Phase change switch with double-layer micro heater and processing technology thereof

Abstract

The invention relates to the field of phase change switches, and provides a phase change switch with a double-layer micro heater in order to solve the problem that an existing phase change switch is difficult to realize high-precision and high-stability regulation and control, and the phase change switch comprises a substrate layer, a bottom micro heating layer, a bottom dielectric layer, a phase change material layer, a phase change layer film electrode, a top dielectric layer and a top micro heating layer which are sequentially overlapped, the bottom micro-heating layer and the top micro-heating layer are connected in parallel; the heating area of the bottom micro-heating layer abuts against the bottom dielectric layer, the heating area of the top micro-heating layer abuts against the top dielectric layer, and the orthographic projection, facing the bottom dielectric layer, of the top dielectric layer completely covers the phase change material layer. According to the invention, a structure which is long in heat path and slow in speed due to the fact that the phase change material permeates from one side to the whole phase change material area by depending on heat conduction in the traditional single-side heating process is improved into a double-layer structure, and simultaneous and symmetrical heating is carried out from two directions, so that the thermal field establishment time is greatly shortened, and the phase change material can be heated to the phase change temperature more quickly.

Description

Technical Field

[0001] This invention relates to the field of phase change switches, and more specifically, to a phase change switch with a double-layer micro heater and its manufacturing process. Background Technology

[0002] Non-volatile phase-change materials, represented by germanium-tellurium (GeTe), play a crucial role in microelectronics and have been increasingly applied in fields such as non-volatile memories, neuromorphic computing, and reconfigurable photonics. The fundamental principle is to utilize GeTe material under external stimulation (usually thermal stimulation) to induce a reversible and rapid phase transition between a crystalline (low-resistivity) and amorphous (high-resistivity) state, thereby enabling information storage or switching of logical states. Existing GeTe-based phase-change switching devices typically include a micro / nano-scale microheater structure. When an electrical pulse is applied to the microheater, it generates Joule heating, which, through thermal radiation, Joule heats the GeTe, bringing the temperature of adjacent GeTe regions to its crystallization temperature or quenching temperature (the temperature at which crystallization transitions to amorphous phase), thus achieving the phase transition of GeTe.

[0003] This traditional phase-change switch heating mode, which uses a single microheater, has inherent and pressing technical drawbacks: 1. Uneven temperature distribution: Because heat is injected from only one side of the GeTe material, a significant temperature gradient is formed within it. The side closer to the heater has the highest temperature, while the side farther away from the heater has a lower temperature. This uneven thermal field causes the phase change process to start from the hot end and gradually spread towards the cold end, which not only reduces the phase change rate but also makes it difficult to precisely control the phase change process (especially the crystallization process), affecting the consistency of device performance. 2. Low energy efficiency: To achieve the overall phase change of GeTe, especially to ensure that the region far from the heater also reaches the phase change threshold temperature, higher power or longer heating pulses are often required. This leads to unnecessary energy loss, with a significant portion of the energy being used to overheat adjacent areas instead of efficiently driving the overall phase change, which contradicts the current trend of low-power electronic devices. 3. Damaged device reliability: The severe temperature gradient induces huge thermal stress within the GeTe material. Under long-term cyclic operation, this can easily lead to failure phenomena such as delamination, voids, or element migration at the material-electrode interface, severely restricting the durability and lifespan of the device.

[0004] The randomness and instability of unilateral heating are the main obstacles to achieving high-precision and high-stability phase transition control. Summary of the Invention

[0005] The purpose of this invention is to provide a phase change switch with a double-layer micro heater and its processing technology, which solves the problem that existing phase change switches are difficult to achieve high-precision and high-stability control, and comprehensively improves speed, energy efficiency, uniformity and reliability.

[0006] The embodiments of the present invention are achieved through the following technical solutions:

[0007] A phase change switch with a double-layer microheater includes a substrate layer, a bottom microheating layer, a bottom dielectric layer, a phase change material layer, a phase change layer thin film electrode, a top dielectric layer, and a top microheating layer, which are stacked sequentially. The bottom microheating layer and the top microheating layer are connected in parallel. The heating area of ​​the bottom microheating layer abuts against the bottom dielectric layer, and the heating area of ​​the top microheating layer abuts against the top dielectric layer. The orthogonal projection of the top dielectric layer toward the bottom dielectric layer completely covers the phase change material layer.

