A pyroelectric detector structure based on phase change material

Abstract

The present invention provides a pyroelectric detector structure based on phase change material, including: a narrowband absorber cavity structure, including a metal layer, a dielectric layer and a phase change material layer; a pyroelectric detector, located under the narrowband absorber cavity structure, the pyroelectric detector includes a lithium tantalate single crystal; when light hits the narrowband absorber cavity structure, the narrowband absorber cavity structure is used to absorb light of corresponding wavelength to generate a pyroelectric effect, and the lithium tantalate single crystal is used to generate current to obtain light intensity information of the light according to the magnitude of the current, and change the state of the phase change material layer according to the magnitude of the current to adjust the absorption peak position of the narrowband absorber cavity structure for detection. The present invention has a simple structure, is insensitive to angle changes, can selectively detect narrowbands, and can adjust the range of selective detection in real time, can provide more accurate quantitative results in the fields of material identification and concentration detection, and a single detector can achieve spectral reproduction within a small range.

Description

Technical Field

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

[0002] In recent years, common gas detectors include electrochemical gas detectors, semiconductor gas detectors, catalytic combustion gas detectors, and optical gas detectors. The four common gas detection methods not only have different application scenarios and detected gases, but also different detector performances.

[0003] Among them, semiconductor gas detectors are low-cost and can meet both industrial and civilian needs, but they have poor stability and are greatly affected by the environment; catalytic combustion gas detectors are accurate and respond quickly, but require sufficient oxygen in the working environment and most organic vapors will reduce the life of the detector; infrared detectors have fast response speed and good stability, high signal-to-noise ratio, long life and high accuracy. However, infrared detectors cannot always adjust the movement of the absorption peak position of the target band, and the narrow band is sensitive to angle changes, the structure is complex, and multiple structures are required to complete the detection of different gases.

[0004] In existing narrow-band pyroelectric detectors, multilayer narrow-band absorption structures mainly adopt metal / dielectric / metal structures, metal and dielectric structures, or metasurfaces composed of dielectric / metal, in which the structures are complex and sensitive to angle changes. Most metal / dielectric / metal structures are easily affected by the structure, that is, their colors change with changes in polarization and incident angle. Or the structure composed of metal and dielectric cannot realize dynamic switching combinations and detect the intensity of light. Therefore, it is of great practical significance to design a narrow-band absorption technology that is both dynamically adjustable. Summary of the invention

[0005] The present invention provides a pyroelectric detector structure based on phase change material, which is used to solve the defects of narrow-band pyroelectric detectors in the prior art, such as complex structure, sensitivity to angle changes, and inability to perform dynamic regulation. The structure is simple, insensitive to angle changes, and can be monitored and regulated in real time.

[0006] The present invention provides a pyroelectric detector structure based on phase change material, comprising:

[0007] A narrowband absorber cavity structure, comprising a metal layer, a dielectric layer and a phase change material layer;

[0008] A pyroelectric detector is located below the narrow-band absorber cavity structure, and the pyroelectric detector includes a lithium tantalate single crystal wafer;

[0009] When light hits the narrowband absorption cavity structure, the narrowband absorption cavity structure is used to absorb light of corresponding wavelength to produce a pyroelectric effect. The lithium tantalate single crystal is used to generate current to obtain light intensity information of the light according to the magnitude of the current, and change the state of the phase change material layer according to the magnitude of the current to adjust the absorption peak position of the narrowband absorber cavity structure for detection.

[0010] According to a pyroelectric detector structure based on phase change material provided by the present invention, the narrow-band light absorber cavity structure includes a first metal layer, a first dielectric layer, a phase change material layer, a second dielectric layer, a second metal layer and a third dielectric layer arranged in sequence from bottom to top.

[0011] According to a pyroelectric detector structure based on phase change material provided by the present invention, the voltage applied to the first metal layer is regulated according to the magnitude of the current, and the crystallization and amorphization ratio of the phase change material layer is controlled to regulate the absorption of the light.

