Infrared light source structure and method of manufacture and gas sensor and method of measurement

Abstract

This invention provides an infrared light source structure and its fabrication method, as well as a gas sensor and its measurement method. The infrared light source structure includes a substrate, an opening, an insulating layer, a heating and radiating layer, and a metasurface filtering layer. The metasurface filtering layer includes a dielectric layer and a metal layer encased by the dielectric layer. The metal layer includes several first metal units and several second metal units on the same layer. Each first metal unit includes multiple first metal structures arranged in an array and having multiple first through-holes. Each second metal unit includes multiple second metal structures arranged in an array and having multiple second through-holes. The topologies of the first and second metal structures are the same, but their period lengths and the sizes of the first and second through-holes are different. The two narrowband infrared radiations with different wavelengths generated can be directly acquired by an infrared detector without additional processing, thus improving the energy of the infrared radiation.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices, and more particularly to an infrared light source structure and preparation method, and a gas sensor and measurement method. Background Technology

[0002] MEMS infrared light sources are miniature devices used to generate infrared radiation. For example... Figure 1 As shown, the basic structure of a MEMS infrared light source, from bottom to top, consists of a substrate 10 with a cavity, an insulating layer 20, a heating and radiating layer 30, and a protective layer 40. This structure produces a wide range of infrared radiation wavelengths. Although the infrared wavelength range can be adjusted by regulating the temperature of the heating and radiating layer, it is still difficult to achieve infrared light emission in a single band.

[0003] One major application of MEMS infrared light sources is as a light source for gas sensors. Because MEMS infrared light sources produce infrared radiation with a wide wavelength range, they must be used with filters when applied to gas sensors. Please refer to [reference needed]. Figure 2 The gas sensor comprises a gas chamber, a MEMS infrared light source, a filter, and an infrared detector. The MEMS infrared light source is located on one side of the gas chamber, while the filter and infrared detector are located on the other side. The distance between the filter and the MEMS infrared light source is less than the distance between the infrared detector and the MEMS infrared light source. When the gas sensor measures gas concentration, the gas to be measured fills the space between the MEMS infrared light source and the filter. The infrared detector detects the energy of the infrared radiation emitted by the MEMS infrared light source after passing through the gas to be measured and the filter, thereby inferring the concentration of the gas to be measured.

[0004] However, when MEMS infrared light sources are used as gas sensor light sources, the infrared energy after passing through the filter is weak, resulting in low energy utilization and reduced detection accuracy. Furthermore, because the filter cannot be integrated with existing MEMS chip processes and its large size requires additional packaging processes, the cost of the gas sensor is high. Summary of the Invention

[0005] This invention provides an infrared light source structure and preparation method, as well as a gas sensor and measurement method, which improves the energy utilization rate of infrared radiation with a simple structure.

[0006] According to a first aspect of the present invention, an infrared light source structure is provided, comprising: Substrate; An opening is located within the substrate and extends through the substrate; An insulating layer is located on the top surface of the substrate and an opening that exposes the bottom surface of the insulating layer. A heat-radiating layer, at least located on the top surface of an insulating layer above the opening; A metasurface filter layer, located at least above the surface of the heat-radiating layer above the opening, comprises a dielectric layer and a metal layer encapsulated by the dielectric layer. The metal layer comprises a plurality of first metal units and a plurality of second metal units located on the same layer. The first metal units are assembled from a plurality of first metal structures arranged in an array, and the first metal structures have a plurality of first through-holes filled by the dielectric layer. The second metal units are assembled from a plurality of second metal structures arranged in an array, and the second metal structures have a plurality of second through-holes filled by the dielectric layer. The topology of the first metal structures is the same as that of the second metal structures, but the period length of the first metal structures is different from that of the second metal structures, and the size of the first through-holes is different from that of the second through-holes.

[0007] Optionally, the vertical projections of the first metal structure and the second metal structure on the heat-radiating layer have the same shape, and the vertical projections of the first through hole and the second through hole on the heat-radiating layer have the same shape.

[0008] Optionally, the thickness of the metal layer ranges from 100nm to 200nm, and the thickness of the dielectric layer ranges from 500nm to 600nm.

[0009] Optionally, the dielectric layer is made of any one of silicon dioxide, silicon nitride, and silicon oxynitride; the metal layer is made of any one of gold, silver, and copper; the insulating layer is made of silicon oxide or silicon nitride; and the heating and radiating layer is made of any one of doped polycrystalline silicon, tungsten, and platinum.

[0010] Optionally, the first metal unit and the second metal unit in the metal layer are arranged in an array, and the first metal unit and the second metal unit are alternately spliced ​​together.

[0011] Optionally, the plurality of first through holes in the first metal structure are arranged in a rotationally symmetrical manner, and the plurality of second through holes in the second metal structure are arranged in a rotationally symmetrical manner, wherein the center of the first metal structure is the rotation center corresponding to the plurality of first through holes, and the center of the second metal structure is the rotation center corresponding to the plurality of second through holes.

[0012] According to a second aspect of the present invention, a gas sensor is provided, comprising: The aforementioned infrared light source structure is used to emit first infrared radiation with a first center wavelength and second infrared radiation with a second center wavelength, wherein the first center wavelength and the second center wavelength are not equal; A gas chamber is used to contain the gas to be tested; the gas chamber has an incident end and a receiving end, the infrared light source structure is located at the incident end of the gas chamber, and the first infrared radiation and the second infrared radiation are emitted through the receiving end after the gas to be tested absorbs energy in the gas chamber; an infrared detector is located at the receiving end of the gas chamber and is used to acquire the first infrared radiation and the second infrared radiation after the gas to be tested absorbs energy.

