Antimony tellurium-based all-optical phase change brain-like calculation device based on novel pulse programming mode
By utilizing the metastable crystal phase of antimony-tellurium alloy and a novel pulse programming method, the antimony-tellurium-based all-optical phase-change neuromorphic computing device solves the problems of small optical performance window and poor programming consistency in the existing technology, thereby expanding the optical window and improving the programming accuracy. It is suitable for fields such as optical signal storage, transmission, sensing systems, high-speed optical interconnection and communication.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XI AN JIAOTONG UNIV
- Filing Date
- 2026-01-21
- Publication Date
- 2026-04-14
AI Technical Summary
Existing germanium-antimony-tellurium phase change materials have insufficient optical performance windows in the optical communication band, resulting in insufficient device switching ratios, a limited number of adjustable logic states, and random nucleation during crystallization, making it difficult to maintain programming consistency and limiting the computational accuracy of phase change neuromorphic computing chips.
An antimony-tellurium-based all-optical phase-change neuromorphic computing device is employed. By utilizing the metastable crystal phase structure of antimony-tellurium alloy and a novel pulse programming method, the phase change material layer is continuously tunable through a combination of uniformly stepped attenuated pulses and isolated rectangular pulses with a variable optical attenuator. This expands the optical contrast window and drives the antimony-tellurium alloy to undergo continuous and controllable phase transitions along the crystal-amorphous interface.
It achieves an improvement of more than 20% in the optical window of the device, a large number of logic states that are continuously adjustable, and a programming precision of more than 7 bits. It improves the consistency of the number and precision of programming logic states of phase-change neuromorphic computing devices, and has a simple structure that is easy to integrate on a large scale.
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Figure CN121865852A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of phase-change optical storage device technology, specifically to an antimony tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method. Background Technology
[0002] Phase change memory (PCM) materials exhibit significant differences in optical properties between their amorphous and crystalline phases, along with nanosecond-level reversible phase transition rates and excellent non-volatility. This provides a physical basis for the dynamic control of photonic devices and enables their widespread application in fields such as neuromorphic computing. All-optical neuromorphic computing devices based on PCM materials program data by adjusting the crystal / amorphous volume ratio of the device using laser pulses. They feature fast write / erase speeds, require no continuous external stimulation, and are continuously adjustable. Furthermore, they are compatible with CMOS processes, facilitating large-scale integration and potentially significantly enhancing computing power, thus contributing to the rapid development of artificial intelligence.
[0003] Currently available commercial phase change materials, germanium-antimony-tellurium (GST-T) are typical nucleation-type phase change materials with crystallization rates reaching several nanoseconds. However, their optical performance window in the optical communication band is not large enough, resulting in a limited on / off ratio and a small number of adjustable logic states. The number of programmable states in a single publicly reported all-optical device is only 65. More importantly, due to the significant randomness of GST-T, the crystallization process cannot occur linearly and continuously, making it difficult to maintain stable programming consistency in neuromorphic computing devices, which greatly limits the computational accuracy of phase change neuromorphic computing chips.
[0004] Therefore, there is an urgent need to develop a novel all-optical phase-change neuromorphic computing device with a large window and high consistency. Summary of the Invention
[0005] To overcome the shortcomings of the existing technology, this invention provides an antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method. By utilizing the reverse optical properties of the metastable crystal phase structure of antimony-tellurium phase-change material and the novel pulse programming method, combined with the optimization of the phase-change region size of the device, the optical contrast window of the phase-change neuromorphic computing device is effectively expanded, realizing the programming of a large number of continuously adjustable logic states (corresponding to the light transmittance in the device).
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method comprises, from bottom to top, a substrate and a waveguide dielectric layer; the waveguide dielectric layer includes a square structure on the bottom surface and a ridge-shaped central protrusion on the bottom surface; a phase change material layer and a protective layer are located above the central protrusion; the phase change material layer is an antimony-tellurium alloy. In the device, uniformly stepped attenuation pulses and isolated rectangular pulses are used to switch the metastable crystalline phase and amorphous phase of the antimony-tellurium alloy; the optical window of the device is increased by more than 20%. By utilizing the growth characteristics of antimony-tellurium alloys, a variable optical attenuator is used to control the power of continuous rectangular laser pulses, driving the antimony-tellurium alloy to undergo a continuous and controllable phase transition along the interface between crystal and amorphous materials. The crystal / amorphous volume ratio of the phase transition material layer can be quantitatively controlled, thereby enabling continuous and adjustable programming of the device's logic state (transmittance).
