Sensing, storage and computing integrated structure based on phase change materials

Abstract

The present invention provides a sensing, storage and computing integrated structure based on phase change material, which includes: a visible light filter structure for absorbing or reflecting visible light; a narrow-band absorber cavity structure, located below the visible light filter structure, including a metal layer, a dielectric layer and a phase change layer; a lithium tantalate single crystal structure, located below the narrow-band absorber cavity structure; when light passes through the visible light filter structure and shines on the narrow-band absorber cavity structure, if the phase change material used in the phase change layer is in an amorphous state, the narrow-band absorber cavity structure absorbs the light in a narrow band, and the lithium tantalate single crystal structure generates a first current according to the pyroelectric effect; if the phase change material is in a crystalline state, the narrow-band absorber cavity structure reflects the light, and the lithium tantalate single crystal structure generates a second current according to the pyroelectric effect. The present invention has a dynamically adjustable ratio of target light absorption, fast processing speed, high frame rate, low power consumption, very narrow half-height width, insensitive to angles, simple structure and easy integration.

Description

Technical Field

[0001] The present invention relates to the technical field of phase change materials, and in particular to a sensing, storage and computing integrated structure based on phase change materials. Background Art

[0002] The functional layer materials in the existing integrated sensing, storage and computing structures are mainly made of various types of two-dimensional materials or other types of doped photodiode materials, which are integrated with transistors to form a sensing, storage and computing unit. On the one hand, the functional layer materials of this type of structure are difficult to be compatible with CMOS (Complementary Metal Oxide Semiconductor) processes or difficult to mass produce; on the other hand, in the structure containing transistors, each unit requires a large number of electrodes to operate, which brings challenges to both unit application and system design. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides an integrated sensing, storage and computing structure based on phase change materials.

[0004] The present invention provides a sensing, storage and computing integrated structure based on phase change materials, comprising:

[0005] A visible light filtering structure for absorbing or reflecting visible light;

[0006] A narrow-band absorber cavity structure, located below the visible light filter structure, wherein the narrow-band absorber cavity structure comprises a metal layer, a dielectric layer and a phase change layer;

[0007] A lithium tantalate single crystal structure, located below the narrow-band absorber cavity structure, and the lithium tantalate single crystal structure is used to output current;

[0008] When light passes through the visible light filter structure and shines on the narrow-band absorber cavity structure, if the phase change material used in the phase change layer is in an amorphous state, the narrow-band absorber cavity structure absorbs the light in a narrow band, and the lithium tantalate single crystal structure generates a first current according to the pyroelectric effect; if the phase change material is in a crystalline state, the narrow-band absorber cavity structure reflects the light, and the lithium tantalate single crystal structure generates a second current according to the pyroelectric effect, and the first current is greater than the second current;

[0009] When the state of the phase change material used in the phase change layer of the narrow-band absorber structure is constant, the magnitude of the current output by the lithium tantalate single crystal structure is determined by the intensity of the input light, thereby realizing sensing;

[0010] Due to the non-volatile property, the phase change material can store computing information after electrical operation or annealing at a certain temperature, thereby achieving storage;

[0011] The overall current output of the integrated sensing, storage and computing structure unit is affected by the state of the phase-change material film and the intensity of the input light. The output current can be regarded as the result of the calculation of the light intensity and the information stored in the phase-change material, thereby realizing the calculation. In this way, the unit can complete the integration of sensing, storage and computing.

[0012] According to a sensing, storage and computing integrated structure based on phase change material provided by the present invention, the phase change material transforms between the amorphous state and the crystalline state under electrical operation, changes the state of the narrow-band absorber cavity structure, and further changes the output current of the lithium tantalate single crystal structure.

[0013] According to a sensing, storage and computing integrated structure based on a phase change material provided by the present invention, the refractive index of the phase change material is greater than a first preset threshold value, and the optical loss is greater than a second preset threshold value;

[0014] The reflectivity of the metal layer is greater than a third preset threshold.