[0013] Optionally, the first center wavelength and the second center wavelength satisfy: ,in, The first center wavelength, This is the second center wavelength.

[0014] According to a third aspect of the present invention, a gas concentration measurement method is provided, based on the above-described gas sensor, comprising: Acquire the initial energy information of the first infrared radiation with a first center wavelength and the second infrared radiation with a second center wavelength emitted by the infrared light source structure; The final energy information of the first and second infrared radiations after the gas to be tested has absorbed energy is obtained from the infrared detector. The concentration of the gas to be tested is obtained based on the initial energy information and the final energy information.

[0015] According to a fourth aspect of the present invention, a method for preparing an infrared light source structure is provided, comprising: Provide substrate; An insulating layer is formed on the surface of the substrate; A heat-radiating layer is formed on the surface of the insulating layer; Forming a metasurface filter layer on the surface of the heat-radiating layer includes: forming a first dielectric layer on the surface of the heat-radiating layer; forming a metal layer on the surface of the first dielectric layer, the metal layer comprising a plurality of first metal units and a plurality of second metal units located on the same layer, the first metal units being assembled from a plurality of arrayed first metal structures, and the first metal structures having a plurality of first vias, the second metal units being assembled from a plurality of arrayed second metal structures, and the second metal structures having a plurality of second vias, the topology of the first metal structures being the same as that of the second metal structures, the period length of the first metal structures being different from that of the second metal structures, and the size of the first vias being different from that of the second vias; forming a second dielectric layer on the surface of the metal layer and on the exposed surface of the first dielectric layer, the first dielectric layer and the second dielectric layer constituting a dielectric layer; An opening is formed in the substrate, the opening penetrating the substrate and exposing the bottom surface of the insulating isolation layer, the opening being located at least below the heat-emitting radiation layer and the metasurface filter layer.

[0016] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: In an infrared light source structure provided by the technical solution of this invention, a substrate, an opening, an insulating layer, a heating and radiating layer, and a metasurface filtering layer are included. The metasurface filtering layer includes a dielectric layer and a metal layer encapsulated by the dielectric layer. The metal layer includes a plurality of first metal units and a plurality of second metal units located on the same layer. The first metal units are assembled from a plurality of first metal structures arranged in an array, and each first metal structure has a plurality of first through-holes filled by the dielectric layer. The second metal units are assembled from a plurality of second metal structures arranged in an array, and each second metal structure has a plurality of second through-holes filled by the dielectric layer. Therefore, both the first and second metal units are periodic arrays of openings. Based on this, since the topology of the first metal structure is the same as that of the second metal structure, the period length of the first metal structure is different from that of the second metal structure, and the size of the first through-hole is different from that of the second through-hole, this infrared light source structure can emit two narrowband infrared radiations with different wavelengths. Since the two narrowband infrared radiations of different wavelengths generated can be directly acquired by the infrared detector in the gas sensor without additional processing, on the one hand, no additional processing devices are needed, simplifying the structure and improving the energy utilization rate of infrared radiation; on the other hand, the two different wavelengths of infrared radiation generated also make the infrared light source structure more widely applicable.

[0017] The gas sensor provided by the present invention includes a gas chamber, an infrared light source structure, and an infrared detector. The infrared light source structure is located at the incident end of the gas chamber and emits first infrared radiation with a first center wavelength and second infrared radiation with a second center wavelength, the first and second center wavelengths being unequal. The infrared detector is located at the receiving end of the gas chamber. The first and second infrared radiation emitted by the infrared light source structure are absorbed by the gas to be measured within the gas chamber and then emitted through the receiving end. The first and second infrared radiations, after being absorbed by the gas to be measured, are acquired by the infrared detector. Since the gas to be measured absorbs the energy of infrared radiation of the corresponding wavelength, the concentration of the gas to be measured in the gas chamber can be inferred from the energy information acquired by the infrared detector. Because the infrared radiation emitted by the infrared light source structure only passes through the gas to be measured in the gas chamber, the energy of the infrared radiation acquired by the infrared detector is relatively high, thereby improving the energy utilization rate of the infrared radiation and the detection accuracy of the infrared detector.

[0018] Furthermore, due to the first center wavelength Second center wavelength satisfy: That is, the first infrared radiation and the second infrared radiation are two independent narrow-band infrared radiations in the spectrum, which allows for precise matching of the wavelengths corresponding to the characteristics of gas molecules, effectively reducing noise and interference from other clutter peaks, thereby enabling the distinction between the energy information of the first infrared radiation and the energy information of the second infrared radiation detected by the infrared detector.