[0012] According to a pyroelectric detector structure based on a phase change material provided by the present invention, the optical loss of the phase change material layer is less than a first preset threshold value, and the refractive index is greater than a second preset threshold value;

[0013] The reflectivity of the metal layer is greater than a third preset threshold.

[0014] According to a pyroelectric detector structure based on a phase change material provided by the present invention, the thickness of the phase change material layer is less than 1 micron.

[0015] According to a pyroelectric detector structure based on phase change material provided by the present invention, a reflective layer is further included between the first metal layer and the first dielectric layer;

[0016] The first metal layer is a metal such as W or Ti, the reflective layer is a metal with a high reflectivity such as Ag or AL, and the first dielectric layer is TiO 2 , Ta2O5 or TiN and other transparent dielectric materials, the phase change material layer is SB 2 SE 3 , SbS and other alloys, wherein the percentage of each atom is adjustable, and the phase change material has the characteristics of high N value and low K value, and the second dielectric layer is TIO 2 , Ta2O5 or TiN and other transparent dielectric materials, the second metal layer is Ag, and the third dielectric layer is MgF 2 Or dielectric materials with a K value less than 1 such as ZnS.

[0017] According to a pyroelectric detector structure based on phase change material provided by the present invention, the thickness of the first metal layer is greater than 20nm, the thickness of the reflective layer is 50nm, the thickness of the first dielectric layer is greater than 2nm and less than 2 microns, the thickness of the phase change material layer is greater than 2nm and less than 1 micron, the thickness of the second dielectric layer is greater than 2nm and less than 2 microns, the thickness of the second metal layer is greater than 5nm and less than 50nm, and the thickness of the third dielectric layer is greater than 10nm.

[0018] According to a pyroelectric detector structure based on phase change material provided by the present invention, the pyroelectric detector further includes:

[0019] A pyroelectric upper electrode is located on the lithium tantalate single crystal wafer;

[0020] A pyroelectric lower electrode, located below the lithium tantalate single crystal wafer;

[0021] A lead layer, located below the pyroelectric lower electrode, the lead layer is used to lead out the pyroelectric lower electrode and serve as a lead pad;

[0022] Conductive glue, located between the pyroelectric lower electrode and the lead layer, and used to connect the pyroelectric lower electrode and the lead pad;

[0023] The wet etching isolation layer is located below the lead layer and is used for wet etching isolation to protect the front metal.

[0024] According to a pyroelectric detector structure based on phase change material provided by the present invention, the wet etching isolation layer is silicon nitride or silicon oxide, the lead layer is gold, aluminum or alloy, the pyroelectric lower electrode is a conductive material such as gold, aluminum, platinum or copper, and the pyroelectric upper electrode is gold, aluminum or alloy.

[0025] According to a pyroelectric detector structure based on phase change material provided by the present invention, the thickness of the wet etching isolation layer is greater than 100um, the thickness of the lead layer is 300nm to 2000nm, the thickness of the conductive glue is 5 to 100um, the thickness of the pyroelectric lower electrode is 50 to 300nm, and the thickness of the lithium tantalate single crystal chip is 20 to 100um.

[0026] The present invention provides a pyroelectric detector structure based on phase change material. By combining a narrow-band absorption cavity structure with a pyroelectric detector based on a lithium tantalate single crystal chip, a narrow-band dynamically adjustable pyroelectric detector is formed. The lithium tantalate single crystal chip can generate a current value, and the intensity of the target light is judged according to the magnitude of the current value, and can be used to detect the intensity of the optical signal. While selectively detecting a narrow band, the range of the selective detection can be adjusted in real time. The half-width is very narrow and is insensitive to angles. More accurate quantitative results can be provided in the fields of material identification and concentration detection. A single detector can achieve spectral reproduction within a small range, which provides a way of constructing a miniaturized spectrometer. The structure is simple, easy to integrate, and the switching ratio is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 It is a schematic diagram of the structure of a pyroelectric detector based on phase change material provided by the present invention;

[0029] Figure 2 It is a schematic structural diagram of a narrow-band absorber cavity structure in a pyroelectric detector structure based on a phase change material provided by the present invention;

