A phase-change photonic device and a method of manufacturing the same

Abstract

The application provides a phase-change photonic device and a preparation method thereof, and relates to the technical field of semiconductors.The preparation method of the phase-change photonic device in the application is as follows: a ridge-type silicon waveguide is prepared; a phase-change material layer is prepared on the surface of the ridge-type silicon waveguide; then, in sequence, a laser is used to irradiate the surface of the initial phase-change photonic device with short pulses of different energy values in stages, so that the phase-change material layer is gradually cooled in sequence, and the microstructure of the phase-change material layer is adjusted in the gradual cooling process, the phase-change photonic synaptic weight is changed, and the final phase-change photonic device is obtained.Based on this, the phase-change material layer on the ridge-type silicon waveguide is irradiated in sequence by using multi-stage combined pulses, so that the phase-change material layer is gradually cooled in sequence, and the microstructure of the phase-change material layer is adjusted in the gradual cooling process, and the phase-change photonic synaptic weight is changed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a phase-change photonic device and a preparation method thereof. BACKGROUND

[0002] In recent years, phase-change materials have made significant progress in cutting-edge applications such as photonic neural networks, photonic weight banks, and convolution accelerators, showing great application potential. The weight performance of photonic synapses directly affects the accuracy of matrix multiplication, as well as the speed and energy consumption related to weight updates. Its performance is mainly restricted by two factors: one is the material properties of the device, and the other is the modulation method. Generally, the maximum theoretical optical contrast and phase change speed of the device are improved mainly by improving the modulation method.

[0003] Existing modulation methods are mainly divided into two categories: electrical modulation and optical modulation. Although optical modulation can reduce the heat diffusion loss caused by the electrical modulation process, the change in atomic arrangement during the corresponding phase change in optical modulation will cause a change in the material band gap, which will significantly affect the absorption efficiency of pump light energy, posing a major obstacle to achieving accurate optical modulation. At the same time, the crystallization rate of most phase-change materials exhibits significant non-Arrhenius temperature dependence. For example, in a typical Ge2Sb2Te5 (GST) material, the crystallization rate can vary by as much as 9 orders of magnitude in the range from the crystallization temperature to the melting temperature. Too low or too high a temperature will hinder the formation of effective crystals. The heating and cooling rate of the phase-change material is also closely related to its final crystal structure and quality. After several phase change cycles, the material may experience element segregation, mainly due to stress effects and thermal gradients during the crystallization process, thereby gradually degrading the performance of the device.

[0004] Therefore, there is an urgent need for a phase-change photonic device scheme that can overcome the shortcomings of the existing phase-change photonic device photoelectric modulation method, adjust the weight performance of the photonic synapse, and improve the accuracy of matrix multiplication. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a phase-change photonic device and a preparation method thereof, which can improve the weight performance of the photonic synapse and improve the accuracy of matrix multiplication.

[0006] In a first aspect, the present application provides a preparation method of a phase-change photonic device, which comprises the following steps for any phase-change photonic device:

[0007] Preparation of a ridge-type silicon waveguide;

[0008] Preparation of a phase-change material layer on the surface of the ridge-type silicon waveguide to obtain an initial phase-change photonic device; wherein the phase-change material layer covers the ridge-type silicon waveguide;

[0009] In the stage sequence, the laser outputs short pulses with different energy values in each pulse irradiation stage, and the surface of the initial phase-change photonic device is irradiated in sequence to gradually reduce the temperature of the phase-change material layer in the stage sequence, and adjust the microstructure of the phase-change material layer in the process of gradually reducing the temperature, change the phase-change photonic synapse weight, and obtain the final phase-change photonic device.

[0010] The time length corresponding to each pulse irradiation stage is different.

[0011] Optionally, according to the stage sequence, the initial pulse irradiation stage is the first pulse irradiation stage, and the step of irradiating the surface of the initial phase-change photonic device in sequence by the laser outputting short pulses with different energy values in each pulse irradiation stage includes:

[0012] In the first pulse irradiation stage, the laser outputs a first pulse segment to heat the phase-change material layer to melt the phase-change material in the phase-change material layer; wherein the first pulse segment includes at least one short pulse with the same energy value.

