A method for fabricating a radio frequency switching device

Abstract

This application belongs to the field of semiconductor device technology and relates to a method for fabricating a radio frequency (RF) switch device, comprising: depositing a phase change material on a substrate to obtain a phase change material layer; fabricating a first electrode on the phase change material layer; depositing a conductive sacrificial layer at the junction of the first electrode and the phase change material layer; fabricating a second electrode on the phase change material layer and covering the conductive sacrificial layer with the second electrode; removing the electrode overlap cap at the junction of the first electrode and the second electrode to expose the conductive sacrificial layer; processing the conductive sacrificial layer to form a nano-gap between the first electrode and the second electrode, and forming a semi-suspended structure between the second electrode and the conductive sacrificial layer; using the first electrode as the input terminal of the RF switch device and the second electrode as the output terminal of the RF switch device to obtain the RF switch device. This application can fabricate RF switch devices and simultaneously significantly improve response speed and power tolerance.

Description

Technical Field

[0001] This application relates to the field of semiconductor device technology, and in particular to a method for fabricating a radio frequency switch device. Background Technology

[0002] High-performance switches are critical components in radio frequency (RF) circuits. With the widespread deployment of 5G technology, the gradual vision towards 6G, and the ongoing exploration in cutting-edge fields such as satellite communications and radar systems, the performance of RF switches is facing unprecedentedly stringent requirements. In these complex and sophisticated systems, RF switches, as the core components for signal path selection, switching, and routing, directly determine the sensitivity, linearity, power consumption, and reliability of the entire communication system. Research on high-performance RF switches is not only crucial for improving existing communication quality but also a key foundation for realizing future higher frequency bands, larger bandwidths, and more complex application scenarios.

[0003] Currently, high electron mobility transistors (HEMTs) based on second- and third-generation semiconductor materials (such as GaN and InP) are the core of high-speed, high-power electronic systems. GaN and InP devices possess a wider bandgap (GaN approximately 3.4 eV), a higher concentration of two-dimensional electron gas (2DEG), and faster electron mobility, enabling higher power density and superior high-frequency response characteristics. However, these devices still face several limitations when used as RF switches. First, although theoretically they have high mobility and fast saturation speed, bottlenecks such as output capacitance, parasitic inductance, charge traps, electron saturation speed, and critical electric field still exist during actual switching, preventing arbitrary increases in switching speed. For example, in GaN HEMTs, the phenomenon of "dynamic on-resistance deteriorating with high voltage switching" has been observed, affecting the high-frequency fast switching response capability. Second, although their power tolerance is higher than that of traditional silicon materials, their power handling capabilities (such as high voltage tolerance, high transient power surges, and thermal management) still present challenges in RF path switching scenarios. For example, in some radio frequency environments, switches must withstand extremely high transient power and high-frequency repetitive switching, and current GaNHEMT RF switch solutions do not fully meet these extreme conditions.

[0004] Furthermore, MEMS-based switches control ohmic or capacitive contacts through mechanical motion, offering advantages such as low power consumption and excellent transmission characteristics (low insertion loss, high isolation). Compared to gallium arsenide and silicon-based switches, MEMS switches possess numerous advantages in RF performance. However, they also have drawbacks in response speed and power handling. First, the switching time of a typical RF MEMS switch can be in the microsecond range (2µs ~ 40µs) or even longer, which is slower than semiconductor switches, potentially becoming a bottleneck in high-speed signal switching and rapid reconfiguration systems. Second, MEMS switches face challenges in reliability, such as dielectric layer charging, contact interface degradation, mechanical fatigue, and temperature drift, thus affecting power handling and lifespan. Therefore, despite the outstanding performance of MEMS switches in terms of low loss and high isolation, significant obstacles remain for their widespread application in RF systems requiring extremely high switching speeds and high power handling capabilities.

