Laser-driven phase change radio frequency switch and preparation method thereof

Abstract

The invention discloses a laser-driven phase change radio frequency switch, which comprises a metal reflecting layer and a phase change layer, and is characterized in that laser heats the phase change layer through reflected light of the metal reflecting layer to change the state of the phase change layer; the first radio frequency transmission layer and the second radio frequency transmission layer are connected when the phase change layer is changed from a high-resistance state to a low-resistance state, and the first radio frequency transmission layer and the second radio frequency transmission layer are disconnected when the phase change layer is changed from the low-resistance state to the high-resistance state. Wherein the first electrode in the first radio frequency transmission layer is the input end of the phase change radio frequency switch, and the second electrode in the second radio frequency transmission layer is the output end of the phase change radio frequency switch. According to the phase change radio frequency switch disclosed by the invention, the phase change material is directly heated through laser, stray capacitance caused by a micro heater is eliminated, and insertion loss is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave radio frequency devices, and in particular relates to a laser-driven phase-change radio frequency switch and a preparation method thereof. Background Art

[0002] Current mainstream RF switches are reaching their physical limits. SOI CMOS-based devices are constrained by large parasitic capacitance, significantly degrading performance, such as insertion loss, at high frequencies. MEMS technology, while theoretically capable of ultra-low insertion loss, is limited by mechanical hysteresis and packaging reliability issues. These issues force existing solutions to compromise signal quality and energy consumption when supporting millimeter-wave frequencies, making it difficult to meet the synergistic demands of ultra-high speeds and ultra-low power consumption for future smart devices. Faced with this technological bottleneck, RF switches based on phase-change materials (PCMs) have emerged as a breakthrough option. PCMs achieve solid-state control of the RF path through a reversible phase transition between an amorphous (high resistance) and crystalline (low resistance) state via electrical stimulation. Core materials, such as chalcogenides (GeTe), can achieve resistance variations of up to four to five orders of magnitude, switching speeds down to sub-microseconds, and their non-volatility reduces static power consumption to near zero. Furthermore, PCM RF switches offer the advantages of low loss, high linearity, and scalability.

[0003] However, in frequency bands above 67GHz, the insertion loss of phase-change RF switches still cannot meet application requirements. Due to the parasitic capacitance caused by the microheater in the indirect heating structure, the insertion loss of the phase-change RF switch deteriorates with increasing frequency. In a certain high-frequency band, the insertion loss surges, making it intolerable for the RF front-end system. In addition, the heat conduction of the microheater in the indirect heating structure has great losses. In order to achieve electrical isolation, an isolation layer is introduced. The existence of the isolation layer leads to low thermal utilization and affects the rapid heat dissipation process during the amorphization process, which brings about problems such as increased power consumption and slower phase change speed. Therefore, without solving the driving problem of the phase-change RF switch state switching, it is difficult to further optimize the device's performance such as insertion loss and power consumption.

[0004] Existing solutions rely on applying an external laser to the phase-change RF switch, resulting in low device integration and difficult packaging. Other solutions utilize a laser-driven optical waveguide structure fabricated on top of the device. However, this approach presents several manufacturing challenges. Optical waveguides made of single-crystal silicon or other dielectrics are difficult to fabricate effectively on-chip, and excessively high fabrication temperatures can cause volatilization or damage of the phase-change material. Furthermore, coupling structures that rely solely on the waveguide's own inclined surface can cause unevenness, leading to partial laser penetration and poor coupling efficiency. Summary of the Invention

[0005] In response to the defects of the existing technology and the need for improvement, its purpose is to solve the parasitic capacitance and heat dissipation problems generated by the microheater when the traditional microheater drives the phase change RF switch, and secondly to solve the problem of low coupling efficiency caused by relying solely on the inclined structure of the optical waveguide itself when laser heating in the existing technology.

[0006] The present invention provides a laser-driven phase-change radio frequency switch, comprising:

[0007] a substrate, located on a semiconductor substrate;

[0008] a substrate isolation layer, disposed on the substrate;

[0009] an optical waveguide lower cladding layer, arranged on the substrate isolation layer;

[0010] a laser reflection structure disposed on the optical waveguide lower cladding, wherein the laser reflection structure comprises an optical waveguide core layer inclined surface structure support layer, an optical waveguide core layer, and a metal reflection layer, wherein the metal reflection layer is disposed between the optical waveguide core layer inclined surface structure support layer and the optical waveguide core layer, wherein the metal reflection layer has an inclined surface structure and is bonded to the inclined surface ends of the optical waveguide core layer inclined surface structure support layer and the inclined surface ends of the optical waveguide core layer;

[0011] An optical waveguide upper cladding, wherein the laser reflection structure is embedded in the optical waveguide upper cladding and then disposed on the optical waveguide lower cladding, and the top of the optical waveguide upper cladding includes a window structure;

[0012] A phase change layer is provided in the window structure of the upper cladding of the optical waveguide, and the laser heats the phase change layer by the reflected light of the metal reflective layer, thereby changing the material state of the phase change layer from a high resistance state to a low resistance state or from a low resistance state to a high resistance state;

[0013] The first RF transmission layer and the second RF transmission layer are arranged on the upper cladding of the optical waveguide. The first RF transmission layer and the second RF transmission layer are on the same horizontal plane and are respectively arranged at both ends of the phase change layer without contact. When the phase change layer changes from a high resistance state to a low resistance state, the first RF transmission layer is connected to the second RF transmission layer. When the phase change layer changes from a low resistance state to a high resistance state, the first RF transmission layer and the second RF transmission layer are disconnected. The first electrode in the first RF transmission layer is the input end of the phase change RF switch, and the second electrode in the second RF transmission layer is the output end of the phase change RF switch.