[0015] According to a sensing, storage and computing integrated structure based on phase change material provided by the present invention, the metal layer has multiple layers, the dielectric layer has multiple layers, the metal layer is located on both sides of the phase change layer, and the dielectric layer is located on both sides of the phase change layer.

[0016] According to a sensing, storage and computing integrated structure based on phase change material provided by the present invention, the narrow-band absorber cavity structure includes a first dielectric layer, a first metal layer, a second dielectric layer, a phase change layer, a third dielectric layer and a second metal layer arranged in sequence from top to bottom.

[0017] According to a sensing, storage and computing integrated structure based on phase change materials provided by the present invention, the first dielectric layer is a low-K value dielectric material such as MgF2, ZnS, TIO2, the first metal layer is a metal with a higher N value such as Ag, AL, etc., as a reflective layer, the second dielectric layer is a dielectric material with a lower K value such as TIO2, Ta2O5, the phase change material used in the phase change layer is AgInSbTe, InSbTe and other phase change materials, except for low-loss phase change materials, i.e. phase change materials with very low K values, the third dielectric layer is a dielectric material with a lower K value such as TIO2, Ta2O5, and the second metal layer is a metal with a higher N value such as Ag, AL, etc.

[0018] According to an integrated sensing, storage and computing structure based on phase change material provided by the present invention, the thickness of the first dielectric layer is 22nm, the thickness of the first metal layer is 10nm, the thickness of the second dielectric layer is 78nm, the thickness of the phase change material used in the phase change layer is 68nm, the thickness of the third dielectric layer is 78nm, and the thickness of the second metal layer is 200nm. The thickness of each layer is not limited to this, as long as the absorption and adjustment of light in the same wavelength band can be achieved, the thickness of the lithium tantalate single crystal structure is not limited to 75 microns.

[0019] According to a sensing, storage and computing integrated structure based on phase change material provided by the present invention, the thickness of the phase change material is less than 1 micron.

[0020] According to a sensing, storage and computing integrated structure based on phase change material provided by the present invention, there are multiple phase change layers, and each phase change layer includes a phase change material layer and electrode layers located on both sides of the phase change material layer.

[0021] According to a sensing, storage and computing integrated structure based on phase change material provided by the present invention, the electrode layer between two adjacent phase change material layers is shared.

[0022] The sensing, storage and computing integrated structure based on phase change materials provided by the present invention realizes the sensing, storage and computing integrated structure based on phase change materials by sequentially arranging a visible light filtering structure, a narrow-band absorber cavity structure and a lithium tantalate single crystal structure from top to bottom. The ratio of the narrow-band absorber cavity structure to the absorption of target light can be dynamically adjusted through the phase change layer and the lithium tantalate single crystal. The processing speed is fast, the frame rate is high, the power consumption is low, the half-width is very narrow, it is insensitive to angles, the structure is simple and it is easy to integrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a schematic diagram of the sensing, storage and computing integrated structure based on phase change materials provided by the present invention;

[0025] Figure 2 It is a schematic diagram of the computing array structure in the sensing, storage and computing integrated structure based on phase change materials provided by the present invention;

[0026] Figure 3 It is a schematic diagram of the operation process of the integrated sensing, storage and computing structure based on phase change materials provided by the present invention.

[0027] Reference numerals:

[0028] 101: first dielectric layer; 102: first metal layer; 103: second dielectric layer; 104: phase change layer; 105: third dielectric layer; 106: second metal layer; 107: lithium tantalate single crystal structure; 108: visible light filter structure; 201 to 209: operation units in the operation array. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Combine the following Figure 1 The present invention describes a sensing, storage and computing integrated structure based on phase change materials, comprising:

[0031] A visible light filter structure 108, used to absorb or reflect visible light;

[0032] A narrowband absorber cavity structure, located below the visible light filter structure, wherein the narrowband absorber cavity structure comprises a metal layer, a dielectric layer and a phase change layer 104;