[0008] Preferably, a SiO2 oxide layer is attached to the side of the substrate layer near the bottom micro-heating layer, the thickness of the SiO2 oxide layer is 450-550 nm, and the thickness of the substrate layer is 0.45-0.55 mm.

[0009] Preferably, both the bottom micro-heating layer and the top micro-heating layer include: a heating element and a film layer, with one film layer connected to each end of the heating element. The film layer includes a W film and a Ti film stacked and connected to each other. In the bottom micro-heating layer, the W film is closer to the top micro-heating layer than the Ti film. In the top micro-heating layer, the W film is closer to the bottom micro-heating layer than the Ti film. The thickness of the Ti film is 8-12 nm, and the thickness of the W film is 120-180 nm.

[0010] Preferably, the phase change switch further includes: an input thin-film electrode and an output thin-film electrode; each of the input thin-film electrode and the output thin-film electrode is connected to a film layer of the top micro-heating layer; both the input thin-film electrode and the output thin-film electrode are made of Au thin film, and the thickness of the Au thin film is 500-600 nm.

[0011] Preferably, both the bottom dielectric layer and the top dielectric layer are made of Si3N4 thin film; the thickness of the Si3N4 thin film is 60-80 nm.

[0012] Preferably, the atomic ratio of Ge to Te in the phase change material layer is 58:(40-45), and the thickness of the phase change material layer is 100nm-120nm.

[0013] Preferably, the phase change layer thin film electrode includes: a Pd thin film and an Au thin film stacked together, wherein the Pd thin film is closer to the substrate layer than the Au thin film, the thickness of the Pd thin film is 10-20 nm, and the thickness of the Au thin film is 300-400 nm.

[0014] Preferably, there are two phase change layer thin film electrodes, which are spaced apart and arranged opposite to each other, and the two phase change layer thin film electrodes abut against the phase change material layer.

[0015] Preferably, the phase change switch includes a passivation layer connected to the top micro-heating layer, wherein the passivation layer is a SiO2 thin film.

[0016] A manufacturing process for the phase-change switch includes the following steps:

[0017] S100. An initial bottom micro-heating layer is prepared on the surface of the substrate by magnetron sputtering, and then a bottom micro-heating layer of a preset shape is obtained by photolithography.

[0018] S200: Prepare a Si3N4 thin film as the initial bottom dielectric layer by PECVD, and then obtain the bottom dielectric layer of the preset shape by photolithography and etching processes.

[0019] S300: Ge and Te are deposited on the bottom dielectric layer by magnetron sputtering to obtain an initial phase change material layer, and then a phase change material layer of a predetermined shape is obtained by photolithography.

[0020] S400: An initial phase change layer thin film electrode is prepared by magnetron sputtering, and then a phase change layer thin film electrode of a preset shape is obtained by photolithography.

[0021] S500: A Si3N4 thin film is prepared as the initial top dielectric layer by magnetron sputtering, and then a top dielectric layer of a predetermined shape is obtained by photolithography and etching processes.

[0022] S600: An initial top-layer micro-heating layer is prepared by magnetron sputtering, and then a top-layer micro-heating layer of a preset shape is obtained by photolithography.

[0023] The present invention has at least the following beneficial effects:

[0024] This invention improves the traditional single-sided heating structure, which relies on heat conduction to penetrate the entire phase change material region from one side, resulting in a long and slow heat path, into a double-layer structure that heats simultaneously and symmetrically from two directions. This is equivalent to establishing two heat sources on both sides of the phase change material, which greatly shortens the heat field establishment time and allows the phase change material to be heated to the phase change temperature more quickly. This efficient heating mode reduces the need for long-term high-power supply to a single heater, thus significantly reducing the energy consumption required for the phase change material to switch between low and high resistance. It also improves temperature field uniformity and enhances device reliability: Single-sided heating leads to a large temperature gradient inside the device. This non-uniformity causes localized thermal stress concentration, resulting in interface degradation, voids, or peeling between thin films, which is a major reason for shortening device lifespan. Double-layer symmetrical heating creates a uniform and symmetrical temperature distribution, effectively eliminating excessive temperature gradients and significantly reducing thermal stress. This makes the phase change process smoother and more controllable, fundamentally improving device durability and cycle life. Furthermore, it enables more precise and stable phase change control: The double-layer heater structure provides a more flexible and precise thermal control dimension. By adjusting the shape and size of the upper and lower heaters (i.e., the heating area), the temperature distribution during the phase change process can be shaped. Compared to a single-sided heater with a fixed shape and heating area, the double-sided structure allows for different patterns in the upper and lower layers, enabling the collaborative definition of more complex, diverse, and dynamically matched heating areas, laying the foundation for manufacturing high-performance, low-variability phase change switches. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of a phase changer switch;

[0027] Figure 2 This is an exploded view of a phase changer switch.