[0030] Figure 3 It is a schematic structural diagram of a pyroelectric detector based on a lithium tantalate single crystal wafer in a pyroelectric detector structure based on a phase change material provided by the present invention;

[0031] Figure 4 It is a CO2 spectrum curve diagram of a pyroelectric detector structure based on phase change material provided by the present invention;

[0032] Figure 5 It is a schematic diagram of the absorption spectrum of a pyroelectric detector structure based on phase change material provided by the present invention;

[0033] Figure 6 It is a graph showing the angle-insensitive change of the absorption spectrum when the phase-change material is in a crystalline state in a pyroelectric detector structure based on a phase-change material provided by the present invention;

[0034] Figure 7 The present invention provides a pyroelectric detector structure based on phase change material, and shows an absorption spectrum angle-insensitive change diagram when the phase change material is in an amorphous state.

[0035] Reference numerals:

[0036] 101: the first metal layer of the narrowband absorber cavity structure; 102: the reflective layer of the narrowband absorber cavity structure; 103: the first dielectric layer of the narrowband absorber cavity structure; 104: the phase change material layer of the narrowband absorber cavity structure; 105: the second dielectric layer of the narrowband absorber cavity structure; 106: the second metal layer of the narrowband absorber cavity structure; 107: the third dielectric layer of the narrowband absorber cavity structure; 201: the wet etching isolation layer of the pyroelectric detector based on lithium tantalate single crystal; 202: the lead layer of the pyroelectric detector based on lithium tantalate single crystal; 203: the conductive adhesive of the pyroelectric detector based on lithium tantalate single crystal; 204: the pyroelectric lower electrode of the pyroelectric detector based on lithium tantalate single crystal; 205: the lithium tantalate single crystal of the pyroelectric detector based on lithium tantalate single crystal; 206: the pyroelectric upper electrode of the pyroelectric detector based on lithium tantalate single crystal; 301: the wet etching isolation layer of the pyroelectric detector structure based on phase change material The insulating layer is etched by the etching method; 302: the lead layer of the pyroelectric detector structure based on the phase change material; 303: the conductive glue of the pyroelectric detector structure based on the phase change material; 304: the pyroelectric lower electrode of the pyroelectric detector structure based on the phase change material; 305: the lithium tantalate single crystal of the pyroelectric detector structure based on the phase change material; 306: the pyroelectric upper electrode of the pyroelectric detector structure based on the phase change material; 307: the first metal layer of the pyroelectric detector structure based on the phase change material; 308: the reflective layer of the pyroelectric detector structure based on the phase change material; 309: the first dielectric layer of the pyroelectric detector structure based on the phase change material; 310: the phase change material layer of the pyroelectric detector structure based on the phase change material; 311: the second dielectric layer of the pyroelectric detector structure based on the phase change material; 312: the second metal layer of the pyroelectric detector structure based on the phase change material; 313: the third dielectric layer of the narrow-band absorber cavity structure. DETAILED DESCRIPTION

[0037] 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.

[0038] Combine the following Figure 1 The present invention describes a pyroelectric detector structure based on phase change material, comprising:

[0039] A narrowband absorber cavity structure, comprising a metal layer, a dielectric layer and a phase change material layer 310;

[0040] A pyroelectric detector, located below the narrow-band absorber cavity structure, wherein the pyroelectric detector comprises a lithium tantalate single crystal 305;

[0041] When light hits the narrowband absorption cavity structure, the narrowband absorption cavity structure is used to absorb light of corresponding wavelength to produce a pyroelectric effect. The lithium tantalate single crystal 305 is used to generate current to obtain the light intensity information of the light according to the magnitude of the current, and change the state of the phase change material layer according to the magnitude of the current to adjust the absorption peak position of the narrowband absorber cavity structure for detection.

[0042] This embodiment does not limit the number and arrangement order of the metal layer, dielectric layer and phase change material layer 310. Optionally, multiple metal layers are located on both sides of the phase change material layer, and multiple dielectric layers are located on both sides of the phase change material layer to form a FP (Fabry-perot, resonant cavity) cavity structure.