[0007] The substrate has a length ranging from 1 to 500 mm, a width ranging from 10 to 1000 nm, and a thickness ranging from 1 to 1000 mm. The waveguide dielectric layer includes a square structure on the bottom surface and a protrusion located above the bottom surface; the central protrusion is arranged along the center of the Y-axis on the upper surface of the square structure. The waveguide dielectric layer has a length range of 1-500 mm, the overall width of the bottom square structure ranges of 1-10 mm, the width of the central protrusion ranges of 100-1000 nm, the width of the bottom square structure on both sides of the central protrusion is the same, and the overall width of the bottom surface of the waveguide dielectric layer is the same as the width of the substrate. The thickness of the central protrusion ranges from 10 to 500 nm, and the thickness of the square structure on the bottom surface on both sides of the central protrusion ranges from 10 to 500 nm. The phase change material layer has a length L ranging from 0.5 to 2 μm, a width ranging from 100 to 1000 nm, and a thickness H ranging from 5 to 50 nm. The top protective layer has a length ranging from 0.5 to 2 μm, a width ranging from 100 to 1000 nm, and a thickness ranging from 5 to 100 nm. The width of the upper protrusion is the same as that of the phase change material layer and the top protective layer; The phase change material layer has the same length as the top protective layer, but is shorter than the waveguide dielectric layer.
[0008] The chemical formula of the antimony-tellurium alloy is Sb. x Te 100-x , where 55≤x≤75, x is the atomic percentage, and it has three states: amorphous phase, metastable crystalline phase and stable crystalline phase; In the 1530~1565 nm optical communication band; When antimony-tellurium alloy is in an amorphous phase, it has the lowest refractive index and extinction coefficient, and the highest transmittance of the device. When antimony-tellurium alloys are in a stable crystalline phase, their refractive index and extinction coefficient are moderate, resulting in moderate transmittance of the devices. When antimony-tellurium alloys are in a metastable crystalline phase, they exhibit the highest refractive index and extinction coefficient, while the device transmittance is the lowest. The crystallization process of antimony-tellurium alloys is a growth-type crystallization, exhibiting no significant randomness and maintaining good programming consistency.
[0009] The uniformly stepped decay pulse has an initial level of 2-3 V, a pulse width of 1000-2000 ns, a step decay of 0.2-0.3 V, a step period of 100-200 ns, and a pulse power of 5-20 mW. The uniformly stepped decay pulse can drive the all-optical phase-change neuromorphic computing device to form the largest possible optical window.
[0010] The isolated rectangular pulse has an initial level of 2-3 V, a pulse width of 10-200 ns, and a pulse power range of 5-20 mW.
[0011] The continuous rectangular laser pulses have an initial level of 2-3 V, a pulse width of 10-200 ns, and a pulse power range of 5-20 mW. The power of the continuous rectangular laser pulses is precisely controlled by a variable optical attenuator, with an attenuation power range of 0-20 mW and an adjustment step range of 0.02-0.10 mW. This allows for the continuous and adjustable programming of the logic state (transmittance) of the all-optical phase-change neuromorphic computing device.
[0012] The programming process for the device consists of three steps: First, by applying uniformly stepped decaying pulses, the phase change material layer in the device is made to form a metastable crystalline phase, at which point the device has the lowest transmittance. Subsequently, an isolated rectangular pulse is applied to switch the main region of the phase change material layer in the device to the amorphous phase. At this time, the device has the highest transmittance. This process also creates an interface between the amorphous and metastable crystalline phases. Finally, the power of the continuous rectangular laser pulses is precisely adjusted using a variable optical attenuator to drive the amorphous phase region of the phase change material layer to crystallize quantitatively and gradually along the amorphous / metastable crystal phase interface. This process corresponds to the quantitative programming of the device's logic state (transmittance).
[0013] The waveguide dielectric layer has a thickness ranging from 10 to 300 nm and a width ranging from 10 to 1000 nm; the phase change material layer has a thickness H ranging from 5 to 50 nm and a length L ranging from 0.5 to 2 μm; the top protective layer has a thickness ranging from 5 to 100 nm and a length ranging from 0.5 to 2 μm.