[0019] The present invention provides a gas concentration measurement method, comprising: acquiring initial energy information of a first infrared radiation with a first center wavelength and a second infrared radiation with a second center wavelength emitted by an infrared light source structure; acquiring final energy information of the final infrared radiation and the second infrared radiation after energy absorption by the gas to be measured, collected by the infrared detector; and acquiring the concentration of the gas to be measured based on the initial energy information and the final energy information. Since the infrared light source structure can emit two infrared radiations with different center wavelengths (first and second infrared radiation), a single infrared light source structure can be used to detect two gases, thereby improving detection efficiency and reducing costs. Furthermore, since the first and second infrared radiations only pass through the gas to be measured, the energy of either the first or second infrared radiation passing through the gas to be measured is relatively high, thereby improving energy utilization and the accuracy of gas concentration detection. Attached Figure Description

[0020] Figure 1 It is an infrared light source structure; Figure 2 It includes Figure 1 A gas sensor with an infrared light source structure; Figure 3 yes Figure 2 The spectrum of infrared radiation emitted by the infrared light source structure in the image; Figure 4 yes Figure 2 The spectrum of infrared radiation emitted by the infrared light source structure in the image after absorption by the gas to be measured; Figure 5 yes Figure 2 The infrared radiation emitted by the infrared light source structure in the image is absorbed by the gas to be measured and then filtered, forming a spectrum. Figures 6-12 These are schematic cross-sectional views of each step in the preparation method of the infrared light source structure provided in this embodiment of the invention. Figure 13 This is a schematic diagram of the topology of the first metal structure provided in an embodiment of the present invention; Figure 14 This is a schematic diagram of the topology of the second metal structure provided in an embodiment of the present invention; Figure 15 This is a schematic diagram of the splicing method of the first metal unit and the second metal unit in the metal layer provided in the embodiment of the present invention; Figure 16 This is a filtering effect diagram of the first metal unit provided in an embodiment of the present invention; Figure 17 This is a filtering effect diagram of the second metal unit provided in an embodiment of the present invention; Figure 18 The embodiments of the present invention include Figure 12 Gas sensors with infrared light source structures; Figure 19 The embodiments of the present invention are based on Figure 18 A flowchart of the gas concentration measurement method using a gas sensor in the diagram; Figure 20 yes Figure 18 The spectrum of infrared radiation emitted by the infrared light source structure in the image; Figure 21 yes Figure 18 The spectrum of infrared radiation emitted by the infrared light source structure in the image after absorption by the first gas to be measured; Figure 22 yes Figure 18 The spectrum of infrared radiation emitted by the infrared light source structure in the image after absorption by the second gas to be measured.

[0021] Figure label: 1. Substrate; 2. Insulation layer; 3. Heating and radiating layer; 41. First dielectric layer; 42. Second dielectric layer; 4. Dielectric layer; 5. Metal layer; 510. First metal structure; 520. Second metal structure; 501, First through hole; 502, Second through hole; 6. Draw out the groove; 61. Lead-out electrodes; 7. Opening; 8. Passivation layer; 9. Connecting groove; 51. First metallic unit; 52. Second metal unit. Detailed Implementation

[0022] As described in the background section, when a MEMS infrared light source is used as a gas sensor light source, the infrared energy after passing through the filter is weak, resulting in low energy utilization and thus reduced detection accuracy.

[0023] The following combination Figures 2-5 The method for measuring the concentration of a gas to be measured using a gas sensor is explained in detail.

[0024] Figure 2 It includes Figure 1 A gas sensor with an infrared light source structure. Figure 3 yes Figure 2 The spectrum of infrared radiation emitted by the infrared light source structure in the image. Figure 4 yes Figure 2 The spectrum of infrared radiation emitted by the infrared light source structure in the image after absorption by the gas being measured. Figure 5 yes Figure 2 The infrared radiation emitted by the infrared light source structure is analyzed, and its spectrum is obtained after absorption by the gas being measured and filtering. Among these parameters, Figures 3-5 The horizontal axis represents wavelength, and the vertical axis represents energy.

[0025] Please refer to Figure 3 Infrared light sources produce infrared radiation with a wide wavelength range. After the infrared radiation emitted by the source enters the gas chamber, the gas being tested resonates with the infrared radiation of a specific wavelength and absorbs its energy. Please refer to [reference needed]. Figure 4 , Figure 4 The curve shows a dip, indicating that a portion of the infrared radiation at the wavelength corresponding to the dip is absorbed by the gas being tested. Since the amount of energy absorbed by the gas being tested is related to its concentration, the concentration of the gas can be determined by observing the change in infrared radiation energy at the corresponding wavelength. To facilitate analysis of the change in infrared radiation energy at the corresponding wavelength, a filter is needed to filter the infrared light at the wavelength corresponding to the gas being tested. Please refer to the image for the spectrum after filtering the infrared light at the wavelength corresponding to the gas being tested using a filter. Figure 5 The infrared radiation after passing through the filter has lower energy, meaning the effective energy of the infrared radiation is low, resulting in low energy utilization. Furthermore, the low effective energy of the infrared radiation leads to a reduced signal-to-noise ratio, thus decreasing the detection accuracy of the infrared detector and consequently the gas sensor. In addition, because the filter cannot be integrated with existing MEMS chip processes and its large size requires additional packaging, the cost of the gas sensor is high.