[0043] The metal layers on both sides of the phase change material layer 310 play the role of forming an FP cavity with the phase change material and controlling the phase change of the phase change material. By applying voltage to the metal layers on both sides of the phase change material layer, the crystal structure of the phase change material can be changed, thereby adjusting the absorption peak and position of the narrow-band absorber structure.

[0044] The lithium tantalate single crystal 305 is a pyroelectric material used to generate a pyroelectric effect to convert heat into electricity.

[0045] When the narrowband absorption cavity structure is combined with the lithium tantalate single crystal 305, light is irradiated to the narrowband absorption cavity structure and absorbs the corresponding wavelength. Due to the pyroelectric effect, the lithium tantalate single crystal 305 can generate current, and the light intensity information is obtained according to the current. At the same time, the state of the phase change material can be changed according to the current to achieve the effect of peak movement. The peak movement can be controlled according to actual needs to detect gas and light. Compared with the traditional narrowband absorption structure, this design can monitor the intensity of the target light and realize dynamic switch regulation. It has a simple structure and is easy to integrate.

[0046] Through this design, the narrow-band absorption structure can be adjusted according to actual needs, the peak position of target light absorption can be adjusted, the half-width is very narrow, the absorption rate can reach more than 90%, and the peak position can move up to 300nm. It can also be made insensitive to angles to meet the needs of narrow-band absorbers for absorbers such as gas sensors and monochromatic light detectors.

[0047] The pyroelectric detector structure based on phase change material provided in this embodiment can be used as a miniature spectrometer to test unknown spectra. The refractive index of the phase change material is changed, and the spectral response curve of the detector under different refractive indices is measured using FTIR (Fourier Transform Infrared Spectroscopy). Then a laser is used to calibrate the electrical signal value of the detector under different refractive indices per unit power. For unknown spectra, the electrical signal of the detector under different refractive indices is tested, and the unknown spectrum is inferred through an algorithm. The accuracy of the inferred spectrum is related to the number of refractive index points.

[0048] This embodiment combines a narrow-band absorption cavity structure with a pyroelectric detector based on a lithium tantalate single crystal to form a narrow-band dynamically adjustable pyroelectric detector. The lithium tantalate single crystal can generate a current value, and the intensity of the target light is judged according to the magnitude of the current value, so that it can be used to detect the intensity of the optical signal. While selectively detecting a narrow band, the range of the selective detection can be adjusted in real time. The half-width is very narrow and is insensitive to angles. It can provide more accurate quantitative results in the fields of material identification and concentration detection. A single detector can achieve spectral reproduction within a small range, which provides a way of thinking for building a miniaturized spectrometer. It has a simple structure, is easy to integrate, and has a high switching ratio.

[0049] Based on the above embodiments, Figure 1 As shown, the narrow-band light absorber cavity structure in this embodiment includes a first metal layer 307, a first dielectric layer 309, a phase change material layer 310, a second dielectric layer 311, a second metal layer 312 and a third dielectric layer 313 arranged in sequence from bottom to top.

[0050] The narrowband light absorber cavity structure is composed of a dielectric-metal-dielectric-phase change material-dielectric-metal (MDM) cavity or a plurality of cavities of the same type, wherein the third dielectric layer 313 at the top is a lossless material covering layer.

[0051] On the basis of the above embodiment, in this embodiment, the voltage applied to the first metal layer 307 is regulated according to the magnitude of the current to control the crystallization and amorphization ratio of the phase change material layer 310 so as to regulate the absorption of the light.

[0052] The phase change material of the phase change material layer 310 can be converted between a crystalline state and an amorphous state under electrical stimulation or laser stimulation, thereby causing the transmittance and reflectivity of the phase change material layer 310 to change. A transparent lossless material MgF 2 The phase-change material layer 310 can control the crystallization state of the phase-change material by applying a voltage on the first metal layer 307W.

[0053] Specifically, when a pulse voltage of medium intensity is applied to W, W will generate heat. Under the action of heat, the temperature of the phase change material rises to a temperature range above the crystallization temperature and below the melting temperature, and is 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 to crystalline.

[0054] A short and strong voltage is applied to W, 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, fixing the phase change material in the amorphous state, and realizing the transition from crystalline to amorphous state.

