate is placed in the downstream low temperature zone; the tubular container refers to a tubular furnace with a heating device in the center.
[0038] First, purge with argon gas at a flow rate of 200 sccm for 10 minutes, then introduce a mixed carrier gas consisting of argon gas at a flow rate of 60 sccm and hydrogen gas at a flow rate of 10 sccm, and then heat up at a heating rate of 5 ℃ / min to a central temperature of the tubular container of 150~500 ℃, and its low temperature zone is 120~170 ℃. After 10 minutes of annealing and natural cooling in the furnace, a wafer-sized atomic-level amorphous metal chalcogenide film is obtained.
[0039] Among them: the central temperature of the tubular container is 150~500 ℃, which means that when sulfur is used, the central temperature is 150 ℃; when selenium is used, the central temperature is 230 ℃; when tellurium is used, the central temperature is 500 ℃. The low temperature zone of the tubular container is 120~170 ℃, which means that when sulfur is used, the low temperature zone temperature is 120 ℃; when selenium is used, the low temperature zone temperature is 120 ℃; when tellurium is used, the low temperature zone temperature is 170 ℃. That is, when synthesizing sulfide, the central temperature is 150 ℃ and the low temperature zone temperature is 120 ℃; when synthesizing selenide, the central temperature is 230 ℃ and the low temperature zone temperature is 120 ℃; when synthesizing telluride, the central temperature is 500 ℃ and the low temperature zone temperature is 170 ℃.
[0040] The use of metal clusters with a diameter of ~2 nm as metal precursors in the present invention is a key condition for synthesizing completely uniform amorphous states at the atomic scale. The ultra-low temperature growth (120~170 ℃) is to melt the metal, and after it becomes liquid metal, it promotes the growth of amorphous nanobelts, thereby preventing the amorphous film from agglomerating or crystallizing due to heat, thereby ensuring the integrity and atomic-level thickness of the film.
[0041] Application of an atomic-level amorphous metal sulfide compound film: The atomic-level amorphous metal sulfide compound film is used as a buffer layer of a contact electrode in a field effect transistor in an electronic device.
[0042] Example 1 Figure 1 As shown in the figure, an atomic-scale amorphous metal chalcogenide film is first prepared, and then the PtSe x Field effect transistor as a buffer layer for contact electrodes: Through micro-nano processing and physical vapor deposition technology, a local heterojunction of molybdenum disulfide and amorphous platinum selenide is constructed on a single-layer molybdenum disulfide substrate, and then a metal electrode is constructed on the amorphous platinum selenide. The specific process is as follows: ⑴ Using electron beam exposure technology, a layer of polymethyl methacrylate was spin-coated on the surface of the MoS2 single crystal and a 5×5 um 2 electrode channel.
[0043] (2) Deposit metal clusters with a thickness of 0.1 nm and a diameter of ~2 nm on the single crystal substrate obtained in step 1 by physical vapor deposition at a rate of 0.01 Å / s, or by chemical photoreduction at a power of 1400 µW / cm 2 The metal clusters were reduced by 365 nm UV light for one hour, and then the PMMA on the surface of MoS2 single crystal was cleaned with acetone detergent.
[0044] ⑶ Place the chalcogenide powder source in a quartz boat, and place it in a tubular furnace along the direction of the gas flow in sequence with the growth substrate of the deposited metal clusters, where the selenium element is placed in the high-temperature zone and the growth substrate is placed in the downstream low-temperature zone. First, purge with a high-throughput 200 sccm argon gas for 10 minutes, then introduce a mixed carrier gas with a flow rate of 60 sccm argon and 10 sccm hydrogen, and then heat up at a heating rate of 5 ℃ / min until the center temperature of the tubular container is 230 ℃ and the temperature in the low-temperature zone is 120 ℃. After 10 minutes of annealing, cool naturally with the furnace, and then use electron beam exposure and electron beam evaporation processes, and then in the electrode channel in step 1 and 50×50 um 2 5 nm Cr and 50 nm Au were evaporated on the electrode channel and cleaned with acetone to construct atomic-level amorphous platinum selenide PtSe x (x≈1.42) as the contact buffer layer of an n-type field effect transistor.
[0045] Comparative Example 1 Preparation of a field effect transistor with chromium-gold as the contact electrode: First, a layer of polymethyl methacrylate was spin-coated on the surface of an atomic-level molybdenum disulfide substrate and a 5×5 um 2 and 50×50 um 2 The electrode channel is then formed by electron beam evaporation of metal to deposit 5 nm Cr and 50 nm Au. After cleaning with acetone, a traditional n-type field effect transistor with chromium-gold as the contact electrode is constructed.