[0014] The present invention also provides a method for preparing the above-mentioned laser-driven phase-change radio frequency switch, comprising:

[0015] S1: Depositing a substrate isolation layer on a substrate by plasma enhanced chemical vapor deposition, wherein the substrate comprises one or more of silicon, diamond, sapphire, silicon carbide, indium phosphide, gallium arsenide, gallium nitride, quartz, and glass; and the substrate isolation layer comprises one or more of silicon dioxide, silicon nitride, aluminum nitride, and aluminum oxide;

[0016] S2: depositing an optical waveguide lower cladding layer on the substrate isolation layer by plasma enhanced chemical vapor deposition, wherein the optical waveguide lower cladding layer includes one of silicon dioxide, silicon nitride, and SU-8;

[0017] S3: depositing an optical waveguide core layer inclined surface structure support layer on the optical waveguide lower cladding layer by plasma enhanced chemical vapor deposition, patterning the support layer by photolithography, and etching the optical waveguide core layer inclined surface structure support layer with an inclined angle by sidewall inclined etching process, wherein the angle between the inclined surface end of the optical waveguide core layer inclined surface structure support layer and the optical waveguide lower cladding layer is 30° to 60°, and the material of the optical waveguide core layer inclined surface structure support layer includes one or more of single crystal silicon, silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, and SU-8;

[0018] S4: using photolithography to produce an inclined surface pattern on the inclined surface end of the optical waveguide core layer inclined surface structure support layer in step S3, and sequentially depositing metal materials by magnetron sputtering or electron beam evaporation to obtain a metal reflective layer, wherein the metal reflective layer is bonded to the inclined surface end of the optical waveguide core layer inclined surface structure support layer, and the angle between the metal reflective layer and the optical waveguide lower cladding layer is the same as the angle between the inclined surface end of the optical waveguide core layer inclined surface structure support layer and the optical waveguide lower cladding layer, and the material of the metal reflective layer is a metal material with a reflective function;

[0019] S5: depositing an optical waveguide core layer material on the metal reflective layer in step S4 by plasma-enhanced chemical vapor deposition, and planarizing the upper surface by chemical mechanical polishing, obtaining a mask pattern of the optical waveguide core layer by photolithography, and obtaining the optical waveguide core layer by an etching process, wherein the bevel end of the optical waveguide core layer is bonded to the metal reflective layer, and the material of the optical waveguide core layer includes one or more of single crystal silicon, silicon nitride, and aluminum oxide;

[0020] S6: depositing an optical waveguide upper cladding on the laser reflection structure composed of the optical waveguide core layer, the metal reflection layer, and the optical waveguide core layer inclined surface structure support layer, and the optical waveguide lower cladding, depositing the optical waveguide upper cladding material on the laser reflection structure by plasma enhanced chemical vapor deposition, obtaining a phase change layer pattern by photolithography, obtaining a window structure by etching, and obtaining the optical waveguide upper cladding, wherein the material of the optical waveguide upper cladding comprises one of silicon dioxide, silicon nitride, and SU-8;

[0021] S7: depositing a phase change layer on the cladding of the optical waveguide, depositing a phase change material on the cladding of the optical waveguide by magnetron sputtering, patterning the phase change material by photolithography, performing mask protection on the phase change material in the window area, etching away the phase change material outside the pattern area by etching, and obtaining the phase change layer after debonding, wherein the phase change layer comprises a chalcogenide compound or a chalcogenide compound doped with one or more elements selected from the group consisting of indium, hafnium, yttrium, scandium, gallium, and titanium, wherein the chalcogenide compound is germanium telluride, antimony telluride, or germanium antimony telluride;

[0022] S8: depositing a radio frequency transmission layer material on the phase change layer, patterning a first electrode and a second electrode on the deposited radio frequency transmission layer material by a photolithography method, sequentially depositing metal materials by an electron beam evaporation coating method, and removing the photoresist and the metal material outside the patterned area by a wet stripping process, wherein the wet stripping process specifically comprises sequentially cleaning with acetone, a stripping solution, isopropyl alcohol, and ultrapure water to obtain a radio frequency transmission layer, wherein the radio frequency transmission layer includes a first electrode, a second electrode, and a ground electrode, and the material of the radio frequency transmission layer is a metal material;

[0023] S9: A passivation layer material is deposited on the radio frequency transmission layer using plasma enhanced chemical vapor deposition, the passivation layer material is patterned using photolithography, and the first electrode and the second electrode in the radio frequency transmission layer are exposed, the passivation layer material outside the pattern area is etched away by etching, and the passivation layer is obtained after degumming, wherein the passivation layer material includes one or more of silicon dioxide, silicon nitride, silicon oxynitride, aluminum oxide, and aluminum nitride.