[0055] The ratio of light absorption by the narrow-band absorption cavity structure is regulated by the changes in transmittance and reflectivity of the phase-change material of the phase-change material layer 310 when the phase-change material transforms between the amorphous state and the crystalline state.

[0056] The phase change material of the phase change material layer 310 may include the following sulfide compounds and alloys thereof, including but not limited to: SB 2 SE 3 , SBS and other low-loss and high-refractive-index phase-change materials. In addition, the atomic percentages in the above chemical formulas can be varied. The phase-change material layer can further include at least one dopant, such as C, N. Preferably, the phase-change material is SB 2 SE 3 , which has low loss and high refractive index in the visible light range.

[0057] The phase change layer 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. The power consumption of the entire detection device during the detection process is very low and is dynamically adjustable.

[0058] Based on the above embodiment, in this embodiment, the optical loss of the phase change material layer is less than the first preset threshold, and the refractive index is greater than the second preset threshold;

[0059] The reflectivity of the metal layer is greater than a third preset threshold.

[0060] Schematic diagram of the narrowband absorber cavity structure Figure 2 As shown, it includes a first metal layer 101, a reflective layer 102, a first dielectric layer 103, a phase change material layer 104, a second dielectric layer 105, a second metal layer 106 and a third dielectric layer 107 which are arranged in sequence from bottom to top.

[0061] The phase change material of the narrow band absorber cavity structure can be SB 2 SE 3 , the metal can be Ag. Among them, SB 2SE 3 It is an ultra-thin phase change material with low optical loss, and Ag is a high reflectivity material metal. The phase change material in the narrowband absorber cavity is a low-loss high-refractive index material, including but not limited to SB 2 SE 3 And materials with this property formed by doping.

[0062] The narrowband absorption cavity structure is composed of low-loss and high-refractive-index phase change materials and metal materials. An ultra-thin phase change material film with low optical loss and high refractive index is deposited on a highly reflective metal substrate. There is a lithium tantalate single crystal wafer under the narrowband absorber cavity structure. The selectively absorbed light energy will be converted into heat energy and transmitted to the pyroelectric material. The pyroelectric material converts heat energy into electrical energy through the pyroelectric effect. Therefore, it can be controlled according to the size of the current applied to the metal driving the phase change material, and the crystallization and amorphization ratio of the phase change material can be controlled to control the absorption band of light. Compared with the traditional narrowband absorption structure, this design can monitor the intensity of the target light and realize dynamic switch control. It has a simple structure and is easy to integrate.

[0063] Based on the above embodiment, the thickness of the phase change material layer 310 in this embodiment is less than 1 micrometer.

[0064] The thickness of the phase change material layer 310 is less than 1 micron. As the thickness of the phase change material layer 310 increases, the temperature required for the phase change material to crystallize also increases, so the more suitable thickness is within 1 micron. The phase change material of the phase change material layer 310 can be driven by voltage. When driven by voltage, the metal W at the bottom of the narrow-band absorption cavity structure applies voltage to cause the phase change material to undergo phase change.

[0065] There may be a plurality of phase change material layers 310, each of which includes a phase change material and electrode layers located on both sides of the phase change material. Alternatively, the electrode layers between adjacent phase change material layers may be shared.

[0066] On the basis of the above embodiment, in this embodiment, a reflective layer 308 is further included between the first metal layer 307 and the first dielectric layer 309;

[0067] The first metal layer 307 is a metal such as W or Ti, the reflective layer 308 is a metal with a high reflectivity such as Ag or AL, and the first dielectric layer 309 is TiO 2 , Ta2O5 or TiN and other transparent dielectric materials, the phase change material layer 310 is SB 2 SE 3 , SbS and other alloys, wherein the percentage of each atom is adjustable, and the phase change material has the characteristics of high N value and low K value, and the second dielectric layer 311 is TIO 2, Ta2O5 or TiN and other transparent dielectric materials, the second metal layer 312 is Ag, and the third dielectric layer 313 is MgF 2 Or dielectric materials with a K value less than 1 such as ZnS.