[0005] Therefore, in current mainstream RF switching technologies, there is still a lack of an ideal switching element that can simultaneously handle ultra-high-speed switching and high-power or high-frequency repetitive switching. In summary, existing RF switching solutions generally suffer from the following two main shortcomings:

[0006] 1. Insufficient response speed: Whether it is GaNHEMT type switch, MEMS switch or phase change switch, they all face speed bottlenecks in high frequency and high speed switching scenarios (such as MEMS at the microsecond level, GaN is difficult to improve infinitely under high speed parasitic limitations).

[0007] 2. Weak power tolerance: Especially in RF applications with transient power, power density and multiple rapid switching, existing switches cannot simultaneously meet the requirements of high power tolerance, thermal management, reliability and switching performance. Summary of the Invention

[0008] Therefore, it is necessary to provide a method for fabricating radio frequency switching devices to address the above-mentioned technical problems, which can fabricate radio frequency switching devices and simultaneously significantly improve response speed and power tolerance.

[0009] A method for fabricating a radio frequency switching device, comprising:

[0010] A phase change material layer is obtained by depositing a phase change material on a substrate;

[0011] A metal electrode is fabricated and patterned on a phase change material layer to obtain the first electrode;

[0012] A sacrificial structure is deposited and patterned at the junction of the first electrode and the phase change material layer to obtain a conductive sacrificial layer.

[0013] Another metal electrode is fabricated and patterned on the phase change material layer to obtain a second electrode, and the second electrode is covered with a conductive sacrificial layer.

[0014] Chemical mechanical polishing is used to remove the electrode overlap cap at the junction of the first and second electrodes, exposing the conductive sacrificial layer.

[0015] A wet etching method is used to process the conductive sacrificial layer, forming a nano-gap between the first electrode and the second electrode, and forming a semi-suspended structure between the second electrode and the conductive sacrificial layer. The first electrode is used as the input terminal of the RF switch device, and the second electrode is used as the output terminal of the RF switch device, thus obtaining the RF switch device.

[0016] In one embodiment, the second electrode and the conductive sacrificial layer form a semi-suspended structure, including:

[0017] An "L"-shaped void structure is formed between the first electrode, the second electrode, the phase change material layer, and the conductive sacrificial layer.

[0018] In one embodiment, the wet etching solution is an aluminum etching solution with a ratio of H3PO4:HNO3:H2O = 16:1:4.

[0019] In one embodiment, a metal electrode is fabricated and patterned on a phase change material layer to obtain a first electrode, comprising:

[0020] A metal electrode is obtained by depositing a film on a phase change material layer using magnetron sputtering, electron beam evaporation, or electroplating.

[0021] A metal electrode is patterned to obtain the first electrode.

[0022] In one embodiment, patterning a metal electrode to obtain a first electrode includes:

[0023] A photoresist mask is fabricated using ultraviolet lithography, and a metal electrode is patterned using dry etching or stripping methods to obtain the first electrode.

[0024] In one embodiment, a sacrificial structure is deposited and patterned at the junction of the first electrode and the phase change material layer to obtain a conductive sacrificial layer, comprising:

[0025] A sacrificial structure is obtained by depositing a film at the junction of the first electrode and the phase change material layer using magnetron sputtering or photolithography.

[0026] The sacrificial structure is patterned to obtain a conductive sacrificial layer.

[0027] In one embodiment, the sacrificial structure is patterned to obtain a conductive sacrificial layer, including:

[0028] The sacrificial structure is patterned using a stripping or photolithography method to obtain a conductive sacrificial layer.

[0029] In one embodiment, the substrate is made of sapphire, high-resistivity silicon, or glass.

[0030] In one embodiment, both the first electrode and the second electrode are made of pure metal material.

[0031] In one embodiment, the conductive sacrificial layer is made of a pure metallic material or a conductive compound material.