[0033] A lithium tantalate single crystal structure 107, located below the narrow-band absorber cavity structure, and the lithium tantalate single crystal structure is used to output current;

[0034] When light passes through the visible light filter structure 108 and shines on the narrow-band absorber cavity structure, if the phase change material used in the phase change layer 104 is in an amorphous state, the narrow-band absorber cavity structure absorbs the light in a narrow band, and the lithium tantalate single crystal structure 107 generates a first current according to the pyroelectric effect; if the phase change material is in a crystalline state, the narrow-band absorber cavity structure reflects the light, and the lithium tantalate single crystal structure 107 generates a second current according to the pyroelectric effect, and the first current is greater than the second current;

[0035] The state of the narrowband absorber cavity structure stores computing information. During the photosensitivity process, the narrowband absorber cavity structure and the lithium tantalate single crystal structure 107 work together so that the current output by the lithium tantalate single crystal structure 107 is the computing result of the information carried by the light and the computing information.

[0036] The integrated sensing, storage and computing structure based on phase change materials includes a visible light filter structure 108, a narrow-band absorber cavity structure and a lithium tantalate single crystal structure 107 which are arranged in sequence from top to bottom.

[0037] When light is irradiated to the visible light filter structure 108, part of the visible light is absorbed or reflected, and the rest of the light passes through, thereby preventing the visible light from affecting the output current. When the light further irradiates the narrow-band absorber cavity structure, the corresponding wavelength is absorbed, and due to the pyroelectric effect, the lithium tantalate single crystal structure 107 can generate current.

[0038] When the phase change material used in the phase change layer 104 is in an amorphous state, the first current generated by the lithium tantalate single crystal structure 107 is a high current; when the phase change material used in the phase change layer 104 is in a crystalline state, the second current generated by the lithium tantalate single crystal structure 107 is a low current.

[0039] An integrated sensing, storage and computing structure unit based on phase change materials can perform sensing through the lithium tantalate film of the lithium tantalate single crystal structure 107, while the phase change material film of the phase change layer 104 stores computing information. Finally, the sensing, storage and computing functions of the entire unit are realized through the coordinated action of the two film materials.

[0040] The current output by the lithium tantalate single crystal structure 107 can be used as a reference to regulate the phase change material of the phase change layer 104, thereby realizing a dynamically adjustable, angle-insensitive, and constantly monitored absorption structure, and finally realizing sensing, storage, and computing in one. This technical strategy overcomes the inherent limitations of existing structures, has a simple device structure, and the materials used can be mass-produced, which has a significant technological advancement significance and opens up new possibilities for the further development of phase change display technology.

[0041] This embodiment realizes an integrated sensing, storage and computing structure based on phase change materials by arranging a visible light filter structure, a narrow-band absorber cavity structure and a lithium tantalate single crystal structure in sequence from top to bottom. The phase change layer and the lithium tantalate single crystal can make the absorption ratio of the narrow-band absorber cavity structure to the target light dynamically adjustable, with fast processing speed, high frame rate, low power consumption, very narrow half-width, insensitive to angles, simple structure and easy integration.

[0042] On the basis of the above embodiments, the phase change material in this embodiment transforms between the amorphous state and the crystalline state under electrical operation, changes the state of the narrowband absorber cavity structure, and further changes the output current of the lithium tantalate single crystal structure 107.

[0043] Below the narrowband absorber cavity structure is a lithium tantalate single crystal structure 107. The selectively absorbed light energy will be converted into heat energy and transmitted to the pyroelectric material. The pyroelectric material converts the heat energy into electrical energy through the pyroelectric effect. Therefore, the voltage applied to the metal driving the phase change material can be regulated according to the output current of the lithium tantalate single crystal structure 107 to control the crystallization and amorphization ratio of the phase change material to regulate the absorption of light.