[0013] In the remaining pulse irradiation stages except the first pulse irradiation stage, the laser outputs a corresponding pulse segment to heat the phase-change material layer to adjust the temperature of the phase-change material to a preset temperature range, so that the phase-change material layer is in a microstructure switching state.

[0014] The mean value of the preset temperature range is less than the melting temperature of the phase-change material.

[0015] Optionally, the mean value of the preset temperature range is equal to 350℃.

[0016] Optionally, for any pulse irradiation stage, the step of irradiating the surface of the initial phase-change photonic device in sequence by the laser outputting short pulses with different energy values in each pulse irradiation stage includes:

[0017] In the current pulse irradiation stage, the laser applies a plurality of short pulses with the same energy to the phase-change material layer above the initial phase-change photonic device in sequence at a first preset time interval.

[0018] The energy corresponding to each pulse irradiation stage gradually decreases in the stage sequence.

[0019] Optionally, the first preset time interval is less than or equal to 30 ns.

[0020] Optionally, when the first pulse irradiation stage, the second pulse irradiation stage and the third pulse irradiation stage are sequentially included in time sequence, the pulse energies corresponding to the first pulse irradiation stage, the second pulse irradiation stage and the third pulse irradiation stage are the first pulse energy, the second pulse energy and the third pulse energy in sequence; the time intervals corresponding to the first pulse irradiation stage, the second pulse irradiation stage and the third pulse irradiation stage are the first time interval, the second time interval and the third time interval in sequence; the step of irradiating the surface of the initial phase change photonic device in sequence by using the laser to output short pulses with different energy values in each pulse irradiation stage comprises:

[0021] In the first pulse irradiation stage, a short pulse corresponding to a first pulse energy value is continuously output by the laser in a first preset time interval to irradiate the phase change material layer;

[0022] In the second pulse irradiation stage, short pulses corresponding to a plurality of second pulse energy values are sequentially output by the laser in a second preset time interval to irradiate the phase change material layer;

[0023] In the third pulse irradiation stage, short pulses corresponding to a plurality of third pulse energies are sequentially output by the laser in a third preset time interval to irradiate the phase change material layer;

[0024] Optionally, the second pulse energy value is less than the first pulse energy value and greater than the third pulse energy value.

[0025] Optionally, the end time of the first pulse irradiation stage is the same as the start time of the second pulse irradiation stage; and the second pulse irradiation stage and the third pulse irradiation stage have a second preset time interval.

[0026] Optionally, the second time interval is 20 ns.

[0027] Optionally, along the direction of the ridge waveguide, the length of the phase change material layer is 4 μm and the thickness is 30 nm.

[0028] In a second aspect, the application further provides a phase change photonic device, which is prepared by the preparation method of any one of the first aspect.

[0029] The phase change photonic device and the preparation method thereof provided by the application have the following beneficial effects:

[0030] The preparation method of the phase-change photonic device in the application is as follows: preparing a ridge-type silicon waveguide; and preparing a phase-change material layer on the surface of the ridge-type silicon waveguide to obtain an initial phase-change photonic device; wherein the phase-change material layer covers the optical waveguide layer; then, according to the order of stages, using a laser to irradiate the surface of the initial phase-change photonic device with short pulses of different energy values in each stage to gradually cool the phase-change material layer according to the order of stages and adjust the microstructure of the phase-change material layer in the process of gradual cooling, change the phase-change photonic synaptic weight, and obtain a final phase-change photonic device; wherein the time length corresponding to each pulse irradiation stage is different. Based on this, the phase-change material layer on the ridge-type silicon waveguide is irradiated by the multi-stage combined pulse in each stage in turn, so that the phase-change material layer is gradually cooled according to the order of stages, and the microstructure of the phase-change material layer is adjusted in the process of gradual cooling, the phase-change photonic synaptic weight is changed, and then the shortcomings in the optical-electricity modulation method of the phase-change photonic device in the prior art are overcome, and the modulation depth, precision, speed and energy efficiency of the photonic device are improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments of the application. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0032] Figure 1 The step flow chart of the preparation method of the phase-change photonic device provided in the embodiments of the application is shown in the following figure:

[0033] Figure 2 The sub-step flow chart of step 200 in the embodiments of the application is shown in the following figure:

[0034] Figure 3 The cross-sectional structure diagram corresponding to the preparation of the ridge-type silicon waveguide in the embodiments of the application is shown in the following figure:

[0035] Figure 4 The cross-sectional structure diagram corresponding to the preparation of the phase-change material layer in the embodiments of the application is shown in the following figure:

[0036] Figure 5 The cross-sectional structure diagram corresponding to the preparation of the phase-change material layer in the embodiments of the application is shown in the following figure:

[0037] Figure 6 The cross-sectional structure diagram corresponding to the preparation of the phase-change material layer in the embodiments of the application is shown in the following figure:

[0038] Figure 7 The sub-step flow chart of step 300 in the embodiments of the application is shown in the following figure:

[0039] Figure 8 (I) is a device test diagram of a phase-change photonic device in an embodiment of the present application; a

[0040] Figure 8 (II) is a device test diagram of a phase-change photonic device in an embodiment of the present application; b

[0041] Figure 8 (III) is a device test diagram of a phase-change photonic device in an embodiment of the present application. c

[0042] Figure legend: 10 - substrate; 11 - ridge silicon waveguide; 12 - phase-change material layer; 13 - protective layer; 14 - thermal isolation layer. DETAILED DESCRIPTION

[0043] As described in the background, the weight performance of the photonic synapse directly affects the accuracy of matrix multiplication, as well as the speed and energy consumption related to weight update. The prior art often uses electrical modulation and optical modulation to modulate the phase-change material, in order to improve the modulation contrast, accuracy, speed, linearity of the device, while reducing the modulation capacity.

[0044] Compared with electrical modulation, optical modulation does not require additional heating electrode structure, and can directly heat the device using high instantaneous power laser pulses, further improving the modulation speed and significantly reducing the heat diffusion loss in the modulation process. However, due to the stress effect and thermal gradient in the crystallization process, the material may experience element segregation after multiple phase change cycles, causing the device performance to gradually decline. Based on this, the present application provides a phase-change photonic device and a preparation method to overcome the above technical problems.

[0045] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

[0046] Reference Figure 1 , Figure 1 is a step flowchart of the preparation method of the phase-change photonic device provided in an embodiment of the present application, wherein for any phase-change photonic device, the preparation method includes step 100 and step 300.

[0047] Step 100, preparing a ridge silicon waveguide.

[0048] Step 200, preparing a phase-change material layer on the surface of the ridge silicon waveguide to obtain an initial phase-change photonic device.

[0049] The phase-change material layer covers the optical waveguide layer.

[0050] ​​​Step 300, in the phase sequence, a laser is used to irradiate short pulses of different energy values pulse by pulse, and the surface of the initial phase-change photonic device is irradiated in sequence, so that the phase-change material layer is gradually cooled in the phase sequence, and the microstructure of the phase-change material layer is adjusted in the gradual cooling process, the phase-change photonic synapse weight is changed, and the final phase-change photonic device is obtained.

[0051] Wherein, the time length corresponding to each pulse irradiation stage is different.

[0052] In this embodiment, a phase-change material layer is prepared on a ridge-type silicon waveguide, and then the surface of the initial phase-change photonic device, especially the phase-change material layer, is irradiated in stages by using a laser to output combined pulses, that is, different energy pulses are combined to realize combined pulse instead of the traditional two-step pulse modulation scheme, so that the phase-change material layer is gradually cooled in the phase sequence, the non-Arrhenius crystallization characteristics of the phase-change material are fully utilized, the crystallization characteristics are improved, and the formation of effective crystals is avoided. The temperature is too low or too high; and in the gradual cooling process, the microstructure of the phase-change material layer is adjusted, that is, the switching state between the two microstructures of amorphous and crystal, for example, in the coexistence stage of the amorphous state and the crystal state of the phase-change material in the gradual cooling process, the transmittance of the current phase-change photonic device is converted between the maximum transmittance Tmax and the minimum transmittance Tmin, and then the adjustment of the phase-change photonic synapse weight is realized, and the final phase-change photonic device is obtained.

[0053] Based on this, based on the multi-stage slow cooling characteristics of the crystallization process of the phase-change material, the combined pulse modulation method is set, which can more energy-saving and stable amorphous erasing, while inhibiting the switching between multiple crystal structures, improving the synaptic programmable state number precision and linearity of the phase-change photonic device, and optimizing the weight configuration in the neural network.