[0026] In view of this, the present invention creatively proposes an infrared light source structure, comprising: a substrate; an opening located within the substrate and penetrating the substrate; an insulating isolation layer located on the top surface of the substrate and the opening, the opening exposing the bottom surface of the insulating isolation layer; a heat-emitting radiation layer located at least above the top surface of the insulating isolation layer above the opening; and a metasurface filtering layer located at least above the surface of the heat-emitting radiation layer above the opening. The metasurface filtering layer includes a dielectric layer and a metal layer encapsulated by the dielectric layer. The metal layer includes a plurality of first metal units and a plurality of second metal units located in the same layer. The first metal units are assembled from a plurality of first metal structures arranged in an array, and the first metal structures have a plurality of first through-holes filled by the dielectric layer. The second metal units are assembled from a plurality of second metal structures arranged in an array, and the second metal structures have a plurality of second through-holes filled by the dielectric layer. The topology of the first metal structures is the same as that of the second metal structures, the period length of the first metal structures is different from that of the second metal structures, and the size of the first through-holes is different from that of the second through-holes.

[0027] This infrared light source structure can emit two narrowband infrared radiations with different wavelengths. Since the energy information of the two narrowband infrared radiations with different wavelengths can be directly obtained by the infrared detector in the gas sensor without additional processing, on the one hand, no additional processing devices are needed, simplifying the structure and improving the energy utilization rate of infrared radiation; on the other hand, the generation of two different wavelengths of infrared radiation also makes the infrared light source structure more widely applicable.

[0028] The embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The terms "first," "second," "third," etc., in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the present invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] Please refer to Figures 6-12 This invention provides a method for preparing an infrared light source structure.

[0030] Please refer to Figure 6 Substrate 1 is provided.

[0031] In this embodiment, substrate 1 may be, for example, a silicon substrate. Of course, in other embodiments, substrate 1 may also be a germanium substrate, a germanium-silicon substrate, etc.

[0032] Please refer to Figure 6 An insulating isolation layer 2 is formed on the surface of substrate 1.

[0033] In this embodiment, the material of the insulating layer 2 can be, for example, silicon oxide or silicon nitride. The insulating layer 2 is located between the substrate 1 and the subsequently formed heat-emitting layer 3 to isolate the conductive substrate 1 from the heat-emitting layer 3, prevent current leakage in the heat-emitting layer 3, and ensure the safety and stability of the infrared light source structure.

[0034] Please refer to Figure 7 A heat-generating radiation layer 3 is formed on the surface of the insulating layer 2.

[0035] Among them, the heating and radiation layer 3 covers part of the surface of the insulating layer 2.

[0036] In this embodiment, the material of the heating and radiating layer 3 may be, for example, any one of doped polycrystalline silicon, tungsten, and platinum.

[0037] Please refer to Figures 8-10 A metasurface filter layer is formed on the surface of the heating and radiation layer 3.

[0038] In this embodiment, the method for forming the metasurface filter layer may include: Please refer to Figure 8 A first dielectric layer 41 is formed on the surface of the heating and radiating layer 3, and the first dielectric layer 41 covers the surface of the heating and radiating layer 3 and the surface of the insulating isolation layer 2 that is not covered by the heating and radiating layer 3.

[0039] For further information, please refer to [link / reference]. Figure 9 A metal layer 5 is formed on the surface of the first dielectric layer 41. The metal layer 5 is located on a portion of the surface of the first dielectric layer 41, and the projection of the metal layer 5 onto the substrate is located within the projection area of ​​the heating and radiating layer 3 onto the substrate.

[0040] In this embodiment, in conjunction with reference Figure 9 , Figure 13 , Figure 14 and Figure 15 The metal layer 5 may include a plurality of first metal units 51 and a plurality of second metal units 52 located in the same layer.

[0041] The first metal unit 51 is formed by splicing together multiple first metal structures 510 arranged in an array, and the first metal structure 510 has multiple first through holes 501. The second metal unit 52 is formed by splicing together multiple second metal structures 520 arranged in an array, and the second metal structure 520 has multiple second through holes 502.

[0042] In this embodiment, the topology of the first metal structure 510 is the same as that of the second metal structure 520, the period length of the first metal structure 510 is different from that of the second metal structure 520, and the size of the first through hole 501 is different from that of the second through hole 502.

[0043] In one specific embodiment, topology refers to the physical layout of the metal structure, which may specifically include the projected shape of the metal structure, the projected shape of the through holes, and the positional relationship of the through holes in the metal structure. Period length refers to the periodic unit characteristic of a single metal structure that makes up the metal unit, which may specifically include the side length of the metal structure and the size of the through holes in the metal structure.

[0044] In this embodiment, please refer to Figure 10 A second dielectric layer 42 is formed on the surface of the metal layer 5 and the exposed surface of the first dielectric layer 41, and both the first via 501 and the second via 502 are filled by the second dielectric layer 42. The first dielectric layer 41 and the second dielectric layer 42 constitute the dielectric layer 4. In this embodiment, the dielectric layer 4 and the metal layer 5 constitute the metasurface filter layer of the infrared light source structure. The metasurface filter layer can filter the infrared radiation emitted by the heating radiation layer 3, so that the infrared radiation passing through the metasurface filter layer is two narrowband infrared radiations with different wavelengths.

[0045] Furthermore, after forming the metasurface filtering layer, the fabrication method of this infrared light source structure may also include: Please refer to... Figure 10 The dielectric layer 4 is etched to form an lead-out groove 6, and the bottom surface of the lead-out groove 6 exposes the heat radiation layer 3.

[0046] In this embodiment, please refer to Figure 11 An outgoing electrode 61 is formed in the outgoing groove 6 and on the surface of the second dielectric layer 42 near the outgoing groove 6.