[0014] The substrate is made of either SiO2 or Si, the waveguide dielectric layer is made of either Si or Si3N4, and the top protective layer is made of either SiO2 or ITO.
[0015] The waveguide dielectric layer is ridge-shaped, and the phase change material layer and protective layer are located above the ridge region of the waveguide dielectric layer.
[0016] The preparation methods of the phase change material layer and the top protective layer include, but are not limited to, magnetron sputtering, chemical vapor deposition, atomic layer deposition, and vacuum evaporation.
[0017] The device is used for optical signal storage or transmission, optical sensing systems, high-speed optical interconnects and communications, optical modulators or filters.
[0018] By using the pulse mode provided by this invention to operate on an antimony tellurium-based all-optical phase-change neuromorphic computing device, and further precisely adjusting the energy of continuous rectangular laser pulses through a variable optical attenuator, programming accuracy exceeding 7 bits can be achieved.
[0019] The beneficial effects of this invention are: In this invention, the antimony-tellurium phase change material used as the functional layer has a metastable crystalline phase. The difference in optical constants between the amorphous phase and the metastable crystalline phase of the antimony-tellurium phase change material is greater than the difference in optical constants between the amorphous phase and the stable crystalline phase. By replacing the phase change material layer of the traditional rectangular pulse switching device with a uniform step-attenuation pulse, the transition from the amorphous phase to the metastable crystalline phase can be achieved, the device contrast can be improved by more than 20%, and the large window programming of the device is realized.
[0020] This invention utilizes the growth-type crystallization characteristics of antimony-tellurium alloys, combined with the reverse optical properties of their metastable crystalline phase structure. By precisely adjusting the power of continuous rectangular laser pulses using a variable optical attenuator, the antimony-tellurium alloy can be driven to crystallize and grow along the metastable crystalline / amorphous phase interface. Since the growth process lacks significant nucleation and crystallization randomness, the crystalline / amorphous volume ratio of the phase change material layer can be quantitatively controlled, enabling quantitative programming of the device's logic states (transmittance). Using the pulse method provided by this invention on an antimony-tellurium-based all-optical phase change neuromorphic computing device, a programming accuracy exceeding 7 bits (128 states) can be achieved, far surpassing traditional germanium-antimony-tellurium devices, significantly improving the consistency of the number and accuracy of programming logic states in the phase change neuromorphic computing device.
[0021] Furthermore, this invention features a simple and compact structure, effectively increasing chip integration density. Its fabrication process is compatible with existing CMOS processes, facilitating large-scale integrated production. The all-optical phase-change neuromorphic computing device provided by this invention can also be used for optical signal storage or transmission, optical sensing systems, high-speed optical interconnects and communications, optical modulators or filters, etc. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of an antimony tellurium-based all-optical phase-change neuromorphic computing device.
[0023] Figure 2The refractive index of antimony-tellurium phase change materials in amorphous, metastable, and stable crystalline phases. n Curve showing the change with wavelength.
[0024] Figure 3 The extinction coefficients of antimony-tellurium phase change materials in amorphous, metastable, and stable crystalline phases. k Curve showing the change with wavelength.
[0025] Figure 4 The transmittance windows of the antimony-tellurium phase change material layer in amorphous, metastable, and stable crystalline phases are given.
[0026] Figure 5 This is a uniformly stepped decay pulse waveform.
[0027] Figure 6 It is an isolated rectangular pulse waveform.
[0028] Figure 7 This represents the window for the antimony-tellurium phase change material layer to switch between the amorphous phase and the metastable crystalline phase.
[0029] Figure 8 It is a continuous rectangular laser pulse waveform.
[0030] Figure 9 Programming windows for antimony-tellurium phase change material layers in amorphous and metastable crystalline phases. Detailed Implementation
[0031] The present invention will now be described in further detail with reference to the accompanying drawings.
[0032] like Figure 1 The diagram shows a schematic of an antimony tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method; it includes a substrate 1 and a waveguide dielectric layer 2. The waveguide dielectric layer 2 is ridge-shaped, and both the phase change material layer 3 and the protective layer 4 are rectangular pattern designs. The phase change material layer 3 and the protective layer 4 are located above the central protrusion of the ridge region of the waveguide dielectric layer 2.