[0024] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0025] The traditional indirect heating structure of the microheater heating method is changed. The optical waveguide structure is used to transmit laser on the chip to directly heat the phase change material, eliminating the parasitic capacitance caused by the microheater, reducing the insertion loss, and extending the working frequency band to terahertz. Compared with the indirect heating method using a microheater, the energy loss during laser transmission in the laser drive structure is lower, which effectively improves the energy utilization rate and reduces the operating power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic front cross-sectional view of a laser-driven phase-change radio frequency switch provided in an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of a right-side cross-sectional structure of a laser-driven phase-change radio frequency switch provided in an embodiment of the present invention;

[0028] Figure 3A top view of a laser reflection structure of a laser-driven phase-change radio frequency switch provided by an embodiment of the present invention;

[0029] Figure 4 A top view of a phase change layer, a radio frequency transmission layer, and a passivation layer of a laser-driven phase change radio frequency switch provided in an embodiment of the present invention;

[0030] In the figure, 1 is a substrate, 2 is a substrate isolation layer, 3 is an optical waveguide lower cladding layer, 4 is an optical waveguide core layer inclined surface structure support layer, 5 is an optical waveguide core layer, 6 is a metal reflective layer, 7 is an optical waveguide upper cladding layer, 8 is a phase change layer, and 9 is a radio frequency transmission layer, wherein 91 is a first radio frequency transmission layer, 92 is a second radio frequency transmission layer, 93 and 94 are ground electrodes, and 10 is a passivation layer;

[0031] Figure 5 The relative position relationship between the metal reflective layer and the phase change layer of a laser-driven phase change radio frequency switch provided in an embodiment of the present invention;

[0032] Figure 6 A flow chart for preparing a laser-driven phase-change radio frequency switch provided in an embodiment of the present invention;

[0033] Figure 7 This is an on-state S-parameter simulation curve of a phase-change RF switch with a traditional heating structure provided by an embodiment of the present invention;

[0034] Figure 8 This is a simulation curve of the on-state S parameters of a laser-driven phase-change RF switch provided by an embodiment of the present invention;

[0035] Figure 9 COMSOL thermal simulation curve of the Set process of a laser-driven phase-change RF switch provided in an embodiment of the present invention;

[0036] Figure 10 This is a COMSOL thermal simulation curve of the reset process of a laser-driven phase-change RF switch provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0038] In the present invention, the terms "first", "second", etc. (if any) in the present invention and the drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0039] Example 1

[0040] The present invention discloses a laser-driven phase-change radio frequency switch. Figure 1 A schematic diagram of the front cross-sectional structure of a laser-driven phase-change radio frequency switch provided in an embodiment of the present invention; Figure 2 A schematic diagram of the side structure of a laser-driven phase-change radio frequency switch provided by an embodiment of the present invention. Figure 1 As shown, the laser-driven phase-change RF switch includes: a substrate 1, a substrate isolation layer 2, an optical waveguide lower cladding layer 3, an optical waveguide core layer inclined surface structure support layer 4, an optical waveguide core layer 5, a metal reflective layer 6, an optical waveguide upper cladding layer 7, a phase change layer 8, an RF transmission layer 9, and a passivation layer 10. The substrate isolation layer 2 is located on the substrate 1, the optical waveguide lower cladding layer 3 is located on the substrate isolation layer 2, and the optical waveguide core layer inclined surface structure support layer 4, the optical waveguide core layer 5, and the metal reflective layer 6 are combined to form a laser reflective structure located on the optical waveguide lower cladding layer 3, wherein the metal reflective layer 6 is disposed between the optical waveguide core layer inclined surface structure support layer 4 and the optical waveguide core layer 5.

[0041] like Figure 1 As shown, in the laser reflective structure, one end of the optical waveguide core layer inclined surface structure support layer 4 is inclined, and the metal reflective layer 6 has an inclined surface structure and is disposed on the optical waveguide core layer inclined surface structure support layer 4. One surface of the metal reflective layer 6 is connected to the optical waveguide core layer inclined surface structure support layer 4, and the other surface is connected to the optical waveguide core layer 5. The angle between the metal reflective layer 6 and the optical waveguide lower cladding layer 3 ranges from 30° to 60°. Preferably, when the angle is 45°, the metal reflective layer 6 has the highest efficiency in reflecting horizontal laser light.

[0042] like Figure 2 As shown, a laser reflective structure composed of an optical waveguide core layer slope structure support layer 4, an optical waveguide core layer 5, and a metal reflective layer 6 is embedded in an optical waveguide upper cladding layer 7. The optical waveguide upper cladding layer 7 is disposed above the optical waveguide lower cladding layer 3, and the top of the optical waveguide upper cladding layer 7 has a window structure filled with a phase change layer 8. The phase change layer 8 is located directly above the metal reflective layer 6, and the thickness of the phase change layer 8 is less than the distance from the top of the optical waveguide upper cladding layer to the top of the laser reflective structure.