[0028] Figure 3 This is a schematic diagram of the first structure of a phase changer;

[0029] Figure 4 This is a schematic diagram of the second structure of a phase change switch;

[0030] Figure 5 This is a schematic diagram of the third structure of a phase-change switch;

[0031] Figure 6 This is a schematic diagram of the fourth structure of a phase-change switch;

[0032] Figure 7 This is a schematic diagram of the fifth structure of a phase-change switch;

[0033] Figure 8 This is a schematic diagram of the sixth structure of a phase-change switch;

[0034] Figure 9 This is a schematic diagram of the seventh structure of a phase change switch;

[0035] Figure 10 This is a schematic diagram of the eighth structure of a phase change switch;

[0036] Figure reference numerals: 1-substrate layer, 2-bottom micro-heating layer, 21-heating element, 22-film layer, 3-bottom dielectric layer, 4-phase change material layer, 5-phase change layer thin film electrode, 6-top dielectric layer, 7-top micro-heating layer, 8-input thin film electrode, 9-output thin film electrode, 10-passivation layer. Detailed Implementation

[0037] To make the objectives, methods, and advantages of the embodiments of the present invention clearer, the methods in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0038] Example 1: As Figure 1-2 As shown, a phase change switch with a double-layer microheater includes a substrate layer, a bottom microheating layer, a bottom dielectric layer, a phase change material layer, a phase change layer thin film electrode, a top dielectric layer, and a top microheating layer, which are stacked sequentially. The bottom microheating layer and the top microheating layer are connected in parallel. The heating area of ​​the bottom microheating layer abuts against the bottom dielectric layer, and the heating area of ​​the top microheating layer abuts against the top dielectric layer. The orthogonal projection of the top dielectric layer toward the bottom dielectric layer completely covers the phase change material layer.

[0039] In specific implementation, the phase change material layer can use existing phase change materials, such as GeTe. The substrate layer can use Si. However, when phase change materials are heated in one direction, they suffer from uneven temperature distribution, low energy efficiency, and reduced durability, which limits their use in high-precision fields requiring high accuracy and speed. Furthermore, to increase the response speed of the phase change switch under unidirectional heating, the phase change material layer is often thin. While reducing the thickness can improve the response speed to some extent, an excessively thin phase change material layer may lead to excessive current density, causing uncontrolled crystallization or breakdown. Therefore, unidirectional heating of phase change materials also affects their design specifications. To address the aforementioned problems, the applicant conceived the technical solution provided by this invention.

[0040] This embodiment uses a double-layer heating system with a bottom micro-heating layer and a top micro-heating layer. The bottom and top dielectric layers simultaneously transfer the Joule heat generated by the micro-heater to GeTe from both top and bottom directions, causing a phase change. In addition, it avoids crosstalk between the pulse drive electrical signal of the micro-heater and the electrical signal passing through GeTe.

[0041] Example 2: In this example, a SiO2 oxide layer is attached to the side of the substrate layer near the bottom micro-heating layer. The thickness of the SiO2 oxide layer is 450-550 nm, and the thickness of the substrate layer is 0.45-0.55 mm.

[0042] In practice, SiO2 can both isolate the phase-change switching device from the Si substrate and conduct excess heat from the bottom micro-heating layer to the Si substrate for heat dissipation.

[0043] Example 3: In this example, both the bottom micro-heating layer and the top micro-heating layer include: a heating element and a film layer. Each end of the heating element is connected to one of the film layers. The film layer includes a W film and a Ti film stacked and connected to each other. In the bottom micro-heating layer, the W film is closer to the top micro-heating layer than the Ti film. In the top micro-heating layer, the W film is closer to the bottom micro-heating layer than the Ti film. The thickness of the Ti film is 8-12 nm, and the thickness of the W film is 120-180 nm.