[0054] Please refer to Figure 1 on the basis of Figure 2 , Figure 2 The step flow chart of step 100 in this embodiment is shown, and the step 100 of preparing a ridge-type silicon waveguide in this embodiment includes the following steps:

[0055] Step 101, providing a substrate.

[0056] Step 102, setting a ridge-type silicon waveguide on the substrate.

[0057] Please refer to Figure 2 on the basis of Figure 3 , Figure 3Fig. 1 shows a cross-sectional view of the ridge-type silicon waveguide after the step 100. In this embodiment, the optical waveguide can be prepared on a SOI substrate 10 (Silicon-On-Insulator). For example, the SOI substrate can be patterned and etched by electron beam lithography to obtain a ridge-type silicon waveguide 11.

[0058] Based on the above, referring to Figure 3 , Figure 4 , Figure 4 Fig. 2 shows another cross-sectional view of the ridge-type silicon waveguide after the step 200. After the preparation of the phase-change material layer 12, a protective layer 13 can be prepared on the surface of the phase-change material layer 12 to avoid oxidation during the modulation. The protective layer 13 can also be formed by ultraviolet lithography and magnetron sputtering deposition.

[0059] In one possible implementation, the Ge2Sb2Te5 material can be directly deposited on the optical waveguide by a magnetron sputtering system, and then patterned by ultraviolet lithography to obtain the phase-change material layer 12. In another possible implementation, based on the above, referring to Figure 4 , Figure 5 , Figure 5 Fig. 2 shows another cross-sectional view of the ridge-type silicon waveguide after the step 200. After the preparation of the phase-change material layer 12, a protective layer 13 can be prepared on the surface of the phase-change material layer 12 to avoid oxidation during the modulation. The protective layer 13 can also be formed by ultraviolet lithography and magnetron sputtering deposition.

[0060] In this embodiment, the length of the phase-change material layer 12 is 4 μm, and the thickness is 30 nm. Further, the width of the phase-change material layer 12 is slightly wider than the width of the ridge-type waveguide.

[0061] In another possible implementation, to avoid heat leakage and to avoid large loss of optical signals during transmission, which affects the efficiency of the device, a thermal isolation layer 14 can also be provided on the phase-change material layer. The thermal isolation layer 14 covers the optical waveguide layer, i.e., the surface of the ridge-type silicon waveguide 11, and the width of the thermal isolation layer 14 is greater than or equal to the width of the optical waveguide layer. Please refer to Figure 6 , Figure 6 Fig. 2 shows another cross-sectional view of the ridge-type silicon waveguide after the step 200. After the preparation of the phase-change material layer 12, a protective layer 13 can be prepared on the surface of the phase-change material layer 12 to avoid oxidation during the modulation. The protective layer 13 can also be formed by ultraviolet lithography and magnetron sputtering deposition.

[0062] In this embodiment, the material of the thermal isolation layer is a material containing nanoscale low thermal conductivity, such as silicon oxide (SiO2), stainless steel, titanium alloy, silicon nitride (Si3N 4）Any one of the materials with low thermal conductivity and thermal stability, such as aluminum oxide (Al2O3), boron nitride (BN), microporous nanometer separation (Cr), graphene (C), and Al-B-O system compounds.

[0063] Please fill in Figure 1 on the basis of Figure 7 , Figure 7 A sub-step flow chart of step 300 in the embodiment is shown, and step 300 of the final phase-change photonic device in the embodiment includes steps 301 and 302.

[0064] Step 301: In the first pulse irradiation stage, a first pulse segment is output by the laser to heat the phase-change material layer to melt the phase-change material in the phase-change material layer.

[0065] The first pulse segment includes at least one short pulse with the same energy value.

[0066] Step 302: In the remaining pulse irradiation stages other than the first pulse irradiation stage, corresponding pulse segments are output by the laser to heat the phase-change material layer to adjust the temperature of the phase-change material to a preset temperature range, so that the phase-change material layer is in a microstructure switching state.

[0067] The average value of the preset temperature range is less than the melting temperature of the phase-change material.