[0032] The above-mentioned method for fabricating radio frequency (RF) switching devices designs a wafer-level array RF switch comprising a substrate, a phase change material layer, a first electrode, a conductive sacrificial layer, and a second electrode. The first electrode and the second electrode serve as the input and output, respectively, which improves the switching response speed, power tolerance, isolation, and stability. It solves the technical problems of insufficient response speed and weak power tolerance of existing RF switches in high-frequency and high-speed switching scenarios, effectively improving the performance of RF switching devices. It is suitable for high-frequency and high-speed RF applications and has important application prospects in communication, radar systems, and other high-power electronic devices, especially in next-generation communication systems (particularly millimeter-wave, terahertz bands, and multi-channel fast reconfiguration scenarios). Attached Figure Description

[0033] Figure 1 This is a schematic flowchart of a method for fabricating a radio frequency switching device in one embodiment;

[0034] Figure 2 This is a schematic diagram of the architecture of a method for fabricating a radio frequency switching device in one embodiment;

[0035] Figure 3 This is a schematic diagram of an RF switch obtained by a method for fabricating an RF switch device in one embodiment.

[0036] Figure label:

[0037] Substrate 1, phase change material layer 2, first electrode 3, conductive sacrificial layer 4, second electrode 5. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0039] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this application, "multiple sets" means at least two sets, such as two sets, three sets, etc., unless otherwise explicitly specified.

[0040] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0041] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0042] This application provides a method for fabricating a radio frequency switching device, such as... Figures 1 to 3 As shown, in one embodiment, it includes:

[0043] Step 101: Deposit phase change material on the substrate to obtain a phase change material layer.

[0044] Specifically:

[0045] A phase change material thin film with a thickness of 50-500 nm is deposited on a substrate with a thickness of 100-2000 μm by magnetron sputtering or chemical vapor deposition to obtain a phase change material layer.

[0046] Step 102: A metal electrode is fabricated and patterned on the phase change material layer to obtain the first electrode.

[0047] Specifically:

[0048] A metal electrode is obtained by depositing a film on a phase change material layer using magnetron sputtering, electron beam evaporation, or electroplating.

[0049] A metal electrode is patterned to obtain the first electrode.

[0050] More specifically:

[0051] A metal electrode is obtained by depositing a thin film with a thickness of 100~5000 nm on a phase change material layer using magnetron sputtering, electron beam evaporation or electroplating.

[0052] A photoresist mask is fabricated using ultraviolet lithography as a protective layer, and a metal electrode is patterned using a dry etching method (such as inductively coupled plasma etching (ICP)) or a stripping method to obtain the first electrode.

[0053] Step 103: Deposit and pattern a sacrificial structure at the junction of the first electrode and the phase change material layer to obtain a conductive sacrificial layer.

[0054] Specifically:

[0055] A film (thin film) is deposited at the junction of the first electrode and the phase change material layer by magnetron sputtering or photolithography to obtain a sacrificial structure.

[0056] The sacrificial structure is patterned to obtain a conductive sacrificial layer.

[0057] More specifically:

[0058] A thin film with a thickness of 50~1000nm is deposited at the junction of the first electrode and the phase change material layer by magnetron sputtering or photolithography to obtain a sacrificial structure;

[0059] The sacrificial structure is patterned using lift-off or photolithography methods to obtain a conductive sacrificial layer.

[0060] Step 104: Prepare another metal electrode on the phase change material layer and pattern it to obtain a second electrode, and cover the second electrode with a conductive sacrificial layer.

[0061] Specifically:

[0062] A film (thin film) is deposited on a phase change material layer by magnetron sputtering, electron beam evaporation or electroplating to obtain another metal electrode, and the other metal electrode is covered with a conductive sacrificial layer;

[0063] The other metal electrode is patterned to obtain the second electrode.

[0064] More specifically:

[0065] A thin film with a thickness of 100~5000 nm is deposited on the phase change material layer by magnetron sputtering, electron beam evaporation or electroplating to obtain another metal electrode, and the other metal electrode is covered with a conductive sacrificial layer.

[0066] A photoresist mask is fabricated using ultraviolet lithography as a protective layer, and another metal electrode is patterned using a dry etching method (such as inductively coupled plasma etching (ICP)) or a stripping method to obtain a second electrode.

[0067] Step 105: Use chemical mechanical polishing to remove the electrode overlap cap at the junction of the first electrode and the second electrode, so that the conductive sacrificial layer is exposed.