[0044] In practice, the heating element and the film layer can be made of the same material, and an Au film can also be additionally attached to the heating element. In the bottom micro-heating layer, the Ti film serves as the adhesion layer between the bottom micro-heating layer and SiO2. The W film serves as the conductive functional layer. In the top micro-heating layer, the W film serves as the conductive functional layer of the top micro-heating layer, and the Ti film serves as the adhesion layer between the W film and the input or output thin-film electrode. The film structures of the top and bottom micro-heating layers are mirror-symmetrical.

[0045] Example 4: In this example, the phase change switch further includes: an input thin film electrode and an output thin film electrode; each of the input thin film electrode and the output thin film electrode is connected to a film layer of the top micro heating layer; both the input thin film electrode and the output thin film electrode are made of Au thin film, and the thickness of the Au thin film is 500-600nm.

[0046] Example 5: In this example, both the bottom dielectric layer and the top dielectric layer are Si3N4 thin films; the thickness of the Si3N4 thin film is 60-80 nm.

[0047] In practical implementation, Si3N4 exhibits extremely low interfacial thermal resistance, which significantly reduces thermal boundary resistance, thereby accelerating the crystallization process of the phase change material layer and improving switching speed. Si3N4 is also an extremely dense nitride, effectively blocking the intrusion of oxygen and moisture, preventing oxidation of the phase change material layer surface, and thus maintaining long-term electrical effectiveness. Furthermore, it prevents atoms from the metal electrode from diffusing into the phase change material layer, avoiding performance degradation caused by impurity contamination.

[0048] Example 6: In this example, the atomic ratio of Ge to Te in the phase change material layer is 58:(40-45), and the thickness of the phase change material layer is 100nm-120nm.

[0049] In practical implementation, strictly controlling the atomic ratio of Ge to Te in GeTe phase change materials is crucial for achieving high-performance phase change switches and memories. Although GeTe itself possesses excellent phase change characteristics, even slight compositional deviations can significantly affect its crystallization kinetics, resistivity, and thermal stability. In existing technologies, the most common ratio is 1:1, but this invention adapts this by making the phase change material Ge-enriched, exhibiting extremely fast crystallization kinetics, making the phase change switch suitable for high-frequency operation scenarios. The reason existing technologies struggle to directly use Ge-enriched materials is that their crystallization temperature increases. Given the inherent drawbacks of unidirectional heating, this increased crystallization temperature further limits its application, such as a larger temperature difference across the phase change material layer and lower durability. This invention increases Ge enrichment by employing a bidirectional heating structure, allowing for more uniform heating of the phase change material layer, thus accelerating heat input and compensating for the increased response time caused by the increased crystallization temperature. Furthermore, by introducing an appropriate amount of Te defects, long-range diffusion of Ge atoms during crystallization can be effectively suppressed, thereby reducing grain coarsening and improving device lifespan. The increased crystallization temperature also prevents the phase change switch from accidentally rewriting the material even at higher operating voltages, thus ensuring long-term operational stability.

[0050] Example 7: In this example, the phase change layer thin film electrode includes: a Pd thin film and an Au thin film stacked together, wherein the Pd thin film is closer to the substrate layer than the Au thin film, the thickness of the Pd thin film is 10-20 nm, and the thickness of the Au thin film is 300-400 nm.

[0051] In the specific implementation, the Au film serves as the conductive layer. The Pd film serves as the adhesion and contact layer between the phase change material layer and the conductive layer, reducing the contact resistance between the phase change material layer and the conductive layer.

[0052] Example 8: In this example, there are two phase change layer thin film electrodes. The two phase change layer thin film electrodes are separated by a gap and are arranged opposite each other. The two phase change layer thin film electrodes abut against the phase change material layer.

[0053] Example 9: In this example, the phase change switch includes a passivation layer, which is connected to the top micro-heating layer, and the passivation layer is made of SiO2 thin film.

[0054] In practice, the passivation layer has several functions. Function 1: to provide basic mechanical and environmental protection for the device; Function 2: to prevent heat loss from the top micro-heating layer, ensuring that the bottom and top micro-heating layers are in a symmetrical environment, and guaranteeing that the heat transferred to GeTe from both directions is synchronous and uniform.

[0055] In the top micro-heating layer, the Ti film serves as a passivation layer and an adhesion layer between the Ti film and the W film.