[0047] Furthermore, after forming the lead-out electrode 61, a passivation material layer (not shown) is formed on the surface of the second dielectric layer 42 and the surface of the lead-out electrode 61.

[0048] In this embodiment, a connection groove 9 is formed in the passivation material layer, and the bottom surface of the connection groove 9 exposes the lead-out electrode 61. At the same time, the passivation material layer above the heating radiation layer 3 is removed to expose the top surface of the second dielectric layer 42 to form a passivation layer 8.

[0049] Specifically, the external drive circuit can be electrically connected to the lead-out electrode 61 through the connecting groove 9, that is, the lead-out electrode 61 can pass a drive current to the heating radiation layer 3 to heat the heating radiation layer 3 and make it emit infrared radiation.

[0050] The passivation layer 8 can be, for example, a low-stress silicon nitride thin film, and the passivation layer 8 is used to protect the lead electrode 61.

[0051] In this embodiment, the material of the dielectric layer 4 may be any one of silicon dioxide, silicon nitride, and silicon oxynitride, and the material of the metal layer 5 may be any one of gold, silver, and copper.

[0052] Please refer to Figure 12 An opening 7 is formed in the substrate 1, the opening 7 penetrates the substrate 1 and exposes the bottom surface of the insulating isolation layer 2, and the opening 7 is located at least below the heat radiation layer 3 and the metasurface filter layer.

[0053] Specifically, a portion of the substrate 1 is removed along the direction away from the insulating isolation layer 2 to form an opening 7 in the substrate 1.

[0054] Please refer to Figure 12 This invention also provides an infrared light source structure, which is obtained using the above-described method for fabricating an infrared light source. The infrared light source structure may include a substrate 1, an opening 7, an insulating layer 2, a heating and radiating layer 3, and a metasurface filtering layer.

[0055] The opening 7 is located inside the substrate 1 and extends through the substrate 1.

[0056] In this embodiment, the insulating isolation layer 2 is located on the top surface of the substrate 1 and the opening 7, with the opening 7 exposing the bottom surface of the insulating isolation layer 2.

[0057] In this embodiment, the heat-radiating layer 3 is located at least on the top surface of the insulating layer 2 above the opening 7.

[0058] In this embodiment, the metasurface filter layer is located at least on the surface of the heat-radiating layer 3 above the opening 7.

[0059] In this embodiment, the metasurface filter layer may include a dielectric layer 4 and a metal layer 5 encased by the dielectric layer 4. The metal layer 5 may include a plurality of first metal units 51 and a plurality of second metal units 52 located on the same layer. The first metal unit 51 is formed by splicing together a plurality of first metal structures 510 arranged in an array, and the first metal structure 510 has a plurality of rotationally symmetric first vias 501 filled by the dielectric layer 4. The second metal unit 52 is formed by splicing together a plurality of second metal structures 520 arranged in an array, and the second metal structure 520 has a plurality of second vias 502 filled by the dielectric layer 4. The topology of the first metal structure 510 is the same as that of the second metal structure 520, but the period length of the first metal structure 510 is different from that of the second metal structure 520, and the size of the first via 501 is different from that of the second via 502.

[0060] The metasurface filter layer is used to convert the broad infrared radiation generated by the heating radiation layer into two narrow-band infrared radiations with different wavelengths.

[0061] In this embodiment, the plurality of first through holes 501 within the first metal structure 510 are arranged in a rotationally symmetrical manner, and the plurality of second through holes 502 within the second metal structure 520 are arranged in a rotationally symmetrical manner. For example, please refer to... Figure 13 and Figure 14 The first metal structure 510 has four 90° rotationally symmetrical first through holes 501 filled with dielectric layer 4, and the second metal structure 520 has four 90° rotationally symmetrical second through holes 502 filled with dielectric layer 4.

[0062] In this embodiment, the topology of the first metal structure 510 is the same as that of the second metal structure 520, specifically: the vertical projection of the first metal structure 510 on the heating and radiating layer 3 and the vertical projection of the second metal structure 520 on the heating and radiating layer 3 have the same shape; the center O1 of the first metal structure 510 is the rotation center corresponding to a plurality of first through holes 501; the center O2 of the second metal structure 520 is the rotation center corresponding to a plurality of second through holes 502; the vertical projection of the first through hole 501 on the heating and radiating layer 3 and the vertical projection of the second through hole 502 on the heating and radiating layer 3 have the same shape; and the shape of the vertical projection of the first through hole 501 on the heating and radiating layer 3 is elliptical or rectangular.

[0063] In this embodiment, the vertical projections of both the first through hole 501 and the second through hole 502 are square. Of course, in other embodiments, the vertical projections of the first through hole 501 and the second through hole 502 can be other shapes. Those skilled in the art can design the shapes of the vertical projections of the first through hole 501 and the second through hole 502 according to actual needs, and the present invention does not limit this.