[0068] On the basis of the above embodiments, in this embodiment, the thickness of the first metal layer 307 is greater than 20nm, which can be 200nm, the thickness of the reflective layer 308 is 50nm, the thickness of the first dielectric layer 309 is greater than 2nm and less than 2 microns, which can be 78nm, the thickness of the phase change material layer 310 is greater than 2nm and less than 1 micron, which can be 10nm, the thickness of the second dielectric layer 311 is greater than 2nm and less than 2 microns, which can be 78nm, the thickness of the second metal layer 312 is greater than 5nm and less than 50, which can be 22nm, and the thickness of the third dielectric layer 313 is greater than 10, which can be 22nm.

[0069] By applying different voltages to the first metal layer 307, the phase change material layer 310 changes from amorphous to partially crystallized to completely crystallized. The magnitude of the applied voltage depends on the magnitude of the output current of the lithium tantalate single crystal 305, and the corresponding negative feedback is performed until the detection spectrum effect reaches the target effect, and the absorption ratio of the target light is adjusted according to actual needs.

[0070] Based on the above embodiments, Figure 1 As shown, the pyroelectric detector in this embodiment also includes:

[0071] The pyroelectric upper electrode 306 is located on the lithium tantalate single crystal 305;

[0072] The pyroelectric lower electrode 304 is located below the lithium tantalate single crystal 305;

[0073] A lead layer 302 is located below the pyroelectric lower electrode 304. The lead layer 302 is used to lead out the pyroelectric lower electrode 304 and serve as a lead pad;

[0074] Conductive glue 303, located between the pyroelectric lower electrode 304 and the lead layer 302, the conductive glue 303 is used to connect the pyroelectric lower electrode 304 and the lead pad;

[0075] The wet etching isolation layer 301 is located below the lead layer 302. The wet etching isolation layer 301 is used for wet etching isolation to protect the front metal.

[0076] The structure of the pyroelectric detector based on lithium tantalate single crystal is as follows Figure 3 As shown, from top to bottom, it includes a pyroelectric upper electrode 206, a lithium tantalate single crystal 205, a pyroelectric lower electrode 204, a conductive adhesive 203, a lead layer 202 and a wet-etched isolation layer 201.

[0077] Based on the above embodiments, the wet etching isolation layer in this embodiment is silicon nitride or silicon oxide, the lead layer is gold, aluminum or alloy, the pyroelectric lower electrode is gold, aluminum, platinum or copper and other conductive materials, and the pyroelectric upper electrode is gold, aluminum or alloy and other materials.

[0078] On the basis of the above embodiments, the thickness of the wet etching isolation layer in this embodiment is greater than 100um, and may be 500um, the thickness of the lead layer is 300nm to 2000nm, and may be 1200nm, the thickness of the conductive glue may be 5 to 100, and may be 30um, the thickness of the pyroelectric lower electrode is 50 to 300nm, and may be 100nm, the thickness of the lithium tantalate single crystal chip is 20 to 100um, and may be 75um, and the thickness of the pyroelectric upper electrode is 1200nm.

[0079] Figure 4 This is the spectrum curve of CO2. Figure 5 yes Figure 1 Schematic diagram of the corresponding absorption spectrum.

[0080] Figure 6 yes Figure 1 The corresponding phase change material in the crystalline state has an absorption spectrum with an insensitive angle.

[0081] Figure 7 yes Figure 1 The corresponding absorption spectrum angle-insensitive change diagram when the phase change material is in the amorphous state.

[0082] Compared with traditional thermal detectors, the pyroelectric detector based on phase change material provided in this embodiment is smaller in size and lower in cost, and can be mass-produced through standard semiconductor processes. The absorption structure can be solved. Moreover, the angle dependence is poor. According to the actual application, the thickness of the phase change material layer, the dielectric layer, the metal layer structure and the state of the phase change material layer can be adjusted to achieve the absorption of light in a certain band and change the band of light detection through electrical drive. This can be applied to devices such as photodetectors, and has high practicality and broad application prospects.