[0056] Implementation 10: This embodiment provides a manufacturing process for the phase-change switch, including the following steps:

[0057] S100. An initial bottom micro-heating layer is prepared on the surface of the substrate by magnetron sputtering, and then a bottom micro-heating layer of a preset shape is obtained by photolithography.

[0058] S200: Prepare a Si3N4 thin film as the initial bottom dielectric layer by PECVD, and then obtain the bottom dielectric layer of the preset shape by photolithography and etching processes.

[0059] S300: Ge and Te are deposited on the bottom dielectric layer by magnetron sputtering to obtain an initial phase change material layer, and then a phase change material layer of a predetermined shape is obtained by photolithography.

[0060] S400: An initial phase change layer thin film electrode is prepared by magnetron sputtering, and then a phase change layer thin film electrode of a preset shape is obtained by photolithography.

[0061] S500: A Si3N4 thin film is prepared as the initial top dielectric layer by magnetron sputtering, and then a top dielectric layer of a predetermined shape is obtained by photolithography and etching processes.

[0062] S600: An initial top-layer micro-heating layer is prepared by magnetron sputtering, and then a top-layer micro-heating layer of a preset shape is obtained by photolithography.

[0063] In the specific implementation process, the applicant designed its processing technology to obtain the phase change switch provided in Examples 1-9. The reason why the bottom dielectric layer and the top dielectric layer use different processes is that the high temperature conditions required in the PECVD preparation process will cause an uncontrollable phase change in the GeTe phase change layer. Therefore, in the preparation of the top dielectric layer, this embodiment adopts the magnetron sputtering process.

[0064] Magnetron sputtering, PECVD, photolithography, and etching are all existing technologies. This embodiment only uses existing technologies to prepare each thin film layer and shape it into a predetermined form. In specific implementation, the process parameters can be adaptively adjusted according to the parameters of each layer to obtain the phase change switch with the specific structure provided in this embodiment. The shapes of each layer can be referred to... Figure 2 The configuration can also be customized as needed. The phase change switch structure provided by this invention only limits the spatial relationship of each layer, the thickness of each layer, and the material.

[0065] The heating elements in the bottom and top micro-heating layers can use the same structure or different structures, as can be seen in the following test examples.

[0066] Example 1: The double-layer heater has a single serpentine structure, and the manufacturing process is as follows:

[0067] 1. Substrate preparation: Si wafer substrate, 0.5 mm thick, with a 500 nm SiO2 oxide layer attached to the surface, and the oxide layer is polished;

[0068] 2. Fabrication of the bottom micro-heating layer: The positive resist stripping process includes photolithography of the micro-heater pattern, fabrication of the micro-heater film and removal of the photoresist. The micro-heating layer film is fabricated using magnetron sputtering. The micro-heating layer film adopts a two-layer film structure. First, a Ti film with a thickness of 10 nm is prepared. Then, a W film with a thickness of 150 nm is prepared on the surface of the Ti film.

[0069] 3. Underlying dielectric layer fabrication: Etching process, including preparing the dielectric layer film, photolithographically patterning the dielectric layer, etching the dielectric layer film, and removing the photoresist. A Si3N4 film with a thickness of 60 nm was prepared using PECVD as the underlying dielectric layer. Microscopic images after step 3 are shown below. Figure 3 ;

[0070] 4. GeTe phase change layer preparation: The process involves photolithography of the GeTe phase change layer pattern, preparation of the GeTe thin film, and removal of the photoresist. GeTe was prepared using magnetron sputtering with a Ge:Te atomic ratio of 58:42. The prepared GeTe thin film was 100 nm thick. Microscopic images after step 3 are shown below. Figure 4 ;

[0071] 5. GeTe phase change layer thin film electrode fabrication: The process involves positive resist stripping, including photolithography of the electrode layer pattern, preparation of the electrode thin film, and removal of the photoresist. The electrode thin film consists of two layers: a bottom layer of Pd film with a thickness of 10 nm and a top layer of Au film with a thickness of 300 nm. Both the Pd and Au films were prepared using magnetron sputtering. A microscope image after step 3 is shown below. Figure 5 ;

[0072] 6. Top dielectric layer preparation: Etching process, including preparation of dielectric layer film, photolithography of dielectric layer pattern, etching of dielectric layer film and removal of photoresist. A Si3N4 thin film is prepared as the top dielectric layer film using magnetron sputtering process, and the thickness of the prepared dielectric layer film is 60 nm.