[0064] Please refer to the following: Figure 13 and Figure 14 The differences between the first metal structure 510 and the second metal structure 520 are as follows: 1. The period lengths of the first metal structure 510 and the second metal structure 520 are different. Since the vertical projections of the first metal structure 510 and the second metal structure 520 onto the heating and radiating layer 3 are both square, specifically, the side length P1 of the first metal structure 510 and the side length P2 of the second metal structure 520 are different; 2. The sizes of the first through hole 501 and the second through hole 502 are different. For example, if the first through hole 501 is on the heating and radiating layer 3... The vertical projections of the first through-hole 501 and the second through-hole 502 onto the heating radiation layer 3 are both elliptical in shape. Their dimensions include the semi-major axis and semi-minor axis of the ellipse. Specifically, the semi-major axis a1 of the first through-hole 501 is not equal to the semi-major axis a2 of the second through-hole 502, and the semi-minor axis b1 of the first through-hole 501 is not equal to the semi-minor axis b2 of the second through-hole 502. 3. The distance d1 between the center O1 of the first metal structure 510 and the center of the first through-hole 501 is different from the distance d2 between the center O2 of the second metal structure 520 and the center of the second through-hole 502. These differences are all set by technicians according to a preset center wavelength.

[0065] In this embodiment, the thickness of the metal layer 5 ranges from 100nm to 200nm, and the thickness of the dielectric layer 4 ranges from 500nm to 600nm.

[0066] In this embodiment, please refer to Figure 15 The first metal unit 51 and the second metal unit 52 in the metal layer 5 are arranged in an array, and the first metal unit 51 and the second metal unit 52 are alternately spliced, so that the arrangement between the first metal unit 51 and the second metal unit 52 is still periodic, thereby ensuring that the infrared response is basically consistent everywhere.

[0067] Specifically, the side length of the first metal unit 51 and the side length of the second metal unit 52 need to be close. That is, the side length P1 of m times the first metal structure 510 needs to be close to the side length P2 of n times the second metal structure 520. For example, the first metal unit 51 includes m×m first metal structures 510, and the second metal unit 52 includes n×n second metal structures 520, where m and n are both positive integers. When the side length of the first metal structure 510 is 4.05μm and the side length of the second metal structure 520 is 4.48μm, m=11 and n=10 can be set. However, the side length of the first metal unit 51 (i.e., mP1) and the side length of the second metal unit 52 (i.e., nP2) cannot be exactly the same. Therefore, the part of the first metal unit 51 and the second metal unit 52 that is not aligned during splicing is still the dielectric layer 4.

[0068] In one specific embodiment, the metal layer 5 is made of silver and has a thickness of 120 nm, while the dielectric layer 4 is made of silicon dioxide and has a thickness of 500 nm. Please refer to [reference needed]. Figure 13 The center wavelength of the first metal structure 510 is 4.26 μm, the side length P1 of the first metal structure 510 is set to 4.05 μm, the semi-major axis a1 of the first through hole 501 is 550 nm, the semi-minor axis b1 of the first through hole 501 is 440 nm, and the distance d1 between the center of the first through hole 501 and the center O1 of the first metal structure 510 is 1.15 μm. Based on this, please refer to... Figure 16 , Figure 16 The diagram shows the filtering effect of the first metal unit 51. The horizontal axis represents wavelength, and the vertical axis represents reflectivity or transmittance. The dashed curve represents the reflectivity of the first metal unit for each wavelength of infrared radiation, and the solid curve represents the transmittance of the first metal unit for each wavelength of infrared radiation. The first metal unit 51 has narrowband transmission characteristics, with a reflectivity of less than 5%, a transmittance of 70%, and a transmission spectral linewidth of less than 0.1 μm.

[0069] Please continue to refer to this. Figure 14 The center wavelength of the second metal structure 520 is 4.67 μm, the side length P2 of the second metal structure 520 is set to 4.48 μm, the semi-major axis a2 of the second through hole 502 is 610 nm, the semi-minor axis b2 of the second through hole 502 is 470 nm, and the distance d2 between the center of the second through hole 502 and the center O2 of the second metal structure 520 is 1.27 μm. Based on this, please refer to... Figure 17 , Figure 17 The diagram shows the filtering effect of the second metal unit 52. The horizontal axis represents wavelength, and the vertical axis represents reflectance or transmittance. The dashed curve represents the reflectance of the second metal unit 52 for each wavelength of infrared radiation, and the solid curve represents the transmittance of the second metal unit 52 for each wavelength of infrared radiation. The second metal unit 52 has narrowband transmission characteristics, with a reflectance of less than 5%, a transmittance of 70%, and a transmission spectral linewidth of less than 0.1 μm.

[0070] In this embodiment, please refer to Figure 12 The infrared light source structure may further include: an extraction electrode 61, a passivation layer 8, and a connecting groove 9. The extraction electrode 61 is located within the second dielectric layer 42 and on a portion of the surface of the second dielectric layer 42, and the bottom of the extraction electrode 61 is electrically connected to the infrared radiation layer 3. The passivation layer 8 is located on the surface of the second dielectric layer 42 and the surface of the extraction electrode 61. The connecting groove 9 is located within the passivation layer 8, and the bottom of the connecting groove 9 exposes the extraction electrode 61.

[0071] The materials, formation process, working principle, specific implementation method and beneficial effects of the infrared light source structure in the embodiments of the present invention can be found in the preparation method of the infrared light source structure in the embodiments of the present invention, and will not be repeated here.

[0072] In summary, the infrared light source structure provided in this embodiment of the invention can emit narrowband infrared radiation of two adjacent wavelengths. Since the energy information of the two narrowband infrared radiations with different wavelengths generated can be directly obtained by the infrared detector in the gas sensor without additional processing, on the one hand, no additional processing devices are required, simplifying the structure and improving the energy utilization rate of infrared radiation; on the other hand, the generation of two different wavelengths of infrared radiation also makes the infrared light source structure more widely applicable.