[0033] The substrate 1 has a length ranging from 1 to 500 mm, a width ranging from 10 to 1000 nm, and a thickness ranging from 1 to 1000 mm.
[0034] The waveguide dielectric layer 2 has a square structure on the bottom surface and a central protrusion on the top surface; The waveguide dielectric layer 2 has a length ranging from 1 to 500 mm, an overall width of 1 to 10 mm for the bottom square structure, a width of 100 to 1000 nm for the central protrusion, and the same width for the bottom square structure on both sides of the central protrusion. The overall width of the bottom surface of the waveguide dielectric layer 2 is the same as the width of the substrate. The thickness of the central protrusion ranges from 10 to 500 nm, and the thickness of the bottom square structure on both sides of the central protrusion ranges from 10 to 500 nm.
[0035] The phase change material layer 3 has a length L ranging from 0.5 to 2 μm, a width ranging from 100 to 1000 nm, and a thickness H ranging from 5 to 50 nm.
[0036] The top protective layer 4 has a length ranging from 0.5 to 2 μm, a width ranging from 100 to 1000 nm, and a thickness ranging from 5 to 100 nm.
[0037] The chemical formula of the antimony-tellurium alloy is Sb. x Te 100-x , where 55≤x≤75, x is the atomic percentage, and it has three states: amorphous phase, metastable crystalline phase and stable crystalline phase; In the 1530~1565 nm optical communication band; When antimony-tellurium alloy is in an amorphous phase, it has the lowest refractive index and extinction coefficient, and the highest transmittance of the device. When antimony-tellurium alloys are in a stable crystalline phase, their refractive index and extinction coefficient are moderate, resulting in moderate transmittance of the devices. When antimony-tellurium alloys are in a metastable crystalline phase, they exhibit the highest refractive index and extinction coefficient, while the device transmittance is the lowest. The crystallization process of antimony-tellurium alloys is a growth-type crystallization, exhibiting no significant randomness and maintaining good programming consistency.
[0038] The uniformly stepped decay pulse has an initial level of 2-3 V, a pulse width of 1000-2000 ns, a step decay of 0.2-0.3 V, a step period of 100-200 ns, and a pulse power of 5-20 mW. The uniformly stepped decay pulse can drive the all-optical phase-change neuromorphic computing device to form the largest possible optical window.
[0039] The isolated rectangular pulse has an initial level of 2-3 V, a pulse width of 10-200 ns, and a pulse power range of 5-20 mW.
[0040] The continuous rectangular laser pulses have an initial level of 2-3 V, a pulse width of 10-200 ns, and a pulse power range of 5-20 mW. The power of the continuous rectangular laser pulses is precisely controlled by a variable optical attenuator, with an attenuation power range of 0-20 mW and an adjustment step range of 0.02-0.10 mW. This allows for the continuous and adjustable programming of the logic state (transmittance) of the all-optical phase-change neuromorphic computing device.
[0041] The present invention will be further illustrated below with specific embodiments.
[0042] Example 1 This embodiment is based on Sb 70 Te 30 All-optical phase-change neuromorphic computing device.
[0043] Sb 70 Te 30 Phase change materials are prepared by single-target sputtering.
[0044] The Sb-based 70 Te 30 The structure of all-optical phase-change neuromorphic computing devices, such as Figure 1 As shown, the materials selected for each layer of the device are: substrate is SiO2; waveguide dielectric layer is Si; phase change material layer is Sb. 70 Te 30 The top protective layer is ITO. The dimensions of each layer of the device are as follows: substrate length is 200 mm, width is 2 mm, and thickness is 500 mm; waveguide dielectric layer length is 200 mm, center width is 450 nm, center thickness is 220 nm, and thickness on both sides is 70 nm; phase change material layer length is 1 μm, width is 450 nm, and thickness is 10 nm; top protective layer length is 1 μm, width is 450 nm, and thickness is 10 nm.