[0046] The basic structure of the wafer-scale atomically amorphous metal chalcogenide film obtained in Example 1 and the atomically amorphous PtSe x The performance of the field effect transistor with the thin film as the buffer layer of the contact electrode and the field effect transistor with the chromium-gold of comparative example 1 as the contact electrode were tested:
Infrastructure Characterization
[0047] Spherical aberration corrected high-angle annular dark-field scanning transmission electron microscope test, such as Figure 4 As shown, the atomic-level amorphous metal chalcogenide film has a uniform and continuous atomic-level structure.
[0048] Tested by transmission electron microscope with spherical aberration correction of condenser, such as Figure 5As shown, the metal atoms in the atomically amorphous metal chalcogenide film (platinum-based, iridium-based, palladium-based, and rhodium-based) are randomly distributed in the film, indicating that the atomically amorphous metal chalcogenide film has the characteristics of long-range disorder and amorphous.
[0049] After electron diffraction test, such as Figure 6 As shown, the electron diffraction feature of the atomic-level amorphous metal chalcogenide film is a broad halo, indicating that the metal chalcogenide film has an amorphous structure.
[0050]
Conductive properties test at different temperatures
[0051]
Performance test of field effect transistor
Claims
1. An atomic-level amorphous metal chalcogenide film, characterized in that: The chemical formula of the film is MC x , 0<x≤1.5; wherein: M is any one of metal platinum, palladium, iridium, and rhodium; C is any one of sulfur, selenium, and tellurium in the chalcogen elements.
2. The atomic-level amorphous metal chalcogenide thin film according to claim 1, characterized in that: The film is a wafer-sized, atomically uniform, amorphous structure with a thickness of ~1 nm and a diameter of 1 inch.
3. The method for preparing an atomic-level amorphous metal chalcogenide film according to claim 1 or 2, comprising the following steps: (1) On a growth substrate, a metal is deposited by physical vapor deposition technology or chemical photoreduction technology to form a metal cluster layer with a final thickness of 0.1-0.5 nm and a diameter of ~2 nm; the metal is any one of platinum, palladium, iridium, and rhodium; (2) Place the chalcogenide powder in a quartz boat, and place it in a tubular container in sequence along the direction of the gas flow together with the growth substrate on which the metal clusters are deposited, wherein the chalcogenide powder is placed in a high-temperature zone and the growth substrate is placed in a downstream low-temperature zone; first purge with a high-flux inert gas for 10 minutes, then introduce a mixed carrier gas, and then heat up at a heating rate of 5 °C / min to a center temperature of the tubular container of 150~500 °C, while its low-temperature zone is 120~170 °C; after 10 minutes of annealing, cool naturally with the furnace to obtain a wafer-level atomic-level amorphous metal chalcogenide compound film.
4. The method for preparing an atomic-level amorphous metal chalcogenide thin film according to claim 3, characterized in that: The growth substrate in step (1) refers to any one of amorphous silicon dioxide / silicon, single crystal molybdenum disulfide, single crystal hexagonal boron nitride, and single crystal graphene substrate, and its size is 1 inch.
5. The method for preparing an atomic-level amorphous metal chalcogenide thin film according to claim 3, characterized in that: In the step (1), the physical vapor deposition technology refers to evaporating metal atoms or clusters by electron beam evaporation process, and depositing metal clusters at a deposition rate of 0.01 Å / s by controlling the power and time of the electron beam; the chemical photoreduction technology refers to reducing metal ions in the solvent by ultraviolet light, and depositing metal clusters by controlling the power and time of the ultraviolet lamp.
6. The method for preparing an atomic-level amorphous metal chalcogenide thin film according to claim 3, characterized in that: The tubular container in step (2) refers to a tubular furnace with a heating device in the center.
7. The method for preparing an atomic-level amorphous metal chalcogenide thin film according to claim 3, characterized in that: In the step (2), the high flux inert gas refers to argon with a flow rate of 200 sccm; the mixed carrier gas refers to argon with a flow rate of 60 sccm and hydrogen with a flow rate of 10 sccm.
8. The method for preparing an atomic-level amorphous metal chalcogenide thin film according to claim 3, characterized in that: The central temperature of the tubular container in step (2) is 150-500°C, which means that when sulfur is used as a single substance, the central temperature is 150°C; when selenium is used as a single substance, the central temperature is 230°C; and when tellurium is used as a single substance, the central temperature is 500°C.
9. The method for preparing an atomic-level amorphous metal chalcogenide thin film according to claim 3, characterized in that: In the step (2), the low temperature zone of the tubular container is 120-170°C, which means that when sulfur is used as a single substance, the temperature of the low temperature zone is 120°C; when selenium is used as a single substance, the temperature of the low temperature zone is 120°C; when tellurium is used as a single substance, the temperature of the low temperature zone is 170°C.
10. The use of an atomic-level amorphous metal chalcogenide film as claimed in claim 1 or 2, characterized in that: The atomic-level amorphous metal sulfide compound film is used as a buffer layer of a contact electrode in a field effect transistor in an electronic device.