[0068] In the embodiment, spatially pumped light can be used to construct a combined pulse, and then the phase-change material layer is irradiated in stages. In the first pulse irradiation stage, high pulse energy can be preferentially output to heat the device temperature above the material melting temperature, for example, above 600 degrees Celsius, so as to facilitate crystallization of the phase-change material. In other irradiation stages other than the first pulse irradiation stage, the device temperature is gradually reduced, so that the phase-change material switches between amorphous and crystalline microstructures.

[0069] In the embodiment, the device temperature in the other irradiation stages other than the first pulse irradiation stage can be maintained in an optimal crystallization range, for example, 350 degrees Celsius, which is the average value of the above-mentioned preset temperature range, to achieve adjustment of the phase-change photonic synapse weight.

[0070] In the embodiment, for any pulse irradiation stage, the laser outputs short pulses with different energy values for each pulse irradiation stage, and the steps of sequentially irradiating the surface of the initial phase-change photonic device are as follows:

[0071] In the current pulse irradiation stage, the laser applies a plurality of short pulses with the same energy to the phase-change material layer from above the initial phase-change photonic device according to a first preset time interval.

[0072] The energy gradually decreases for each pulse irradiation stage in the sequential order.

[0073] In one possible implementation, in any pulse irradiation stage, a 1550 nm laser can be used as a pump light source to output short pulses with the same energy according to a first time interval, and irradiate the surface of the phase change photonic device vertically from above the device to modulate.

[0074] For example, in the first pulse irradiation stage, a first pulse segment with a pulse energy of 84 pJ (i.e., the first pulse energy described below) can be used to heat the phase change material layer to melt the phase change material in the phase change material layer.

[0075] The first pulse segment can include one short pulse. If the first pulse segment includes multiple short pulses, there is a certain time interval between the output times of the short pulses, i.e., the first time interval. The first time interval can be 20 ns.

[0076] Based on this, the high-energy pump light pulse used in the first pulse irradiation stage can heat the phase change material to the melting temperature, and due to the rapid annealing process, the amorphous state will remain disordered. Subsequently, the phase change material is heated above the crystallization temperature for a period of time based on low-energy pump light, thereby reordering the atoms to the crystalline state.

[0077] Based on the above steps, an embodiment is provided to fully demonstrate the preparation method provided by the present application.

[0078] After the initial phase change photonic device is prepared according to steps 100 to 200, the first pulse irradiation stage, the second pulse irradiation stage, and the third pulse irradiation stage are sequentially included in time order, and the pulse energies corresponding to the first pulse irradiation stage, the second pulse irradiation stage, and the third pulse irradiation stage are the first pulse energy, the second pulse energy, and the third pulse energy, respectively. The time intervals corresponding to the first pulse irradiation stage, the second pulse irradiation stage, and the third pulse irradiation stage are the first time interval, the second time interval, and the third time interval, respectively. In this embodiment, the laser outputs short pulses with different energy values for each pulse irradiation stage, and the surface of the initial phase change photonic device is irradiated in sequence. Step 300 is specifically:

[0079] In the first pulse irradiation stage, the laser continuously outputs a short pulse corresponding to the first pulse energy value in the first preset time interval to irradiate the phase change material layer.

[0080] In the second pulse irradiation stage, the laser outputs multiple short pulses corresponding to the second pulse energy value in the second preset time interval to irradiate the phase change material layer.

[0081] In the third pulse irradiation stage, the laser is used to output a plurality of short pulses corresponding to third pulse energy values in a third preset time interval, and the phase change material layer is irradiated.

[0082] The second pulse energy value is less than the first pulse energy value and greater than the third pulse energy value.

[0083] In this embodiment, the first pulse irradiation stage has a time length of 20 ns. Based on this, the embodiment can output a light pulse with a pulse energy of 84 pJ to act on the surface of the phase change photonic device in the 0-20 ns stage.

[0084] Subsequently, the second pulse irradiation stage can be directly entered at the end time of the first pulse irradiation stage, that is, the end time of the first pulse irradiation stage is the same as the start time of the second pulse irradiation stage. The pulse energy corresponding to the second pulse irradiation stage in this embodiment can be 67 pJ. To ensure the temperature stability of the step-by-step cooling process, a plurality of light pulses with the same pulse energy and a certain time interval can be output. In addition, the time length of the second pulse irradiation stage in this embodiment can be 60 ns, that is, the embodiment can output a plurality of light pulses with a pulse energy of 67 pJ to act on the surface of the phase change photonic device in the 20-80 ns stage, and the interval time of each light pulse is 20 ns.