[0045] The Sb-based 70 Te 30 All-optical phase-change neuromorphic computing devices achieve stable switching between amorphous phase, metastable crystalline phase, and stable crystalline phase by adjusting the waveform and power of the applied laser pulse; The uniformly stepped decay pulse has an initial level of 2V, and then in each step cycle... t s =100 ns level with a fixed attenuation Δ A =0.2 V decreasing step by step. Isolated rectangular pulses with a duration of... t pThe laser maintains a constant level of 2 V for 60 ns, with a pulse power of 10.5 mW. There are 64 consecutive rectangular laser pulses, each with a level of 2 V, a pulse width of 60 ns, and a pulse power adjustable from 0 to 10.5 mW.
[0046] Stable and reversible switching between amorphous and metastable crystalline phases can be achieved using isolated rectangular pulses followed by uniformly stepped attenuating pulses for excitation, with the switching window improved by more than 20% compared to the window between amorphous and stable crystalline phases. By precisely adjusting the power of continuous rectangular laser pulses using a variable optical attenuator, antimony-tellurium alloys can be driven to crystallize and grow along the metastable / amorphous phase interface, achieving 64 consecutive logic states (more than 7 bits) on a single device.
[0047] Example 2 This embodiment is based on Sb 65 Te 35 All-optical phase-change neuromorphic computing devices.
[0048] Sb 65 Te 35 Phase change materials are prepared by single-target sputtering.
[0049] The Sb-based 65 Te 35 The structure of all-optical phase-change neuromorphic computing devices, such as Figure 1 As shown, the materials selected for each layer of the device are: substrate is SiO2; waveguide dielectric layer is Si; phase change material layer is Sb. 70 Te 30 The top protective layer is ITO. The dimensions of each layer of the device are as follows: substrate length is 200 mm, width is 2 mm, and thickness is 500 mm; waveguide dielectric layer length is 200 mm, center width is 450 nm, center thickness is 220 nm, and thickness on both sides is 70 nm; phase change material layer length is 1 μm, width is 450 nm, and thickness is 10 nm; top protective layer length is 1 μm, width is 450 nm, and thickness is 10 nm.
[0050] The Sb-based 65 Te 35 The all-optical phase-change neuromorphic computing device achieves stable switching between amorphous, metastable crystalline, and stable crystalline phases by adjusting the waveform and power of the applied laser pulse. The uniformly stepped decay pulse has an initial level of 2V, and then... t s =100 ns level with a fixed attenuation Δ A =0.2 V decreasing step by step. Isolated rectangular pulses with a duration of... t pThe laser maintains a constant level of 2 V for 60 ns, with a pulse power of 10.5 mW. A total of 158 consecutive rectangular laser pulses are generated, each with a level of 2 V, a pulse width of 60 ns, and a pulse power adjustable from 0 to 10.5 mW.
[0051] Stable and reversible switching between amorphous and metastable crystalline phases can be achieved using isolated rectangular pulses followed by uniformly stepped attenuating pulses for excitation, with the switching window improved by more than 20% compared to the window between amorphous and stable crystalline phases. By precisely adjusting the power of continuous rectangular laser pulses using a variable optical attenuator, antimony-tellurium alloy can be driven to crystallize and grow along the metastable / amorphous phase interface, achieving 158 consecutive logic states (more than 7 bits) on a single device.
[0052] A convolutional neural network for digit or image recognition can be constructed based on the 158 consecutive logic states of this device, achieving a recognition accuracy of approximately 98%.
[0053] like Figure 2 As shown, the refractive index of the antimony-tellurium phase change material in this embodiment 2 is shown in the amorphous phase, metastable crystalline phase, and stable crystalline phase. n The refractive index of the amorphous phase varies with wavelength. Within the wavelength range of 300-790 nm. n The refractive index of the amorphous phase is greater than that of metastable and stable crystalline phases; in the wavelength range of 870-2100 nm, the refractive index of the amorphous phase is... n The refractive index of the metastable crystal phase is smaller than that of the stable crystal phase. The metastable and stable crystal phases show similar refractive index trends in the range of 300-2100 nm, but in the range of 300-1280 nm, the refractive index of the stable crystal phase is higher than that of the metastable crystal phase, and in the range of 1280-2100 nm, the refractive index of the metastable crystal phase is higher than that of the stable crystal phase.