[0043] In one embodiment, the laser is reflected by the metal reflective layer 6 and used to heat the phase change layer 8 and change the state of the phase change layer 8, such as from an amorphous state to a crystalline state or from a crystalline state to an amorphous state. The amorphous state corresponds to a high-resistance state of the phase change layer 8, and the crystalline state corresponds to a low-resistance state of the phase change layer 8.

[0044] In an optional embodiment of the present invention, the window depth of the window structure on the optical waveguide upper cladding 7 is less than the thickness of the optical waveguide upper cladding 7, and the phase change layer 8 is located in the window of the optical waveguide upper cladding 7. The thickness of the phase change layer 8 is equal to the window depth and is embedded in the window area of ​​the optical waveguide upper cladding 7. Specifically, the radio frequency transmission layer 9 is provided on the optical waveguide upper cladding 7, and the radio frequency transmission layer 9 includes a radio frequency transmission layer 91, a radio frequency transmission layer 92 and ground electrodes 93 and 94, as shown in FIG. Figure 1 Combine Figure 3 and Figure 4 As shown, the RF transmission layer 91, the RF transmission layer 92 and the ground electrodes 93 and 94 are on the same horizontal plane. The RF transmission layer 91 and the RF transmission layer 92 are respectively arranged at the two ends of the phase change layer 8, and the two do not touch each other. The first electrode and the second electrode are respectively arranged on the RF transmission layer 91 and the RF transmission layer 92, wherein the first electrode is connected to the input end of the RF signal and the second electrode is the output end of the RF signal. When the phase change layer 8 is in a high-resistance state, the first electrode and the second electrode are disconnected. When the phase change layer 8 is in a low-resistance state, the first electrode and the second electrode are connected through the phase change layer 8. The RF transmission layer 91 and the RF transmission layer 92 form an RF transmission channel with the phase change layer 8 in the window structure, forming the switching functional area of ​​the phase change RF switch. The passivation layer 10 is located above the RF transmission layer 91 and the RF transmission layer 92, and is filled directly above the phase change material filling the window structure to protect the device structure and the phase change material. The area of ​​the passivation layer 10 is greater than or equal to the area of ​​the phase change layer not covered by the RF transmission layer, that is, the area of ​​the phase change material in the window structure, wherein the first electrode is the input end of the phase change RF switch, and the second electrode is the output end of the phase change RF switch.

[0045] Figure 3 A top view of a laser reflection structure of a laser-driven phase-change radio frequency switch provided by an embodiment of the present invention; as shown in the figure, the dotted line portion is the lateral width of the metal reflection layer when viewed from above. Figure 4 A top view of a phase change layer, a radio frequency transmission layer, and a passivation layer of a laser-driven phase change radio frequency switch provided in an embodiment of the present invention; the size of the passivation layer 10 is adjustable, refer to Figure 4 As shown, the red dotted line indicates an adjustable range of the passivation layer 10. It should be understood by those skilled in the art that the shape of the passivation layer 10 is not limited to Figure 4 As shown, any other shape that can cover the phase change layer area not covered by the RF transmission layers 91 and 92. The areas on the RF transmission layer 91 and the RF transmission layer 92 not covered by the passivation layer 10 are the first electrode and the second electrode respectively.

[0046] Further, in order to more clearly describe the relationship between the metal reflective layer 6 and the phase change layer 8, refer to Figure 5As shown, x1 is the length of the phase change layer 8 in the x-direction, x2 is the length of the metal reflective layer 6 in the x-direction, Δx is the offset length of the leftmost end of the metal reflective layer 6 in the x-direction relative to the leftmost end of the phase change layer 8 in the x-direction, y0 is the length of the bottom end of the phase change layer 6 in the y-direction relative to the bottom end of the optical waveguide core layer 5, and θ is the tilt angle of the metal reflective layer. The relative positional relationship between the phase change layer 8 and the metal reflective layer 6 satisfies: Δx = y0 × tan(π / 2 - 2θ). In the direction perpendicular to the xy coordinate axis, the length of the metal reflective layer 6 is greater than or equal to the length of the phase change layer.