[0068] Specifically:

[0069] Chemical mechanical polishing was performed using 50nm silicon oxide polishing slurry and polyurethane polishing pad to remove the electrode overlap cap at the junction of the first and second electrodes, thus exposing the conductive sacrificial layer.

[0070] In this step, the electrode overlap cap at the junction of the first electrode and the second electrode is the protrusion at the junction of the first electrode and the second electrode.

[0071] Step 106: The conductive sacrificial layer is processed by wet etching to form a nano gap between the first electrode and the second electrode, and to form a semi-suspended structure between the second electrode and the conductive sacrificial layer. The first electrode is used as the input terminal of the RF switch device, and the second electrode is used as the output terminal of the RF switch device to obtain the RF switch device.

[0072] Specifically:

[0073] A wet etching method is used to process the conductive sacrificial layer, forming a nano-gap between the first electrode and the second electrode, and forming a semi-suspended structure between the second electrode and the conductive sacrificial layer. This results in an "L"-shaped void structure between the first electrode, the second electrode, the phase change material layer, and the conductive sacrificial layer, with the void structure having a thickness (vertical dimension) of less than 500 nm and a depth (lateral dimension) satisfying [1 μm, 5 μm].

[0074] By using the first electrode as the input terminal of the radio frequency switch device and the second electrode as the output terminal of the radio frequency switch device, a radio frequency switch device is obtained.

[0075] In this step, it is necessary to strictly control parameters such as etching temperature and time in order to precisely control the lateral etching of the conductive sacrificial layer and accurately control the formation of nano-gaps. The specific control methods are existing technologies and will not be elaborated here.

[0076] The wet etching solution should be selective, that is, it should corrode the conductive sacrificial layer at a faster rate, while not reacting with the electrode material, phase change material, or substrate, or the reaction rate should be very slow; for example, an aluminum etching solution with a ratio of H3PO4 (85%): HNO3 (70%): H2O = (16:1:4) can be used.

[0077] In this embodiment, the substrate is made of materials such as sapphire, high-resistivity silicon, and glass. Preferably, a double-sided polished sapphire material with a thickness of 100~2000um is used.

[0078] The phase change material layer is made of materials such as vanadium oxide, germanium telluride, germanium-antimony alloy, bismuth vanadium oxide, and vanadium selenide. Preferably, vanadium oxide material with a thickness of 50~500nm is used.

[0079] Both the first and second electrodes are made of pure metal materials such as gold, tungsten, silver, copper, and nickel. Preferably, tungsten material with a wavelength of 100-5000 nm is used.

[0080] The conductive sacrificial layer is made of pure metal materials such as aluminum, titanium, and molybdenum, or conductive compound materials such as titanium nitride. Preferably, it is made of metallic aluminum with a thickness of 50~1000nm.

[0081] It should be noted that the choice of sacrificial layer material must ensure that the wet etching solution does not react with the substrate material and electrode material.

[0082] It should also be noted that magnetron sputtering, electron beam evaporation, electroplating, ultraviolet lithography, dry etching, atomic layer deposition, chemical vapor deposition, stripping, chemical mechanical polishing, and wet etching are all existing technologies and will not be elaborated here.

[0083] In this application, the radio frequency switch incorporates the conduction process of nanoplasma and material phase transition, and can automatically turn on according to the input signal power. Specifically:

[0084] 1. Nanoplasma conduction:

[0085] When a microwave signal exceeding the power threshold is input to the RF switch, metallic plasma is generated within the nanoslit, resulting in nanoslit metallic plasma conduction. The specific conduction process can be divided into three stages:

[0086] 1) Initial field emission: When a microwave signal exceeding the power threshold is input to the RF switch, i.e. a sufficiently high voltage is applied across the nanometer-scale electrode gap, electrons tunnel through the vacuum barrier, forming the initial field emission current.

