Infrared detector

Abstract

The utility model relates to the field of infrared detection, in particular to an infrared detector, which sequentially comprises a reflecting layer, a supporting layer, a thermosensitive film layer, a thermosensitive protective layer and a conductive resonance layer from bottom to top, the reflecting layer and the supporting layer are arranged at an interval, and a resonant cavity is formed between the reflecting layer and the supporting layer; the conductive resonance layer comprises a resonance pattern, the resonance pattern is a pattern formed by resonance lines, and the resonance lines are lines comprising broken areas. Due to the fact that a broken area exists between the resonance lines, strong infrared electromagnetic wave resonance can occur in the broken area, the near-field electric field intensity is greatly enhanced, under the condition that the dielectric loss of a material is fixed, the higher the near-field electric field intensity is, the higher the electromagnetic loss is, and finally absorption of an electromagnetic field is greatly enhanced. And the conductive resonance layer is small in occupied space, relatively simple in structure and extremely easy to integrate with a related uncooled infrared pixel structure based on a thermosensitive thin film material, so that the production cost is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the field of infrared detection, in particular to an infrared detector. Background Art

[0002] Any object above absolute zero will emit infrared rays, which carry a wealth of information about the object. Since human eyes cannot see infrared rays, we need infrared detectors based on thermal imaging technology to detect infrared rays. With the development of thermal imaging technology, the pixel structure of infrared detectors is moving towards small size and high performance. However, the reduction in pixel size will lead to a reduction in infrared absorption, thereby reducing the performance of infrared detectors.

[0003] Among them, the metal-dielectric-metal structure (MIM structure) is a widely used infrared absorption structure based on surface plasmon resonance. Its basic structure is as follows: the bottom layer is a continuous metal film layer, the middle layer is a low-loss dielectric layer, and the top layer is a patterned metal layer. Its principle is that the incident electromagnetic wave excites a reverse current pair in the top metal and bottom metal in the MIM structure, forming a strong magnetic resonance, thereby strongly absorbing the incident wave. Different absorption frequencies can be controlled by adjusting the size of the top patterned metal.

[0004] However, this infrared absorption structure has a complex longitudinal structure and is relatively thick. The infrared detector using this structure has a large thermal mass, which results in a longer thermal response time of the detector and reduced detection performance.

[0005] Therefore, how to improve the infrared absorption capability of the infrared detector pixel structure while shortening the thermal response time of the detector and reducing the space occupied by the detector is an urgent problem to be solved by those skilled in the art. Utility Model Content

[0006] The utility model aims to provide an infrared detector to solve the problems of poor infrared absorption capability, long thermal response time and large occupied space of the infrared detector in the prior art.

[0007] In order to solve the above technical problems, the utility model provides an infrared detector, which comprises a reflective layer, a support layer, a thermosensitive film layer, a thermosensitive protective layer and a conductive resonance layer from bottom to top;

[0008] The reflective layer and the support layer are spaced apart to form a resonant cavity between the reflective layer and the support layer;

[0009] The conductive resonance layer includes a resonance pattern, the resonance pattern is a pattern composed of resonance lines, and the resonance lines are lines including broken areas.

[0010] Optionally, in the infrared detector, a resonance protection layer is also included;

[0011] The resonance protection layer covers the conductive resonance layer.

[0012] Optionally, in the infrared detector, the conductive resonance layer includes a resonance pattern and / or a resonance combination;

[0013] The resonance combination includes a plurality of resonance patterns nested in each other.

[0014] Optionally, in the infrared detector, a plurality of the resonance patterns and / or the resonance combination arrays are arranged.

[0015] Optionally, in the infrared detector, the resonance combination includes at least two nested notched ring resonance patterns;

[0016] The notched ring resonance pattern is a ring pattern including at least one broken region.

[0017] Optionally, in the infrared detector, the resonance combination includes at least two nested rectangular cut resonance patterns;

[0018] The rectangular cut resonance pattern is a rectangular pattern with at least one broken area;

[0019] The sides of the rectangular cut resonant pattern nested inside and the rectangular cut resonant pattern nested outside are parallel to each other.

[0020] Optionally, in the infrared detector, the support layer and / or the heat-sensitive protective layer is an infrared absorption layer.

[0021] Optionally, in the infrared detector, the line width of the resonant line ranges from 0.1 micrometers to 10 micrometers, including endpoint values.

[0022] Optionally, in the infrared detector, the resonance pattern is a groove pattern opened on a continuous conductive resonance layer, and the broken area is a portion of the conductive resonance layer that is not grooved on the resonance line.

[0023] Optionally, in the infrared detector, the groove pattern is a groove pattern whose bottom surface exposes the thermal sensitive protective layer.