[0047] In an optional embodiment, the length x2 of the metal reflective layer 6 in the x direction is greater than or equal to the length x1 of the phase change layer in the x direction; the optimal range of the angle θ between the metal reflective layer 6 and the optical waveguide lower cladding 3 is 30° to 60°. The substrate 1 includes but is not limited to one or more of silicon, diamond, sapphire, silicon carbide, indium phosphide, gallium arsenide, gallium nitride, quartz, and glass; the substrate isolation layer 2 is used to isolate the electrical crosstalk between the device and the substrate 1, and includes but is not limited to one or more of silicon dioxide and silicon nitride; the optical waveguide lower cladding 3 is used to limit the transmission of laser to the substrate 1, and includes but is not limited to one or more of silicon dioxide and silicon nitride; the metal reflection layer 6 between the optical waveguide core layer inclined surface structure support layer 4 and the optical waveguide core layer 5 is used to couple the laser from the horizontal direction to the vertical direction, and the metal reflection layer 6 is a metal material with a reflective function, and includes but is not limited to silver, gold, copper, aluminum, chromium, molybdenum, etc.; the optical waveguide core layer inclined surface structure support layer 4 includes but is not limited to one or more of single crystal silicon, silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, and SU-8; the optical waveguide core layer 5 includes but is not limited to one or more of single crystal silicon, silicon nitride, aluminum oxide, and SU-8; the optical waveguide lower cladding 3 and the optical waveguide upper cladding 7 are used to confine the optical waveguide core layer 5 forms an optical field, in other words, the laser is reflected between the optical waveguide lower cladding layer 3 and the optical waveguide upper cladding layer 7 to avoid being transmitted to the substrate 1 and the RF transmission layer 9; the optical waveguide lower cladding layer 3 and the optical waveguide upper cladding layer 7 include but are not limited to one or more of silicon dioxide and silicon nitride; the phase change layer 8 includes but is not limited to a chalcogenide compound or a chalcogenide compound doped with one or more of elements such as indium, hafnium, yttrium, scandium, gallium, titanium, etc., wherein the chalcogenide compound includes but is not limited to germanium telluride, antimony telluride, and germanium antimony telluride; the RF transmission layer 9 includes one or more metal materials with high electrical conductivity such as gold, copper, silver, aluminum, and platinum; the passivation layer 10 is located on the RF transmission layer 9, and the first electrode and the second electrode in the RF transmission layer 9 are exposed outside the passivation layer 10, the first electrode is the input end of the RF signal, and the second electrode is the output end of the RF signal, respectively for receiving and outputting the RF signal, and the passivation layer 10 includes but is not limited to one or more of silicon dioxide, silicon nitride, silicon oxynitride, aluminum oxide, and aluminum nitride.

[0048] It should be noted that the laser-driven phase change RF switch in Example 1 uses an optical waveguide to transmit laser on the chip, and couples the horizontally transmitted laser to the vertical direction through the bevel structure of the metal reflective layer 6, and is incident on the phase change layer 8, so that the phase change layer 8 absorbs energy and undergoes a phase change. When the input is a laser with lower energy and longer pulse width, the phase change layer is transformed into a crystalline state, and the switching functional area composed of the first electrode and the second electrode in the RF transmission layer 9 and the phase change layer 6 is in a low resistance state. At this time, the phase change RF switch is in the on state, allowing the RF signal to pass through with low loss; when the input is a laser with higher energy and shorter pulse width, the phase change layer 8 is transformed into an amorphous state, and the switching functional area composed of the first electrode and the second electrode in the RF transmission layer 9 and the phase change layer 6 is in a high resistance state. At this time, the phase change RF switch is in the off state, blocking the transmission of the RF signal.

[0049] Example 2

[0050] Figure 6 FIG. 1 shows a method for preparing a laser-driven phase-change radio frequency switch according to an embodiment of the present invention. Figure 6 Will combine Figure 1 and Figure 2 The following steps are specifically included:

[0051] S1: Depositing a substrate isolation layer 2 on a substrate 1. Specifically, after cleaning the substrate 1, a plasma enhanced chemical vapor deposition (PECVD) method is used to deposit the substrate isolation layer 2 on the surface of the substrate 1 to prevent the device performance from being affected by leakage and heat conduction problems of the substrate during operation. The substrate 1 includes one or more of silicon, diamond, sapphire, silicon carbide, indium phosphide, gallium arsenide, gallium nitride, quartz, and glass; and the substrate isolation layer 2 is one or more of silicon dioxide, silicon nitride, aluminum nitride, and aluminum oxide.

[0052] S2: depositing an optical waveguide lower cladding layer 3 on the substrate isolation layer 2, using a PECVD method to deposit the optical waveguide lower cladding layer 3 on the substrate isolation layer 2, wherein the optical waveguide lower cladding layer 3 includes but is not limited to one of silicon dioxide, silicon nitride, and SU-8;

[0053] S3: depositing an optical waveguide core layer inclined surface structure support layer 4 on the optical waveguide lower cladding layer 3, depositing the optical waveguide core layer inclined surface structure support layer 4 on the optical waveguide lower cladding layer 3 by a PECVD method, patterning the support layer by a photolithography method, and etching the optical waveguide core layer inclined surface structure support layer 4 with an inclined angle by a sidewall inclined etching process, wherein the angle between the inclined surface end of the optical waveguide core layer inclined surface structure support layer 4 and the optical waveguide lower cladding layer 3 is between 30° and 60°, preferably 45°, and the material of the optical waveguide core layer inclined surface structure support layer 4 includes but is not limited to one or more of single crystal silicon, silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, and SU-8;

[0054] S4: a bevel pattern is produced on the bevel end of the optical waveguide core layer bevel structure support layer 4 in step S3 by photolithography, and metal materials, such as chromium and gold, are sequentially deposited by magnetron sputtering or electron beam evaporation to obtain a metal reflective layer 6, wherein the metal reflective layer 6 is bonded to the bevel end of the optical waveguide core layer bevel structure support layer 4, and the angle between the metal reflective layer 6 and the optical waveguide lower cladding layer 3 is the same as the angle between the bevel end of the optical waveguide core layer bevel structure support layer 4 and the optical waveguide lower cladding layer 3, and the material of the metal reflective layer 6 is a metal material with a reflective function, including but not limited to silver, gold, copper, aluminum, chromium, molybdenum, etc.;

[0055] S5: depositing an optical waveguide core layer material on the metal reflective layer 6 in step S4 by using a PECVD method, and planarizing the upper surface by using chemical mechanical polishing (CMP). A mask pattern of the optical waveguide core layer is obtained by using a photolithography method, and an optical waveguide core layer 5 is obtained by an etching process. The material of the optical waveguide core layer 5 includes but is not limited to one or more of single crystal silicon, silicon nitride, and aluminum oxide.