[0087] 2) Ion generation: When the initial field emission current increases to a certain extent, a small amount of metal ions will be generated due to the thermal instability of the first or second electrode;

[0088] 3) Avalanche ionization: The presence of metal ions increases the gap pressure and reduces the mean free path of electrons, thereby causing electrons to collide with metal ions and cause avalanche ionization, forming a metal plasma discharge channel, which realizes nanoplasma conduction; nanoplasma conduction has an extremely fast (picosecond level) response speed, which is faster than traditional devices (which usually have nanosecond level switching time). At the same time, the metal plasma conductive channel generated when the two electrodes are connected makes the device have very low on-resistance and has a near-ideal turn-on state.

[0089] When a microwave signal not exceeding the power threshold is input to the RF switch, the RF switch does not conduct.

[0090] 2. Material phase change conduction:

[0091] After the microwave signal is input to the RF switch and the nanoplasma is turned on, the nanoplasma and the phase change material layer are essentially connected in parallel, generating leakage current. Due to the presence of leakage current and the combined effect of the nanoplasma thermal effect, the phase change material starts to heat up synchronously. Within nanoseconds, the temperature can reach the phase change threshold, and the phase change material forms a path from the insulating state to the metallic state. At this time, the induced current at the nanoplasma decreases until the arc is extinguished, realizing the signal energy transfer path switching from the nanoplasma to the phase change material, and the material completes the phase change (nanosecond level). When the phase change material is in the metallic state, it can withstand extremely high current density, enabling the device to continuously withstand high power, achieve a high voltage rise rate, excellent power withstand capability, and stable overcurrent capability.

[0092] The aforementioned method for fabricating RF switching devices designs a wafer-level array RF switch comprising a substrate, a phase change material layer, a first electrode, a conductive sacrificial layer, and a second electrode. The first and second electrodes serve as the input and output, respectively, improving switching response speed, power tolerance, isolation, and stability. This method solves the technical problems of insufficient response speed and weak power tolerance in existing RF switches during high-frequency and high-speed switching scenarios. It effectively improves the performance of RF switching devices, making them suitable for high-frequency and high-speed RF applications. They hold significant application potential in communication, radar systems, and other high-power electronic devices, particularly in next-generation communication systems (especially in millimeter-wave, terahertz bands, and multi-channel fast reconfiguration scenarios). Specifically:

[0093] 1. By forming a structure with nano-gaps through a phase change material layer and a conductive sacrificial layer, an extremely fast (picosecond-level) switching speed can be achieved, enabling rapid response.

[0094] 2. By generating a metal plasma response and phase change material layer during conduction, the device provides an extremely high voltage rise rate and excellent power tolerance. The device can withstand high power signal transmission, avoiding the failure problem of traditional RF switches under high power conditions.

[0095] 3. The semi-suspended structure formed by wet etching effectively controls and optimizes the resistance value of the device in the off state, improves the isolation and stability of the device, enables the switching device to have stable and reliable operation capability, avoids signal leakage in high-frequency operation, and solves the problem of poor isolation caused by the excessively small resistance value in the off state due to the close spacing of traditional phase change switches.

[0096] 4. By combining mature technologies such as magnetron sputtering and photolithography, it is possible to achieve large-scale, low-cost array production while ensuring an efficient and stable manufacturing process, which has strong market adaptability and industrialization advantages.

[0097] It should be understood that, although Figure 1 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order in which these steps are executed, and they can be performed in other orders. Furthermore, Figure 1 At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but may be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0098] In one specific embodiment, a 200-nanometer-thick VO2 film was grown on a sapphire substrate using magnetron sputtering to obtain a phase change material layer. A high-purity (99.99%) vanadium metal target was used during the sputtering process, and the process was carried out in a mixed atmosphere of argon (99.999%) and oxygen (99.999%). The distance between the target and the substrate was approximately 200 millimeters, the sputtering pressure was set to approximately 0.5 Pa, and the substrate temperature was maintained at 500°C. After deposition, the film was annealed at 525°C in a vacuum furnace under a pressure of approximately 2 Pa. A 1000 nm thick tungsten metal film is deposited as the first electrode, a 300 nm thick aluminum metal film is deposited as the conductive sacrificial layer, and a 1000 nm thick tungsten metal film is deposited as the second electrode. Wet etching can be performed using an aluminum etching solution with a ratio of H3PO4 (85%):HNO3 (70%):H2O = (16:1:4) at 50 degrees Celsius and an etching rate of approximately 200 nm / min.