[0073] 7. Preparation of the top micro-heating layer: The positive resist stripping process includes photolithography of the micro-heater pattern, preparation of the micro-heater film and removal of the photoresist. The micro-heating layer film is prepared by magnetron sputtering. The micro-heating layer film adopts a two-layer film structure. The thickness of the W film is 150 nm. Then, a Ti film with a thickness of 10 nm is prepared on the surface of the W film.

[0074] 8. Fabrication of thin film electrodes at the input and output ends of the micro heater: positive photoresist stripping process, including photolithography of electrode layer pattern, preparation of electrode thin film and removal of photoresist. Au thin film is used as the thin film electrode at the input and output ends of the micro heater, and the thickness of the Au thin film is 500 nm.

[0075] 9. Passivation Layer Fabrication: The etching process includes fabricating the passivation layer film, photolithographically patterning the passivation layer, etching the passivation layer film, and removing the photoresist. A SiO2 film with a thickness of 500 nm was prepared using magnetron sputtering as the passivation layer. A microscopic image of the completed phase-change switch is shown below. Figure 6 .

[0076] Experimental Example 2: The double-layer heater has a structure of two parallel serpentine roots.

[0077] The difference from Example 1 is that a dual-parallel serpentine patterned photolithographic microheater was selected in steps 2 and 7. The remaining fabrication steps were the same as in Example 1. A microscopic image of the completed phase-change switch is shown below. Figure 7 .

[0078] Experimental Example 3: The double-layer heater has a corrugated structure.

[0079] The difference from Example 1 is that a wavy patterned photolithographic microheater was selected in steps 2 and 7, while the remaining fabrication steps were the same as in Example 1. A microscopic image of the completed phase-change switch is shown below. Figure 8 .

[0080] Experimental Example 4: The double-layer heater has a structure of two parallel straight rods.

[0081] The difference from Example 1 is that a dual-parallel linear patterned photolithography microheater was selected in steps 2 and 7. The remaining fabrication steps were the same as in Example 1. A microscopic image of the completed phase-change switch is shown below. Figure 9 .

[0082] Experimental Example 5: The double-layer heater has a battlement-shaped structure.

[0083] The difference from Example 1 is that a battlement-shaped patterned photolithographic microheater was selected in steps 2 and 7. The remaining processing steps were the same as in Example 1. A microscopic image of the completed phase-change switch is shown below. Figure 10 .

[0084] The test results for the experimental cases are shown in Table 1.

[0085] Table 1

[0086] Test Case Number Double-layer heater resistance value On-off switching pulse voltage peak On-off switching pulse width Corresponding pulse width for single-layer heater on / off switching Off-on switching pulse voltage peak Off-on switching pulse width Corresponding single-layer heater on / off switching pulse width 1 55.3 Ω 40 V 50 ns 80 ns 12 V 2 μs 6.2 μs 2 21.7 Ω 20 V 50 ns 60 ns 8 V 2 μs 4.8 μs 3 67.3 Ω 47 V 50 ns 90 ns 15 V 2 μs 8 μs 4 14.6 Ω 15 V 50 ns 80 ns 6 V 2 μs 4 μs 5 26.4 Ω 35 V 50 ns 100 ns 8 V 2 μs 9.6 μs

[0087] Test Description: A probe station is used to apply a pulse voltage signal to the double-layer heater section of the device. The pulse width (pulse time) of the pulse voltage is fixed. By adjusting the peak value of the pulse voltage, the GeTe phase change layer is excited to undergo a phase change, thereby realizing the switching between the "on" and "off" states of the device.