[0056] S6: depositing an optical waveguide upper cladding 7 on the laser reflective structure composed of the optical waveguide core layer 5, the metal reflective layer 6, and the optical waveguide core layer inclined surface structure support layer 4 and on the optical waveguide lower cladding 3, depositing the optical waveguide upper cladding material on the laser reflective structure by a PECVD method, obtaining a phase change layer pattern by a photolithography method, and obtaining a window structure by etching to obtain the optical waveguide upper cladding 7, wherein the material of the optical waveguide upper cladding 7 includes but is not limited to one of silicon dioxide, silicon nitride, and SU-8;

[0057] S7: depositing a phase change layer 8 on the optical waveguide upper cladding 7, depositing a phase change material on the optical waveguide upper cladding 7 by magnetron sputtering, patterning the phase change material by photolithography, performing mask protection on the phase change material in the window area, etching away the phase change material outside the pattern area by etching, and obtaining the phase change layer 8 after debonding, wherein the phase change layer 8 includes but is not limited to a chalcogenide compound or a chalcogenide compound doped with one or more elements selected from the group consisting of indium, hafnium, yttrium, scandium, gallium, and titanium, wherein the chalcogenide compound includes but is not limited to germanium telluride, antimony telluride, and germanium antimony telluride;

[0058] S8: Depositing radio frequency transmission layer material on the phase change layer 8, and patterning radio frequency transmission electrodes and ground electrodes on the deposited radio frequency transmission layer material by photolithography. Specifically, the radio frequency transmission layer 9 includes a first radio frequency transmission layer 91, a second radio frequency transmission layer 92, and ground electrodes 93 and 94. The first radio frequency transmission layer 91, the second radio frequency transmission layer 92, and the ground electrodes 93 and 94 are in the same plane. Figure 1 Combine Figure 3 and Figure 4 As shown, a first electrode and a second electrode are respectively disposed on a radio frequency transmission layer 91 and a radio frequency transmission layer 92. The first electrode is used to connect to the input end of the radio frequency signal and receive the radio frequency signal. The second electrode is used to connect to the output end of the radio frequency signal and output the radio frequency signal. The ground electrode is used to provide a good electrical connection and reduce interference with the surrounding environment during signal transmission. The first radio frequency transmission layer and the second radio frequency transmission layer are respectively disposed at both ends of the phase change layer, spaced apart. Metal materials, such as chromium and gold thin films, are sequentially deposited by electron beam evaporation. The metal materials outside the photoresist and patterned areas are removed by a wet stripping process. The wet stripping process specifically involves sequentially cleaning with acetone, a stripping solution, isopropyl alcohol, and ultrapure water to obtain a radio frequency transmission layer 9. The material of the radio frequency transmission layer 9 is a metal material, including but not limited to one or more metal materials with high electrical conductivity, such as gold, copper, silver, aluminum, and platinum. The first radio frequency transmission layer and the second radio frequency transmission layer are respectively connected to the phase change layer 8. When the phase change layer 8 is in a high resistance state, the first electrode and the second electrode remain disconnected. Otherwise, the first electrode and the second electrode are connected through the phase change layer 8.

[0059] S9: Deposit the material of the passivation layer 10 on the RF transmission layer 9, use the PECVD method to deposit the passivation layer material, use the photolithography method to pattern the passivation layer material, protect the phase change material area and the RF transmission layer 9, and expose the first electrode and the second electrode in the RF transmission layer 9, etch away the passivation layer material outside the pattern area by etching, and obtain the passivation layer 10 after degumming. The laser-driven phase change RF switch is prepared, wherein the material of the passivation layer 10 includes but is not limited to one or more of silicon dioxide, silicon nitride, silicon oxynitride, aluminum oxide, and aluminum nitride. Figure 6A simplified flow chart for preparing a laser-driven phase-change radio frequency switch is shown.

[0060] Furthermore, in order to verify the excellent performance of the phase-change RF switch of the present invention, the S-parameter simulation of the laser-driven phase-change RF switch of the present invention and the phase-change RF switch of the traditional heating structure was performed in the frequency range of 0 to 220 GHz using HFSS simulation software. The simulation results are shown in Figure 2. Figure 7 and Figure 8 As shown, the insertion loss of a conventional heating-based phase-change RF switch is less than 1dB within 100GHz. Above 100GHz, the insertion loss increases rapidly, preventing RF signals from passing through with low loss. The laser-driven phase-change RF switch exhibits an insertion loss of less than 0.8dB in the 0-220GHz range, demonstrating its low-loss advantage. Simulation results demonstrate that the laser-driven approach significantly reduces RF signal transmission loss and on-state parasitic capacitance.