[0054] like Figure 3 The figure shows the extinction coefficients of the antimony-tellurium phase change material in Example 2 under amorphous, metastable, and stable crystalline phases. k The extinction coefficient of the amorphous phase varies with wavelength. Within the wavelength range of 300-330 nm. k The extinction coefficient of the amorphous phase is greater than that of both metastable and stable crystalline phases; in the wavelength range of 340-2100 nm, the extinction coefficient of the amorphous phase is... k The extinction coefficient is smaller than that of metastable and stable crystalline phases. Metastable and stable crystalline phases exhibit similar refractive index trends in the 300-2100 nm range, but the extinction coefficient of the metastable crystalline phase is consistently higher than that of the stable crystalline phase. Extinction coefficient kThe larger the value, the stronger the absorption of optical signals, and the lower the transmittance of the device. The difference in extinction coefficient between the amorphous phase and the metastable crystalline phase of antimony tellurium in the communication band (1530-1565 nm) is significantly greater than the difference in extinction coefficient between the amorphous phase and the stable crystalline phase in the same band.
[0055] like Figure 4 As shown, the transmittance spectra of the antimony-tellurium-based all-optical phase-change neuromorphic computing device in this embodiment 2 are displayed when the phase change material layer is in an amorphous phase, a metastable crystalline phase, and a stable crystalline phase. Transmittance is defined as the ratio of output optical power to input optical power. When the phase change material layer is in an amorphous phase, absorption is low and transmittance is high; when the phase change material layer is in a metastable crystalline phase or a stable crystalline phase, absorption is high and transmittance is low. The transmittance of the amorphous phase, metastable crystalline phase, and stable crystalline phase are 72%, 13%, and 21%, respectively. The transmittance difference window between the amorphous phase and the stable crystalline phase is less than 50%, and the transmittance difference window between the amorphous phase and the metastable crystalline phase is 60%. The transmittance contrast of the reference germanium-antimony-tellurium crystalline phase and the amorphous phase is 40%, and the device window can be improved by more than 20%.
[0056] like Figure 9 As shown, this is the result of stepwise programming between the amorphous phase and metastable crystal phase of the antimony tellurium-based all-optical phase-change neuromorphic computing device in Example 2. By using a variable optical attenuator to precisely adjust the energy of isolated rectangular laser pulses, 158 consecutive logic states, exceeding 7 bits, were obtained on a single device.
[0057] Example 3: This embodiment is based on Sb 55 Te 45 All-optical phase-change neuromorphic computing device.
[0058] Sb 55 Te 45 Phase change materials are prepared by single-target sputtering.
[0059] The substrate is SiO2; the waveguide dielectric layer is Si; and the phase change material layer is Sb. 55 Te 45 The top protective layer is ITO. The dimensions of each layer of the device are as follows: substrate length is 200 mm, width is 2 mm, and thickness is 500 mm; waveguide dielectric layer length is 200 mm, center width is 450 nm, center thickness is 220 nm, and thickness on both sides is 70 nm; phase change material layer length is 1 μm, width is 450 nm, and thickness is 10 nm; top protective layer length is 1 μm, width is 450 nm, and thickness is 10 nm.
[0060] The Sb-based 55 Te 45All-optical phase-change neuromorphic computing devices achieve stable switching between amorphous phase, metastable crystalline phase, and stable crystalline phase by adjusting the waveform and power of the applied laser pulse; The uniformly stepped decay pulse has an initial level of 2V, and then in each step cycle... t s =100 ns level with a fixed attenuation Δ A =0.2 V decreasing step by step. Isolated rectangular pulses with a duration of... t p The laser maintains a constant level of 2 V for 60 ns, with a pulse power of 10.5 mW. A total of 93 consecutive rectangular laser pulses are generated, with a level of 2 V, a pulse width of 60 ns, and a pulse power adjustable from 0 to 10.5 mW.
[0061] Stable and reversible switching between amorphous and metastable crystalline phases can be achieved using isolated rectangular pulses followed by uniformly stepped attenuating pulses for excitation, with the switching window improved by more than 20% compared to the window between amorphous and stable crystalline phases. By precisely adjusting the power of continuous rectangular laser pulses using a variable optical attenuator, antimony-tellurium alloys can be driven to crystallize and grow along the metastable / amorphous phase interface, achieving 93 consecutive logic states on a single device.
[0062] Example 4: This embodiment is based on Sb 75 Te 25 All-optical phase-change neuromorphic computing device.
[0063] Sb 75 Te 25 Phase change materials are prepared by single-target sputtering.