[0083] In general, this embodiment adopts a new design concept of a spectrally real-time adjustable pyroelectric detector based on phase change materials, and successfully develops a dynamically adjustable, angle-insensitive, and constantly monitored and regulated absorption structure. This technical strategy overcomes the inherent limitations of existing structures, has significant technological advancement significance, and opens up new possibilities for the further development of phase change display technology.

[0084] 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 pyroelectric detector structure based on phase change material, characterized in that: include: A narrowband absorber cavity structure, comprising a metal layer, a dielectric layer and a phase change material layer; A pyroelectric detector is located below the narrow-band absorber cavity structure, and the pyroelectric detector includes a lithium tantalate single crystal wafer; When light hits the narrowband absorber cavity structure, the narrowband absorber cavity structure is used to absorb light of corresponding wavelength to produce a pyroelectric effect. The lithium tantalate single crystal is used to generate current to obtain light intensity information of the light according to the magnitude of the current, and change the state of the phase change material layer according to the magnitude of the current to adjust the absorption peak position of the narrowband absorber cavity structure for detection.

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

3. The pyroelectric detector structure based on phase change material according to claim 2, characterized in that: The voltage applied to the first metal layer is regulated according to the magnitude of the current, and the ratio of crystallization and amorphization of the phase change material layer is controlled to regulate the absorption of the light.

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

5. The pyroelectric detector structure based on phase change material according to claim 1, characterized in that: The thickness of the phase change material layer is less than 1 micron.

6. The pyroelectric detector structure based on phase change material according to claim 2, characterized in that: A reflective layer is also included between the first metal layer and the first dielectric layer; The first metal layer is metal W or Ti, the reflective layer is metal Ag or Al whose reflectivity is greater than a fourth preset threshold, the first dielectric layer is a transparent dielectric material TiO2, Ta2O5 or TiN, the phase change material layer is one or more of Sb2Se3 and SbS alloys, wherein the percentage of each atom is adjustable, the N value of the phase change material is greater than the fifth preset threshold and the K value is less than the sixth preset threshold, the second dielectric layer is a transparent dielectric material TiO2, Ta2O5 or TiN, the second metal layer is Ag, and the third dielectric layer is a dielectric material MgF2 or ZnS whose K value is less than 1.

7. The pyroelectric detector structure based on phase change material according to claim 6, characterized in that: The thickness of the first metal layer is greater than 20nm, the thickness of the reflective layer is 50nm, the thickness of the first dielectric layer is greater than 2nm and less than 2 microns, the thickness of the phase change material layer is greater than 2nm and less than 1 micron, the thickness of the second dielectric layer is greater than 2nm and less than 2 microns, the thickness of the second metal layer is greater than 5nm and less than 50nm, and the thickness of the third dielectric layer is greater than 10nm.

8. The pyroelectric detector structure based on phase change material according to any one of claims 1 to 7, characterized in that: The pyroelectric detector also includes: A pyroelectric upper electrode is located on the lithium tantalate single crystal wafer; A pyroelectric lower electrode, located below the lithium tantalate single crystal wafer; A lead layer, located below the pyroelectric lower electrode, the lead layer is used to lead out the pyroelectric lower electrode and serve as a lead pad; Conductive glue, located between the pyroelectric lower electrode and the lead layer, and used to connect the pyroelectric lower electrode and the lead pad; The wet etching isolation layer is located below the lead layer and is used for wet etching isolation to protect the front metal.

9. The pyroelectric detector structure based on phase change material according to claim 8, characterized in that: The wet etching isolation layer is made of silicon nitride or silicon oxide, the lead layer is made of gold, aluminum or alloy material, the pyroelectric lower electrode is made of conductive material gold, aluminum, platinum or copper, and the pyroelectric upper electrode is made of gold, aluminum or alloy material.

10. The pyroelectric detector structure based on phase change material according to claim 9, characterized in that: The thickness of the wet etching isolation layer is greater than 100um, the thickness of the lead layer is 300nm to 2000nm, the thickness of the conductive glue is 5 to 100nm, the thickness of the pyroelectric lower electrode is 50 to 300nm, and the thickness of the lithium tantalate single crystal chip is 20 to 100um.

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