[0085] Similarly to the above steps, the time length of the third pulse irradiation stage can be 120 ns, and the pulse energy corresponding to the third pulse irradiation stage can be 56 pJ, that is, the embodiment can output a plurality of light pulses with a pulse energy of 56 pJ to act on the surface of the phase change photonic device in the 80-200 ns stage, and the interval time of each light pulse is 20 ns.

[0086] In another possible implementation manner, to ensure the temperature stability of the phase change material crystallization process in combination with the multi-stage slow cooling characteristics of the phase change material crystallization process, a certain time interval, for example, 20 ns, can exist between the third pulse irradiation stage and the third pulse irradiation stage.

[0087] Based on this, the application can use light pulses with short time intervals and high energy and a modulation scheme with sequentially decreasing energy to suppress the element segregation caused by the temperature gradient and the non-uniform stress in the crystallization process, and greatly improve the durability of the device.

[0088] Based on the same inventive concept, the embodiment of the application also provides a phase change photonic device, which is made by the preparation method in any one of the first aspect.

[0089] In addition, refer to FIG. 8( a ), FIG. 8( b ), FIG. 8( c ), FIG. 8( a ) is a state diagram of a photonic device containing phase change materials with different thicknesses under combined pulse modulation; FIG. 8( b ) is a durability and stability test diagram of a phase change photonic device under combined pulse modulation; FIG. 8( c ) is a programming state number precision and linearity test diagram of a phase change photonic device under combined pulse modulation. As can be seen from FIG. 8( a ), FIG. 8( b ), FIG. 8( c ), the phase change photonic device prepared in the present application has the following beneficial effects:

[0090] 1. High light absorption contrast. Based on a 4 μm long and 30 nm thick phase change material unit overlaid on a straight waveguide, the device transmission contrast can reach 31.2 dB.

[0091] 2. High time and energy efficiency of device crystallization operation. The total time required for complete crystallization of the device is 200 ns, and the energy is 107 pJ.

[0092] 3. High durability of the device. After 108 cycles of crystallization and amorphization for state writing and erasing, the device can still work normally.

[0093] 4. High linearity of device programming. The weight state of the device has good linearity in multiple programming.

[0094] Based on the same inventive concept, the present application also provides a phase change photonic device, which is prepared by the preparation method of any one of the first aspect.

[0095] In summary, the phase change photonic device and the preparation method thereof in the present application, wherein for any phase change photonic device, the preparation method comprises the following steps: preparing a ridge-type silicon waveguide; and preparing a phase change material layer on the surface of the ridge-type silicon waveguide to obtain an initial phase change photonic device; wherein the phase change material layer covers the optical waveguide layer; then, according to the order of stages, a laser is used to irradiate short pulses with different energy values in each stage to irradiate the surface of the initial phase change photonic device in turn, so that the phase change material layer is gradually cooled according to the order of stages, and the microstructure of the phase change material layer is adjusted in the process of gradual cooling, the phase change photonic synaptic weight is changed, and the final phase change photonic device is obtained; wherein the time length corresponding to each pulse irradiation stage is different.

[0096] Based on this, the application uses multi-stage combined pulse to irradiate the phase change material layer on the ridge silicon waveguide in stages, so that the phase change material layer is gradually cooled according to the stage order, and the microstructure of the phase change material layer is adjusted in the gradual cooling process, the phase change photonic synapse weight is changed, and then the deficiencies in the optical and electrical modulation method of the existing phase change photonic device are overcome, and the modulation depth, precision, speed and energy efficiency of the photonic device are improved.

[0097] In the embodiments provided by the present application, it should be understood that the disclosed device and method can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There can be another division during actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between the units can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical, mechanical or in other forms.

[0098] In addition, the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiments.

[0099] Furthermore, the function modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0100] It should be noted that if the function is realized in the form of a software function module and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the methods described in the embodiments of the present application. The foregoing storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk, and various program codes that can be stored in the medium.