[0088] The experimental data corresponding to the single-layer heater are from a phase-change switch with a single-layer micro-heater. The difference in structure between this switch and the corresponding experimental example is the absence of a top dielectric layer and a top micro-heating layer. The experiment used the peak pulse voltage for switching with a double-layer heater, and the device switching was achieved by adjusting the pulse width. The experimental data shows that, under the same peak pulse voltage, the single-layer heater device requires a wider pulse width for switching than the double-layer heater device. This phenomenon is more pronounced when switching from the "off" to the "on" state. Switching from the "off" to the "on" state requires sufficient heat accumulation to transform GeTe from an amorphous state to a crystalline state, while switching from the "on" to the "off" state only requires quenching of GeTe. Therefore, the heater structure has a greater impact on the switching process from the "off" to the "on" state.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A phase change switch having a double layer micro-heater, characterized in that, The substrate layer, the bottom micro-heating layer, the bottom dielectric layer, the phase change material layer, the phase change layer thin film electrode, the top dielectric layer and the top micro-heating layer are sequentially overlapped. The bottom micro-heating layer and the top micro-heating layer are connected in parallel. The heating area of the bottom micro-heating layer is in abutment with the bottom dielectric layer, the heating area of the top micro-heating layer is in abutment with the top dielectric layer, and the top dielectric layer is completely overlapped with the phase change material layer in orthographic projection towards the bottom dielectric layer.

2. The phase change switch of claim 1, wherein, The side of the substrate layer close to the bottom micro-heating layer is attached with a SiO2 oxide layer, the thickness of the SiO2 oxide layer is 450-550 nm, and the thickness of the substrate layer is 0.45-0.55 mm.

3. The phase change switch of claim 1, wherein, The bottom micro-heating layer and the top micro-heating layer each comprise a heating element and a film layer, the two ends of the heating element are connected with one of the film layers respectively, the film layer comprises a W thin film and a Ti thin film which are connected with each other in layers, the W thin film in the bottom micro-heating layer is closer to the top micro-heating layer than the Ti thin film, the W thin film in the top micro-heating layer is closer to the bottom micro-heating layer than the Ti thin film, the thickness of the Ti thin film is 8-12 nm, and the thickness of the W thin film is 120-180 nm.

4. The phase change switch of claim 3, wherein, Further comprising: An input thin film electrode and an output thin film electrode, the input thin film electrode and the output thin film electrode are connected with one of the film layers of the top micro-heating layer respectively, the input thin film electrode and the output thin film electrode each adopt an Au thin film, and the thickness of the Au thin film is 500-600 nm.

5. The phase change switch of claim 1, wherein, The bottom dielectric layer and the top dielectric layer each adopt an Si3N4 thin film, and the thickness of the Si3N4 thin film is 60-80 nm.

6. The phase change switch of claim 1, wherein, The atomic number ratio of target material Ge to Te in the phase change material layer is 58: (40-45), and the thickness of the phase change material layer is 100-120 nm.

7. Phase change switch according to any of claims 1-6, characterized in that The phase change layer thin film electrode comprises a Pd thin film and an Au thin film which are connected with each other in layers, the Pd thin film is closer to the substrate layer than the Au thin film, the thickness of the Pd thin film is 10-20 nm, and the thickness of the Au thin film is 300-400 nm.

8. The phase change switch of claim 7, wherein, The phase change layer thin film electrode has two, the two phase change layer thin film electrodes are arranged oppositely with a gap therebetween, and the two phase change layer thin film electrodes are in abutment with the phase change material layer.

9. The phase change switch of claim 7, wherein, Further comprising: A passivation layer, the passivation layer is connected with the top micro-heating layer, and the passivation layer adopts an SiO2 thin film.

10. A process for the production of a phase change switch according to any one of claims 1 to 9, characterized in that Comprising the following steps: S100, preparing an initial bottom micro-heating layer on the surface of a substrate layer by a magnetron sputtering process, and then obtaining a bottom micro-heating layer with a preset shape by a photoetching process; S200, preparing an Si3N4 thin film as an initial bottom dielectric layer by a PECVD, and then obtaining a bottom dielectric layer with a preset shape by a photoetching process and an etching process; S300, depositing Ge and Te on the bottom dielectric layer by a magnetron sputtering process to obtain an initial phase change material layer, and then obtaining a phase change material layer with a preset shape by a photoetching process; S400, preparing an initial phase change layer thin film electrode by a magnetron sputtering process, and then obtaining a phase change layer thin film electrode with a preset shape by a photoetching process; S400, preparing an initial phase change layer thin film electrode by a magnetron sputtering process, and then obtaining a phase change layer thin film electrode with a preset shape by a photoetching process; S500, preparing Si3N4 thin film as an initial top layer dielectric layer by a magnetron sputtering process, and then obtaining a top layer dielectric layer with a preset shape by a photoetching process and an etching process; S600, preparing an initial top layer micro-heating layer by a magnetron sputtering process, and then obtaining a top layer micro-heating layer with a preset shape by a photoetching process.

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