[0064] The substrate is SiO2; the waveguide dielectric layer is Si; and the phase change material layer is Sb. 75 Te 25 The top protective layer is ITO. The dimensions of each layer of the device are as follows: substrate length is 200 mm, width is 2 mm, and thickness is 500 mm; waveguide dielectric layer length is 200 mm, center width is 450 nm, center thickness is 220 nm, and thickness on both sides is 70 nm; phase change material layer length is 1 μm, width is 450 nm, and thickness is 10 nm; top protective layer length is 1 μm, width is 450 nm, and thickness is 10 nm.
[0065] The Sb-based 75 Te 25 All-optical phase-change neuromorphic computing devices achieve stable switching between amorphous phase, metastable crystalline phase, and stable crystalline phase by adjusting the waveform and power of the applied laser pulse; The uniformly stepped decay pulse has an initial level of 2V, and then in each step cycle... t s =100 ns level with a fixed attenuation Δ A =0.2 V decreasing step by step. Isolated rectangular pulses with a duration of... t p The laser maintains a constant level of 2 V for 60 ns, with a pulse power of 10.5 mW. There are 32 consecutive rectangular laser pulses, each with a level of 2 V, a pulse width of 60 ns, and a pulse power adjustable from 0 to 10.5 mW.
[0066] Stable and reversible switching between amorphous and metastable crystalline phases can be achieved using isolated rectangular pulses followed by uniformly stepped attenuating pulses for excitation, with the switching window improved by more than 20% compared to the window between amorphous and stable crystalline phases. By precisely adjusting the power of continuous rectangular laser pulses using a variable optical attenuator, antimony-tellurium alloys can be driven to crystallize and grow along the metastable / amorphous phase interface, achieving 32 consecutive logic states on a single device.
[0067] like Figure 5 As shown, this is a uniformly decaying pulse during the stable transition from an amorphous phase to a metastable crystalline phase. The pulse decreases with equal amplitude and duration, starting from the initial level. A 0, then in each step cycle t s Internal level at a fixed attenuation ΔA Decreasing step by step.
[0068] like Figure 6 As shown, this is an isolated rectangular pulse that stably switches from a metastable crystalline phase to an amorphous phase. The pulse has a duration of [duration missing]. t p Maintain a constant level within the range A Its pulse power is P .
[0069] like Figure 7 As shown, this represents the results of repeated reversible switching between amorphous and metastable crystalline phases in an antimony-tellurium-based all-optical phase-change neuromorphic computing device. Using the stable crystalline phase as the ground state, a lower state can be achieved based on the stable crystalline ground state using uniformly stepped decaying pulses. The antimony-tellurium-based all-optical phase-change neuromorphic computing device can achieve an on / off ratio of nearly 100%, which is more than 20% higher than the stable crystalline-amorphous phase window.
[0070] like Figure 8 As shown, this is a series of rectangular laser pulses, and the number of these pulses is... n Number of pulses n It depends on the number of programs. Utilizing levels. A Pulse width tp and pulse power P1-P n The pulse description is performed. A variable optical attenuator is used to precisely adjust the power of each rectangular pulse. The pulse power monotonically increases from the 1st to the nth pulse, that is, for each pulse number... i (1≤ i ≤ n -1), satisfying P i+1 >P i .
Claims
1. A novel antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method, characterized in that, Along the Z-axis, from bottom to top, are a substrate and a waveguide dielectric layer; the waveguide dielectric layer includes a square structure on the bottom surface and a ridge-shaped central protrusion on the bottom surface; the phase change material layer and the protective layer are located above the central protrusion in sequence; The phase change material layer is an antimony-tellurium alloy; In the device, a uniformly stepped decaying pulse and an isolated rectangular pulse are used to switch the metastable crystalline phase and the amorphous phase of the antimony-tellurium alloy. By utilizing the growth characteristics of antimony-tellurium alloys, a variable optical attenuator is used to control the power of continuous rectangular laser pulses, driving the antimony-tellurium alloy to undergo a continuous and controllable phase transition along the interface between crystal and amorphous materials. The volume ratio of crystal to amorphous materials in the antimony-tellurium alloy can be quantitatively controlled, thereby enabling continuous and adjustable programming of the device's logic state.