[0044] The narrow-band absorber cavity structure in this embodiment is adjustable according to actual needs, and the proportion of target light absorption is adjusted to adjust the output current of the unit.

[0045] Based on the above embodiment, in this embodiment, the refractive index of the phase change material is greater than the first preset threshold, and the optical loss is greater than the second preset threshold;

[0046] The reflectivity of the metal layer is greater than a third preset threshold.

[0047] The phase change material used in the phase change layer 104 in the narrowband absorber cavity structure is an ultra-thin phase change material with high refractive index and high optical loss. The metal layer in the narrowband absorber cavity structure uses a metal with high reflectivity.

[0048] An ultra-thin phase change material film with strong optical loss is deposited on a high-reflectivity metal substrate, and a lithium tantalate single crystal wafer is bonded to the bottom of the structure to form an integrated sensing, storage and computing structure based on phase change materials.

[0049] The phase change materials in the narrowband absorber cavity structure may include the following chalcogenides and their alloys, including but not limited to GST, GSST, IST, GeSbTe, AgInSbTe, InSbTe, AgSbTe, Ag2In4Sb 76 Te 17 (AIST) and other high-loss characteristic phase change materials. In addition, the atomic percentages in the above chemical formulas can be varied. The phase change material can further include at least one dopant, such as C, N.

[0050] Preferably, the phase change material is AgInSbTe, which has large loss and large refractive index in the visible light range. The metal layer can use Ag, which is a metal with high reflectivity.

[0051] On the basis of the above embodiments, in this embodiment, the metal layer has multiple layers, the dielectric layer has multiple layers, the metal layer is located on both sides of the phase change layer, and the dielectric layer is located on both sides of the phase change layer.

[0052] The narrowband absorber cavity structure is composed of a metal and a dielectric sandwiching a phase change material to form an FP (Fabry-Perot Cavity) cavity structure. The FP cavity includes a phase change material and metal layers on both sides thereof. The metal layers not only play the role of forming an FP cavity with the phase change material, but also play the role of controlling the phase change of the phase change material. By applying voltage through the electrode layer, the crystal structure of the phase change material can be changed, thereby adjusting the size of the absorption peak of the narrowband absorber structure.

[0053] Based on the above embodiments, Figure 1As shown, the narrowband absorber cavity structure in this embodiment includes a first dielectric layer 101, a first metal layer 102, a second dielectric layer 103, a phase change layer 104, a third dielectric layer 105 and a second metal layer 106 arranged in sequence from top to bottom.

[0054] The narrowband absorber cavity structure consists of a dielectric-metal-dielectric-phase change material-dielectric-metal (MDM) cavity or multiple cavities of the same type.

[0055] The phase change material of the phase change layer 104 can be converted between the crystalline state and the amorphous state under electrical stimulation or laser stimulation, thereby changing the transmittance and reflectivity of the phase change layer 104. A transparent lossless material MgF2 is deposited on the top first dielectric layer 101, and the phase change layer 104 can control the crystallization state of the phase change material by applying a voltage on the second metal layer 106Ag.

[0056] Specifically, a pulse voltage of medium intensity is applied to the second metal layer 106Ag, Ag will generate heat, and the temperature of the phase change material will rise to a temperature range above the crystallization temperature and below the melting temperature under the action of heat, and will be maintained for a certain period of time. At this time, the lattice is orderly arranged to form a crystalline state, realizing the transformation from amorphous state to crystalline state.

[0057] A short and strong voltage is applied to the second metal layer 106Ag, which generates high heat in an instant, causing the temperature of the phase change material to rise above the melting temperature, destroying the long-range order of the crystalline state. The pulse falling edge is very short, causing the phase change material to be quickly cooled to below the crystallization temperature, so that the phase change material is fixed in the amorphous state, and the transition from the crystalline state to the amorphous state is achieved. The ratio of light absorption by the narrow-band absorber cavity structure is regulated by the changes in the transmittance and reflectivity of the phase change material of the phase change layer 104 when it transforms between the amorphous state and the crystalline state.