[0061] The simulation model of the laser-driven phase-change RF switch was established using COMSOL simulation software. In the simulation model, the phase-change layer was selected as the probe domain, and a 50mW laser was applied with a spot radius of 5um. Figure 9 This is the temperature change curve of the phase change layer during the Set process. Within 300ns, the temperature of the phase change layer reaches 476K, which is higher than the crystallization temperature of GeTe phase change material 453K. A 500mW laser is applied with a spot radius of 5um. Figure 10 This is the temperature change curve of the phase change layer during the Reset process. In about 50ns, the phase change layer temperature can reach 998K, which reaches the melting temperature of the GeTe phase change material, and can achieve a fast RESET process. Secondly, compared with the typical electrical operating voltage and pulse width (12V, 200ns) of the traditional microheater structure, the laser-driven structure transmits laser light in a direction through the optical waveguide, which reduces the heat diffusion to the isolation layer and substrate during the driving process of the traditional microheater structure, and has lower power consumption.

[0062] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A laser-driven phase-change radio frequency switch, characterized in that: include: a substrate, located on a semiconductor substrate; a substrate isolation layer, disposed on the substrate; an optical waveguide lower cladding layer, arranged on the substrate isolation layer; a laser reflection structure disposed on the optical waveguide lower cladding, wherein the laser reflection structure comprises an optical waveguide core layer inclined surface structure support layer, an optical waveguide core layer, and a metal reflection layer, wherein the metal reflection layer is disposed between the optical waveguide core layer inclined surface structure support layer and the optical waveguide core layer, wherein the metal reflection layer has an inclined surface structure and is bonded to the inclined surface ends of the optical waveguide core layer inclined surface structure support layer and the inclined surface ends of the optical waveguide core layer; An optical waveguide upper cladding, wherein the laser reflection structure is embedded in the optical waveguide upper cladding and then disposed on the optical waveguide lower cladding, and the top of the optical waveguide upper cladding includes a window structure; A phase change layer is provided in the window structure of the upper cladding of the optical waveguide, and the laser heats the phase change layer by the reflected light of the metal reflective layer, thereby changing the material state of the phase change layer from a high resistance state to a low resistance state or from a low resistance state to a high resistance state; The first RF transmission layer and the second RF transmission layer are arranged on the upper cladding of the optical waveguide, the first RF transmission layer and the second RF transmission layer are on the same horizontal plane, and are respectively arranged at both ends of the phase change layer without contact. When the phase change layer changes from a high-resistance state to a low-resistance state, the first RF transmission layer is connected to the second RF transmission layer; when the phase change layer changes from a low-resistance state to a high-resistance state, the first RF transmission layer and the second RF transmission layer are disconnected. The first electrode in the first RF transmission layer is the input end of the phase change RF switch, and the second electrode in the second RF transmission layer is the output end of the phase change RF switch.

2. The laser-driven phase-change radio frequency switch according to claim 1, characterized in that: The phase change layer is arranged directly above the metal reflective layer, and the metal reflective layer reflects the laser to the phase change layer, changing the material state of the phase change layer, wherein the angle between the metal reflective layer and the lower cladding of the optical waveguide is in the range of 30° to 60°, and the metal reflective layer is made of metal material.

3. The laser-driven phase-change radio frequency switch according to claim 2, characterized in that: The thickness of the phase change layer is smaller than the distance from the top of the upper cladding layer of the optical waveguide to the top of the laser reflection structure.

4. The laser-driven phase-change radio frequency switch according to claim 1, characterized in that: The first end of the first RF transmission layer is provided with a first electrode, and the second end is placed on the phase change layer. The first end of the second RF transmission layer is provided with a second electrode, and the second end is placed on the phase change layer. The first RF transmission layer and the second RF transmission layer are made of metal materials with conductive function.

5. The laser-driven phase-change radio frequency switch according to claim 1, characterized in that: The optical waveguide lower cladding and the optical waveguide upper cladding are used to confine the light field generated by the laser, so that the laser passing through the optical waveguide core is totally reflected between the optical waveguide lower cladding and the optical waveguide upper cladding, wherein the optical waveguide lower cladding and the optical waveguide upper cladding are one or more of silicon dioxide, silicon nitride, and SU-8, and the optical waveguide core is one or more of single crystal silicon, silicon nitride, and aluminum oxide.

6. The laser-driven phase-change radio frequency switch according to claim 1, characterized in that: The substrate includes one or more of silicon, diamond, sapphire, silicon carbide, indium phosphide, gallium arsenide, gallium nitride, quartz, and glass.

7. The laser-driven phase-change radio frequency switch according to claim 1, characterized in that: The substrate isolation layer is one or more of silicon dioxide, silicon nitride, aluminum nitride, and aluminum oxide.

8. The laser-driven phase-change radio frequency switch according to claim 3, characterized in that: The phase change layer is a chalcogenide compound or a chalcogenide compound doped with one or more of indium, hafnium, yttrium, scandium, gallium, and titanium, wherein the chalcogenide compound includes one or more of germanium telluride, antimony telluride, and germanium antimony telluride.