[0073] Please refer to Figure 18 The present invention also provides a gas sensor, which may include: a gas chamber, the above-mentioned infrared light source structure and infrared detector structure.

[0074] The infrared light source structure is used to emit a first infrared radiation with a first center wavelength and a second infrared radiation with a second center wavelength, wherein the first center wavelength and the second center wavelength are not equal.

[0075] In this embodiment, the gas chamber is used to contain the gas to be tested, and the gas chamber has an incident end and a receiving end. The infrared light source structure is located at the incident end of the gas chamber, and the first infrared radiation and the second infrared radiation are emitted through the receiving end after the gas to be tested in the gas chamber absorbs energy.

[0076] In this embodiment, the first center wavelength and the second center wavelength satisfy: ,in, The first center wavelength, This is the second center wavelength. Specifically, if... >2 or That is, the first center wavelength With the second center wavelength The large difference between them leads to a large design difference between the corresponding first metal structure 510 and the second metal structure 520, which in turn destroys the filtering function of the metasurface filter layer and brings additional light diffraction.

[0077] In this embodiment, the spectral signals of the first infrared radiation and the second infrared radiation do not overlap. Specifically, the effective spectral range based on the first center wavelength and the effective spectral range based on the second center wavelength do not intersect. The effective spectral range based on the first center wavelength is the interval comprised of all wavelengths of the first infrared radiation whose energy intensity is greater than or equal to 50% of the energy intensity corresponding to the first center wavelength, and the effective spectral range based on the second center wavelength is the interval comprised of all wavelengths of the second infrared radiation whose energy intensity is greater than or equal to 50% of the energy intensity corresponding to the second center wavelength.

[0078] In this embodiment, the infrared detector is located at the receiving end of the gas chamber. The infrared detector is used to acquire the first infrared radiation and the second infrared radiation after the gas to be tested has absorbed energy.

[0079] In the gas sensor provided in this embodiment of the invention, since the infrared radiation emitted by the infrared light source structure only passes through the gas to be measured in the gas chamber, the infrared detector acquires higher energy of the infrared radiation, thereby improving the energy utilization rate of the infrared radiation and the detection accuracy of the infrared detector.

[0080] Furthermore, due to the first center wavelength Second center wavelength satisfy: That is, the first infrared radiation and the second infrared radiation are two independent narrow-band infrared radiations in the spectrum, which allows for precise matching of the wavelengths corresponding to the characteristics of gas molecules, effectively reducing noise and interference from other clutter peaks, thereby enabling the distinction between the energy information of the first infrared radiation detected by the infrared detector and the energy information of the second infrared radiation.

[0081] Please refer to the reference. Figure 18 and Figure 19 The present invention also provides a gas concentration measurement method, which is applied to the above-mentioned gas sensor.

[0082] Specifically, the gas concentration measurement method may include: S1, acquire the initial energy information of the first infrared radiation with a first center wavelength and the second infrared radiation with a second center wavelength emitted by the infrared light source structure.

[0083] In this embodiment, please refer to Figure 20 In S1, the aforementioned infrared light source structure is capable of emitting two easily distinguishable, narrow-band first and second infrared radiations. As an example, in... Figure 20 In this case, the first center wavelength is smaller than the second center wavelength.

[0084] S2, acquire the final energy information of the first and second infrared radiations after the energy is absorbed by the gas to be tested, collected by the infrared detector.

[0085] In this embodiment, the energy of the first infrared radiation can be absorbed by the first gas to be tested, and the second infrared radiation can be absorbed by the second gas to be tested. The first gas to be tested and the second gas to be tested are of different types.

[0086] As a specific embodiment, the first gas to be tested is carbon dioxide, which can absorb infrared radiation with a center wavelength of 4.26 μm, and the second gas to be tested is carbon monoxide, which can absorb infrared radiation with a center wavelength of 4.67 μm.

[0087] S3. Based on the initial energy information and the final energy information, obtain the concentration of the gas to be tested.

[0088] In this embodiment, please refer to Figure 20 and Figure 21 When the gas to be tested in the gas chamber is the first gas to be tested, after the first infrared radiation and the second infrared radiation pass through the first gas to be tested, the energy of the first infrared radiation is significantly reduced, meaning that the first gas to be tested can absorb the energy of the first infrared radiation. Since the first gas to be tested can absorb part of the energy of the first infrared radiation, the concentration of the first gas to be tested can be obtained based on the initial energy information and the final energy information of the first infrared radiation.

[0089] In this embodiment, please refer to Figure 20 and Figure 22 When the gas to be tested in the gas chamber is the second gas, the energy of the second infrared radiation decreases significantly after passing through it, meaning the second gas can absorb some of the energy of the second infrared radiation. Since the second gas can absorb a portion of the energy of the second infrared radiation, its concentration can be obtained based on the initial and final energy information of the second infrared radiation.