2. The antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method according to claim 1, characterized in that, The substrate has a length ranging from 1 to 500 mm, a width ranging from 10 to 1000 nm, and a thickness ranging from 1 to 1000 mm. The central protrusion is located on the upper surface of the square structure along the center of the Y-axis. The waveguide dielectric layer has a length range of 1-500 mm, the overall width of the bottom square structure ranges of 1-10 mm, the width of the central protrusion ranges of 100-1000 nm, the width of the bottom square structure on both sides of the central protrusion is the same, and the overall width of the bottom surface of the waveguide dielectric layer is the same as the width of the substrate. The thickness of the central protrusion ranges from 10 to 500 nm, and the thickness of the square structure on the bottom surface on both sides of the central protrusion ranges from 10 to 500 nm. The phase change material layer has a length L ranging from 0.5 to 2 μm, a width ranging from 100 to 1000 nm, and a thickness H ranging from 5 to 50 nm. The top protective layer has a length ranging from 0.5 to 2 μm, a width ranging from 100 to 1000 nm, and a thickness ranging from 5 to 100 nm. The width of the central protrusion at the top is the same as that of the phase change material layer and the top protective layer; The phase change material layer has the same length as the top protective layer, but is shorter than the waveguide dielectric layer.
3. The antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method according to claim 1, characterized in that, The chemical formula of the antimony-tellurium alloy is Sb. x Te 100-x Where 55≤x≤75, x is the atomic percentage, and antimony-tellurium alloy has three states: amorphous phase, metastable crystalline phase, and stable crystalline phase; In the 1530~1565 nm optical communication band; When antimony-tellurium alloy is in an amorphous phase, it has the lowest refractive index and extinction coefficient, and the highest transmittance of the device. When antimony-tellurium alloys are in a stable crystalline phase, their refractive index and extinction coefficient are moderate, resulting in moderate transmittance of the devices. When antimony-tellurium alloy is a metastable crystalline phase, it has the highest refractive index and extinction coefficient, and the lowest transmittance of the device.
4. The antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method according to claim 1, characterized in that, The uniform step decay pulse has an initial level of 2-3 V, a pulse width of 1000-2000 ns, a step decay amount of 0.2-0.3 V, a step period of 100-200 ns, and a pulse power of 5-20 mW.
5. The antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method according to claim 1, characterized in that, The isolated rectangular pulse has an initial level of 2-3 V, a pulse width of 10-200 ns, and a pulse power range of 5-20 mW.
6. The antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method according to claim 1, characterized in that, The continuous rectangular laser pulses have an initial level of 2-3 V, a pulse width of 10-200 ns, and a pulse power range of 5-20 mW. The power of the continuous rectangular laser pulses is precisely controlled by a variable optical attenuator, with an attenuation power range of 0-20 mW and an adjustment step range of 0.02-0.10 mW. This allows for the continuous and adjustable programming of the logic state of the all-optical phase-change neuromorphic computing device.
7. The antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method according to claim 6, characterized in that, The programming process for the device consists of three steps: First, by applying uniformly stepped decaying pulses, the phase change material layer in the device is made to form a metastable crystalline phase, at which point the device has the lowest transmittance. Subsequently, applying an isolated rectangular pulse causes the main region of the antimony-tellurium alloy material in the phase change material layer of the device to switch to the amorphous phase. At this time, the device has the highest transmittance and an interface between the amorphous and metastable crystalline phases is formed. Finally, by using a variable optical attenuator to precisely adjust the power of continuous rectangular laser pulses, the amorphous phase region of the antimony-tellurium alloy material in the phase change material layer is driven to gradually crystallize along the amorphous / metastable crystal phase interface, which corresponds to the quantitative programming of the device logic state.
8. The antimony-tellurium-based all-optical phase-change neuromorphic computing device based on a novel pulse programming method according to claim 1, characterized in that, The substrate is made of either SiO2 or Si, the waveguide dielectric layer is made of either Si or Si3N4, and the top protective layer is made of either SiO2 or ITO.
9. The application of the antimony-tellurium-based all-optical phase-change neuromorphic computing device prepared by the method according to any one of claims 1-8, characterized in that, The device is used for optical signal storage or transmission, optical sensing systems, high-speed optical interconnects and communications, optical modulators or filters.