[0058] The phase change layer 104 of the phase change narrow-band absorption cavity structure has very different absorption of light in different states. The phase change material is stable in the crystalline and amorphous states, so the voltage or laser can be removed when the phase change material is in a stable state. Therefore, the power consumption of the integrated sensing, storage and computing structure during use is very low and is dynamically adjustable.

[0059] Based on the above embodiment, in this embodiment, the first dielectric layer 101 is MgF2, the first metal layer 102 is Ag, the second dielectric layer 103 is TIO2, the phase change material used in the phase change layer 104 is AgInSbTe, the third dielectric layer 105 is TIO2, and the second metal layer 106 is Ag.

[0060] On the basis of the above embodiment, in this embodiment, the thickness of the first dielectric layer 101 is 22nm, the thickness of the first metal layer 102 is 10nm, the thickness of the second dielectric layer 103 is 78nm, the thickness of the phase change material used in the phase change layer 104 is 68nm, the thickness of the third dielectric layer 105 is 78nm, the thickness of the second metal layer 106 is 200nm, and the thickness of the lithium tantalate single crystal structure 107 is 75 microns.

[0061] By applying different voltages to the second metal layer 106, the phase change material changes from amorphous to partially crystallized to completely crystallized. When light passes through the visible light filter structure 108 and irradiates the narrow-band absorber cavity structure, the lithium tantalate single crystal structure 107 outputs a current according to how much light is absorbed by the narrow-band absorber cavity structure. The state of the phase change material is adjusted according to actual needs to control the absorption ratio of the target light.

[0062] Based on the above embodiment, the thickness of the phase change material in this embodiment is less than 1 micron.

[0063] The thickness of the phase change material used in the phase change layer 104 is less than 1 micron. Since the increase in the thickness of the phase change material will increase the temperature required for the crystallization of the phase change material, the more suitable thickness is within 1 micron.

[0064] The phase change material of the phase change layer 104 can be driven by voltage. When driven by voltage, a voltage is applied to the second metal layer 106Ag at the bottom of the narrow-band absorber cavity structure to make the phase change of the phase change material occur.

[0065] On the basis of the above embodiment, in this embodiment, there are a plurality of phase change layers, and each phase change layer includes a phase change material layer and electrode layers located on both sides of the phase change material layer.

[0066] On the basis of the above embodiment, in this embodiment, the electrode layer between two adjacent phase change material layers is shared.

[0067] Figure 2 is a simple schematic diagram of the operation array, where 201 to 209 are operation units in the operation array. Each operation unit corresponds to Figure 1 The integrated sensing, storage and computing structure based on phase change materials.