[0090] The gas concentration measurement method provided in this embodiment of the invention includes: acquiring initial energy information of a first infrared radiation with a first center wavelength and a second infrared radiation with a second center wavelength emitted by an infrared light source structure; acquiring final energy information of the final infrared radiation and the second infrared radiation after the energy is absorbed by the gas to be measured, collected by the infrared detector; and acquiring the concentration of the gas to be measured based on the initial energy information and the final energy information. Since the infrared light source structure can emit two infrared radiations with different center wavelengths (first and second infrared radiation), a single infrared light source structure can be used to detect two gases, thereby improving detection efficiency and reducing costs. Furthermore, since the first and second infrared radiations only pass through the gas to be measured, the energy of either the first or second infrared radiation passing through the gas to be measured is relatively high, thereby improving energy utilization and the accuracy of gas concentration detection.

[0091] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An infrared light source structure, characterized by, include: Substrate; An opening is located within the substrate and extends through the substrate; An insulating layer is located on the top surface of the substrate and an opening that exposes the bottom surface of the insulating layer. A heat-radiating layer, at least located on the top surface of an insulating layer above the opening; A metasurface filter layer, located at least above the surface of the heat-radiating layer above the opening, comprises a dielectric layer and a metal layer encapsulated by the dielectric layer. The metal layer comprises a plurality of first metal units and a plurality of second metal units located on the same layer. The first metal units are assembled from a plurality of first metal structures arranged in an array, and the first metal structures have a plurality of first through-holes filled by the dielectric layer. The second metal units are assembled from a plurality of second metal structures arranged in an array, and the second metal structures have a plurality of second through-holes filled by the dielectric layer. The topology of the first metal structures is the same as that of the second metal structures, but the period length of the first metal structures is different from that of the second metal structures, and the size of the first through-holes is different from that of the second through-holes.

2. The infrared light source structure according to claim 1, wherein The vertical projections of the first metal structure and the second metal structure on the heat-radiating layer have the same shape, and the vertical projections of the first through hole and the second through hole on the heat-radiating layer have the same shape.

3. The infrared light source structure according to claim 1, characterized in that, The thickness of the metal layer ranges from 100nm to 200nm, and the thickness of the dielectric layer ranges from 500nm to 600nm.

4. The infrared light source structure according to claim 1, characterized in that, The dielectric layer is made of any one of silicon dioxide, silicon nitride, and silicon oxynitride; the metal layer is made of any one of gold, silver, and copper; the insulating layer is made of silicon oxide or silicon nitride; and the heating and radiating layer is made of any one of doped polycrystalline silicon, tungsten, and platinum.

5. The infrared light source structure according to claim 1, characterized in that, The first metal unit and the second metal unit in the metal layer are arranged in an array, and the first metal unit and the second metal unit are alternately spliced ​​together.

6. The infrared light source structure according to claim 1, characterized in that, The plurality of first through holes in the first metal structure are arranged in rotational symmetry, and the plurality of second through holes in the second metal structure are arranged in rotational symmetry. The center of the first metal structure is the rotation center of the plurality of first through holes, and the center of the second metal structure is the rotation center of the plurality of second through holes.

7. A gas sensor, characterized in that, include: The infrared light source structure according to any one of claims 1 to 6 is used to emit a first infrared radiation having a first center wavelength and a second infrared radiation having a second center wavelength, wherein the first center wavelength and the second center wavelength are not equal; A gas chamber is used to contain the gas to be tested; the gas chamber has an incident end and a receiving end, the infrared light source structure is located at the incident end of the gas chamber, and the first infrared radiation and the second infrared radiation are emitted through the receiving end after the gas to be tested absorbs energy in the gas chamber; an infrared detector is located at the receiving end of the gas chamber and is used to acquire the first infrared radiation and the second infrared radiation after the gas to be tested absorbs energy.

8. The gas sensor according to claim 7, characterized in that, The first center wavelength and the second center wavelength satisfy: ,in, The first center wavelength, This is the second center wavelength.

9. A method for measuring gas concentration, characterized in that, Based on the gas sensor as described in claim 7 or 8, comprising: Acquire the initial energy information of the first infrared radiation with a first center wavelength and the second infrared radiation with a second center wavelength emitted by the infrared light source structure; The final energy information of the first and second infrared radiations after the gas to be tested has absorbed energy is obtained from the infrared detector. The concentration of the gas to be tested is obtained based on the initial energy information and the final energy information.

10. A method for fabricating an infrared light source structure, characterized in that, include: Provide substrate; An insulating layer is formed on the surface of the substrate; A heat-radiating layer is formed on the surface of the insulating layer; Forming a metasurface filter layer on the surface of the heat-radiating layer includes: forming a first dielectric layer on the surface of the heat-radiating layer; forming a metal layer on the surface of the first dielectric layer, the metal layer including a plurality of first metal units and a plurality of second metal units located on the same layer, the first metal units being assembled from a plurality of first metal structures arranged in an array, and the first metal structures having a plurality of first vias, the second metal units being assembled from a plurality of second metal structures arranged in an array, and the second metal structures having a plurality of second vias, the topology of the first metal structures being the same as that of the second metal structures, the period length of the first metal structures being different from that of the second metal structures, and the size of the first vias being different from that of the second vias; forming a second dielectric layer on the surface of the metal layer and the exposed surface of the first dielectric layer, the second dielectric layer further filling the first vias and the second vias, the first dielectric layer and the second dielectric layer constituting a dielectric layer; An opening is formed in the substrate, the opening penetrating the substrate and exposing the bottom surface of the insulating isolation layer, the opening being located at least below the heat-emitting radiation layer and the metasurface filter layer.

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