[0101] In this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0102] The above description is merely illustrative of the application and not in limitation of the principles of the application. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the application as defined in the following claims.

Claims

1. A method for fabricating a phase-change photonic device, characterized by, The preparation method comprises the following steps for any phase-change photonic device: preparing a ridge silicon waveguide; preparing a phase-change material layer on the surface of the ridge silicon waveguide to obtain an initial phase-change photonic device; wherein the phase-change material layer covers the ridge silicon waveguide; sequentially irradiating the surface of the initial phase-change photonic device with short pulses of different energy values output by a laser in pulse irradiation stages in sequence according to a stage sequence, so as to gradually reduce the temperature of the phase-change material layer according to the stage sequence and adjust the microstructure of the phase-change material layer in the process of gradually reducing the temperature, change the phase-change photonic synapse weight, and obtain a final phase-change photonic device; wherein the time length corresponding to each pulse irradiation stage is different; for any pulse irradiation stage, the step of sequentially irradiating the surface of the initial phase-change photonic device with short pulses of different energy values output by a laser in pulse irradiation stages in sequence comprises: in the current pulse irradiation stage, sequentially applying a plurality of short pulses with the same energy to the phase-change material layer from above the initial phase-change photonic device by using the laser according to a first preset time interval; wherein the energy corresponding to each pulse irradiation stage gradually decreases in sequence.

2. The production method according to claim 1, characterized by, According to the stage sequence, the initial pulse irradiation stage is the first pulse irradiation stage, and the step of sequentially irradiating the surface of the initial phase-change photonic device with short pulses of different energy values output by a laser in pulse irradiation stages in sequence comprises: in the first pulse irradiation stage, heating the phase-change material layer by outputting a first pulse section by using the laser, so as to melt the phase-change material in the phase-change material layer; wherein the first pulse section at least comprises one short pulse with the same energy value; in the remaining pulse irradiation stages except the first pulse irradiation stage, heating the phase-change material layer by outputting a corresponding pulse section by using the laser, so as to adjust the temperature of the phase-change material to a preset temperature range and make the phase-change material layer in a microstructure switching state; wherein the mean value of the preset temperature range is less than the melting temperature of the phase-change material.

3. The preparation method according to claim 2, characterized in that The mean value of the preset temperature range is equal to 350℃.

4. The method of claim 1, wherein, The first preset time interval is less than or equal to 30 ns.

5. The production method according to any one of claims 1 to 4, characterized by, When the first pulse irradiation stage, the second pulse irradiation stage, and the third pulse irradiation stage are sequentially included in the time sequence, the pulse energies corresponding to the first pulse irradiation stage, the second pulse irradiation stage, and the third pulse irradiation stage are the first pulse energy, the second pulse energy, and the third pulse energy in sequence; and the time intervals corresponding to the first pulse irradiation stage, the second pulse irradiation stage, and the third pulse irradiation stage are the first time interval, the second time interval, and the third time interval in sequence; the step of sequentially irradiating the surface of the initial phase-change photonic device with short pulses of different energy values output by a laser in pulse irradiation stages in sequence comprises: in the first pulse irradiation stage, continuously outputting a short pulse corresponding to a first pulse energy value in a first preset time interval by using the laser, and irradiating the phase-change material layer; In the second pulse irradiation stage, the phase change material layer is irradiated by the laser outputting short pulses corresponding to a plurality of second pulse energy values in a second preset time interval in sequence; In the third pulse irradiation stage, the phase change material layer is irradiated by the laser outputting short pulses corresponding to a plurality of third pulse energies in a third preset time interval in sequence; Wherein, the second pulse energy value is less than the first pulse energy value and greater than the third pulse energy value.

6. The production method according to claim 5, wherein The end time of the first pulse irradiation stage is the same as the start time of the second pulse irradiation stage; the second pulse irradiation stage and the third pulse irradiation stage have a second preset time interval.

7. The production method according to claim 6, characterized by, The second preset time interval is 20 ns.

8. The preparation method according to claim 1, characterized in that, The length of the phase change material layer along the direction of the ridge waveguide is 4 μm, and the thickness is 30 nm.

9. A phase change photonic device, characterized in that, The phase change photonic device is prepared by the preparation method of any one of claims 1 to 8.

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