[0099] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for fabricating a radio frequency switching device, characterized in that, include: A phase change material layer is obtained by depositing a phase change material on a substrate; A metal electrode is fabricated and patterned on a phase change material layer to obtain the first electrode; A sacrificial structure is deposited and patterned at the junction of the first electrode and the phase change material layer to obtain a conductive sacrificial layer. Another metal electrode is fabricated and patterned on the phase change material layer to obtain a second electrode, and the second electrode is covered with a conductive sacrificial layer. Chemical mechanical polishing is used to remove the electrode overlap cap at the junction of the first and second electrodes, exposing the conductive sacrificial layer. A wet etching method is used to process the conductive sacrificial layer, forming a nano-gap between the first electrode and the second electrode, and forming a semi-suspended structure between the second electrode and the conductive sacrificial layer. The first electrode is used as the input terminal of the radio frequency switch device, and the second electrode is used as the output terminal of the radio frequency switch device, thus obtaining the radio frequency switch device. The second electrode and the conductive sacrificial layer form a semi-suspended structure, including: An "L"-shaped void structure is formed between the first electrode, the second electrode, the phase change material layer, and the conductive sacrificial layer; When a microwave signal exceeding the power threshold is input to the radio frequency switch, metal plasma is generated within the nano-slit, resulting in nano-slit metal plasma conduction. After the microwave signal is input to the radio frequency switch and the nanoplasma is turned on, the phase change material changes from an insulating state to a metallic state to form a pathway, realizing the signal energy transfer path switching from the nanoplasma to the phase change material, and the material completes the phase change. When a microwave signal not exceeding the power threshold is input to the RF switch, the RF switch does not conduct.

2. The method for fabricating a radio frequency switching device according to claim 1, characterized in that, The wet etching solution is an aluminum etching solution with a ratio of H3PO4:HNO3:H2O = 16:1:

4.

3. A method for fabricating a radio frequency switching device according to claim 1 or 2, characterized in that, A metal electrode is fabricated and patterned on a phase change material layer to obtain a first electrode, comprising: A metal electrode is obtained by depositing a film on a phase change material layer using magnetron sputtering, electron beam evaporation, or electroplating. A metal electrode is patterned to obtain the first electrode.

4. The method for fabricating a radio frequency switching device according to claim 3, characterized in that, Patterning a metal electrode yields a first electrode, comprising: A photoresist mask is fabricated using ultraviolet lithography, and a metal electrode is patterned using dry etching or stripping methods to obtain the first electrode.

5. A method for fabricating a radio frequency switching device according to claim 1 or 2, characterized in that, A sacrificial structure is deposited and patterned at the junction of the first electrode and the phase change material layer to obtain a conductive sacrificial layer, comprising: A sacrificial structure is obtained by depositing a film at the junction of the first electrode and the phase change material layer using magnetron sputtering or photolithography. The sacrificial structure is patterned to obtain a conductive sacrificial layer.

6. The method for fabricating a radio frequency switching device according to claim 5, characterized in that, The sacrificial structure is patterned to obtain a conductive sacrificial layer, including: The sacrificial structure is patterned using a stripping or photolithography method to obtain a conductive sacrificial layer.

7. A method for fabricating a radio frequency switching device according to claim 1 or 2, characterized in that, The substrate is made of sapphire, high-resistivity silicon, or glass.

8. A method for fabricating a radio frequency switching device according to claim 1 or 2, characterized in that, Both the first and second electrodes are made of pure metal materials.

9. A method for fabricating a radio frequency switching device according to claim 1 or 2, characterized in that, The conductive sacrificial layer is made of pure metal or conductive compound materials.

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