[0068] Figure 3 for Figure 2The computing process of the computing array in the computing array. When light is irradiated onto the surface of the chip, the light information contained in its light intensity will be transmitted to the units on the surface of the computing array. The visible light filter structure on the device unit filters the input light; the narrowband absorption structure absorbs a certain proportion of the input light and converts it into heat. The amount of heat is affected by the state of the phase change film and the intensity of the input light; the lithium tantalate film converts the heat generated by the narrowband absorption structure into current based on the pyroelectric effect. The narrowband absorption cavity structure of the computing units at different positions inside the computing array stores different information required for computing. The changes in the intensity of the input light at different positions on the array surface interact with the phase change film state of the computing unit at its corresponding position, and are finally converted into output current, thereby completing the function of the sensing storage computing device.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sensing, storage and computing integrated structure based on phase change materials, characterized in that: include: A visible light filtering structure for absorbing or reflecting visible light; A narrow-band absorber cavity structure, located below the visible light filter structure, wherein the narrow-band absorber cavity structure comprises a metal layer, a dielectric layer and a phase change layer; A lithium tantalate single crystal structure, located below the narrow-band absorber cavity structure, and the lithium tantalate single crystal structure is used to output current; When light passes through the visible light filter structure and shines on the narrow-band absorber cavity structure, if the phase change material used in the phase change layer is in an amorphous state, the narrow-band absorber cavity structure absorbs the light in a narrow band, and the lithium tantalate single crystal structure generates a first current according to the pyroelectric effect; if the phase change material is in a crystalline state, the narrow-band absorber cavity structure reflects the light, and the lithium tantalate single crystal structure generates a second current according to the pyroelectric effect, and the first current is greater than the second current; When the state of the phase change material used in the phase change layer of the narrow-band absorber structure is constant, the magnitude of the current output by the lithium tantalate single crystal structure is determined by the intensity of the input light, thereby realizing sensing; Due to the non-volatile property, the phase change material can store computing information after electrical operation or annealing at a certain temperature, thereby achieving storage; The current output of the integrated sensing, storage and computing structure unit is affected by the state of the phase change material film and the input light intensity. The output current can be regarded as the result of the calculation of the light intensity and the information stored in the phase change material, thereby realizing the calculation. In this way, the unit can complete the integration of sensing, storage and computing. The metal layer has multiple layers, the dielectric layer has multiple layers, the metal layer is located on both sides of the phase change layer, and the dielectric layer is located on both sides of the phase change layer.

2. The sensing, storage and computing integrated structure based on phase change material according to claim 1 is characterized in that: Under electrical operation, the phase change material transforms between the amorphous state and the crystalline state, changes the state of the narrow-band absorber cavity structure, and further changes the magnitude of the output current of the lithium tantalate single crystal structure.

3. The sensing, storage and computing integrated structure based on phase change material according to claim 1 is characterized in that: The refractive index of the phase change material is greater than a first preset threshold, and the optical loss is greater than a second preset threshold; The reflectivity of the metal layer is greater than a third preset threshold.

4. The sensing, storage and computing integrated structure based on phase change material according to claim 1 is characterized in that: The narrow-band absorber cavity structure comprises a first dielectric layer, a first metal layer, a second dielectric layer, a phase change layer, a third dielectric layer and a second metal layer which are arranged in sequence from top to bottom.

5. The sensing, storage and computing integrated structure based on phase change material according to claim 4 is characterized in that: The first dielectric layer is a dielectric material of MgF2, ZnS and TIO2 whose K value is less than the fourth preset threshold, the first metal layer is a metal of Ag and AL whose N value is greater than the fifth preset threshold, serving as a reflective layer, the second dielectric layer is a dielectric material of TIO2 and Ta2O5 whose K value is less than the sixth preset threshold, the phase change material used in the phase change layer is a phase change material of AgInSbTe and InSbTe, except for the phase change material whose K value is less than the seventh preset threshold, the third dielectric layer is a dielectric material of TIO2 and Ta2O5 whose K value is less than the eighth preset threshold, and the second metal layer is a metal of Ag and AL whose N value is greater than the ninth preset threshold.

6. The sensing, storage and computing integrated structure based on phase change material according to claim 5 is characterized in that: The thickness of the first dielectric layer is 22nm, the thickness of the first metal layer is 10nm, the thickness of the second dielectric layer is 78nm, the thickness of the phase change material used in the phase change layer is 68nm, the thickness of the third dielectric layer is 78nm, the thickness of the second metal layer is 200nm, and the thickness of the lithium tantalate single crystal structure is 75 microns.

7. The sensing, storage and computing integrated structure based on phase change material according to claim 1 is characterized in that: The thickness of the phase change material is less than 1 micron.

8. The sensing, storage and computing integrated structure based on phase change material according to claim 1 is characterized in that: There are a plurality of phase change layers, and each phase change layer comprises a phase change material layer and electrode layers located on both sides of the phase change material layer.

9. The sensing, storage and computing integrated structure based on phase change material according to claim 8 is characterized in that: The electrode layer between two adjacent phase change material layers is shared.

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