9. The laser-driven phase-change radio frequency switch according to claim 1, characterized in that: It also includes a passivation layer, which is arranged on the first radio frequency transmission layer and the second radio frequency transmission layer and is used to isolate the phase change layer. The passivation layer is one or more of silicon dioxide, silicon nitride, silicon oxynitride, aluminum oxide, and aluminum nitride.

10. A method for preparing a laser-driven phase-change radio frequency switch according to any one of claims 1 to 9, characterized in that: include: S1: Depositing a substrate isolation layer on a substrate by plasma enhanced chemical vapor deposition, wherein the substrate comprises one or more of silicon, diamond, sapphire, silicon carbide, indium phosphide, gallium arsenide, gallium nitride, quartz, and glass; and the substrate isolation layer comprises one or more of silicon dioxide, silicon nitride, aluminum nitride, and aluminum oxide; S2: depositing an optical waveguide lower cladding layer on the substrate isolation layer by plasma enhanced chemical vapor deposition, wherein the optical waveguide lower cladding layer includes one of silicon dioxide, silicon nitride, and SU-8; S3: depositing an optical waveguide core layer inclined surface structure support layer on the optical waveguide lower cladding layer by plasma enhanced chemical vapor deposition, patterning the support layer by photolithography, and etching the optical waveguide core layer inclined surface structure support layer with an inclined angle by sidewall inclined etching process, wherein the angle between the inclined surface end of the optical waveguide core layer inclined surface structure support layer and the optical waveguide lower cladding layer is 30° to 60°, and the material of the optical waveguide core layer inclined surface structure support layer includes one or more of single crystal silicon, silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, and SU-8; S4: using photolithography to produce an inclined surface pattern on the inclined surface end of the optical waveguide core layer inclined surface structure support layer in step S3, and sequentially depositing metal materials by magnetron sputtering or electron beam evaporation to obtain a metal reflective layer, wherein the metal reflective layer is bonded to the inclined surface end of the optical waveguide core layer inclined surface structure support layer, and the angle between the metal reflective layer and the optical waveguide lower cladding layer is the same as the angle between the inclined surface end of the optical waveguide core layer inclined surface structure support layer and the optical waveguide lower cladding layer, and the material of the metal reflective layer is a metal material with a reflective function; S5: depositing an optical waveguide core layer material on the metal reflective layer in step S4 by plasma-enhanced chemical vapor deposition, and planarizing the upper surface by chemical mechanical polishing, obtaining a mask pattern of the optical waveguide core layer by photolithography, and obtaining the optical waveguide core layer by an etching process, wherein the bevel end of the optical waveguide core layer is bonded to the metal reflective layer, and the material of the optical waveguide core layer includes one or more of single crystal silicon, silicon nitride, and aluminum oxide; S6: depositing an optical waveguide upper cladding on the laser reflection structure composed of the optical waveguide core layer, the metal reflection layer, and the optical waveguide core layer inclined surface structure support layer, and the optical waveguide lower cladding, depositing the optical waveguide upper cladding material on the laser reflection structure by plasma enhanced chemical vapor deposition, obtaining a phase change layer pattern by photolithography, obtaining a window structure by etching, and obtaining the optical waveguide upper cladding, wherein the material of the optical waveguide upper cladding comprises one of silicon dioxide, silicon nitride, and SU-8; S7: depositing a phase change layer on the cladding of the optical waveguide, depositing a phase change material on the cladding of the optical waveguide by magnetron sputtering, patterning the phase change material by photolithography, performing mask protection on the phase change material in the window area, etching away the phase change material outside the pattern area by etching, and obtaining the phase change layer after debonding, wherein the phase change layer comprises a chalcogenide compound or a chalcogenide compound doped with one or more elements selected from the group consisting of indium, hafnium, yttrium, scandium, gallium, and titanium, wherein the chalcogenide compound is germanium telluride, antimony telluride, or germanium antimony telluride; S8: depositing a radio frequency transmission layer material on the phase change layer, patterning a first electrode and a second electrode on the deposited radio frequency transmission layer material by a photolithography method, sequentially depositing metal materials by an electron beam evaporation coating method, and removing the photoresist and the metal material outside the patterned area by a wet stripping process, wherein the wet stripping process specifically comprises sequentially cleaning with acetone, a stripping solution, isopropyl alcohol, and ultrapure water to obtain a radio frequency transmission layer, wherein the radio frequency transmission layer includes a first electrode, a second electrode, and a ground electrode, and the material of the radio frequency transmission layer is a metal material; S9: A passivation layer material is deposited on the radio frequency transmission layer using plasma enhanced chemical vapor deposition, the passivation layer material is patterned using photolithography, and the first electrode and the second electrode in the radio frequency transmission layer are exposed, the passivation layer material outside the pattern area is etched away by etching, and the passivation layer is obtained after degumming, wherein the passivation layer material includes one or more of silicon dioxide, silicon nitride, silicon oxynitride, aluminum oxide, and aluminum nitride.

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