[0024] The infrared detector provided by the utility model comprises, from bottom to top, a reflective layer, a support layer, a thermosensitive film layer, a thermosensitive protective layer and a conductive resonance layer; the reflective layer and the support layer are arranged at intervals to form a resonance cavity between the reflective layer and the support layer; the conductive resonance layer comprises a resonance pattern, the resonance pattern is a pattern composed of resonance lines, and the resonance lines are lines including broken areas.

[0025] When the infrared electromagnetic wave is incident on the conductive resonance layer, the free electrons on the surface of the conductive resonance layer are excited by the infrared electromagnetic wave, and the electron movement and the incident infrared photoelectric magnetic field mutually excite each other to produce collective resonance movement. Since there is a broken area between the resonance lines, a strong infrared electromagnetic wave resonance will occur in the broken area, which greatly enhances the near-field electric field strength. When the dielectric loss of the material is fixed, the greater the near-field electric field strength, the higher the electromagnetic loss, which ultimately greatly enhances the absorption of the electromagnetic field. In addition, the conductive resonance layer occupies a small space, has a relatively simple structure, and is very easy to be integrated with related non-cooled infrared pixel structures based on thermosensitive thin film materials, which greatly reduces the production cost and is conducive to the miniaturization of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the utility model or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic structural diagram of a specific implementation of the infrared detector provided by the utility model;

[0028] Figure 2 A schematic structural diagram of a specific implementation of the infrared detector provided by the utility model;

[0029] Figure 3 A top view of the structure of a specific implementation of the infrared detector provided by the utility model;

[0030] Figure 4 A top view of the structure of another specific implementation of the infrared detector provided by the utility model;

[0031] Figure 5 A top view of the structure of another specific implementation of the infrared detector provided by the utility model;

[0032] Figure 6 A structural top view of another specific implementation of the infrared detector provided by the utility model;

[0033] Figure 7 The present invention is a top view of the structure of another specific implementation manner of the infrared detector provided by the present invention.

[0034] In the figure, it includes 1-reflection layer, 2-support layer, 3-resonance cavity, 4-thermosensitive film layer, 5-thermosensitive protection layer, 6-conductive resonance layer, 6'-resonance combination, and 7-resonance protection layer. DETAILED DESCRIPTION

[0035] In recent years, with the rapid development of micro-nano processing technology, research on the various optical properties of metal nano-metamaterials has attracted the attention of countries around the world. The structure formed by metal nano-metamaterials can interact with electromagnetic waves in the optical near field to achieve the manipulation of the electromagnetic field. Using metal nano-metamaterials to reduce reflection and enhance absorption is one of the important solutions to improve the detector response rate. The absorption of electromagnetic waves by general uncooled infrared detectors depends on the properties of the material itself. The introduction of metal microstructures in infrared detectors can stimulate the surface plasmon resonance effect when infrared electromagnetic waves are incident, thereby greatly enhancing the infrared detector's absorption rate of infrared electromagnetic waves.

[0036] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0037] The core of the utility model is to provide an infrared detector, a structural schematic diagram of a specific implementation method is shown in FIG. Figure 1 As shown, it is called the specific implementation mode 1, which includes a reflective layer 1, a support layer 2, a thermosensitive film layer 4, a thermosensitive protective layer 5 and a conductive resonance layer 6 from bottom to top;

[0038] The reflective layer 1 is spaced apart from the support layer 2, and a resonant cavity 3 is formed between the reflective layer 1 and the support layer 2;

[0039] The conductive resonance layer 6 includes a resonance pattern, which is a pattern composed of resonance lines, and the resonance lines are lines including broken areas.

[0040] Specifically, it also includes a resonance protection layer 7;

[0041] The resonance protection layer 7 covers the conductive resonance layer 6 .

[0042] Of course, the function of the resonance protection layer 7 is to further protect the conductive resonance layer 6 from being damaged by external forces, and it needs to be a dielectric material layer with good insulation, such as a silicon nitride layer, a silicon oxide layer, etc. Figure 2 In addition, the structure and materials of the thermosensitive protective layer 5 can also refer to the resonance protective layer 7.

[0043] The reflective layer 1 is a layer with good conductivity, such as a gold layer, an aluminum layer, etc. The support layer 2 is a dielectric material layer with good insulation, such as a silicon nitride layer, a silicon oxide layer, etc., and is used to support other epitaxial structures.

[0044] The thermosensitive film layer 4 is a layer whose resistance value changes with temperature, such as a vanadium oxide layer, an amorphous silicon layer, etc. The temperature rises after absorbing infrared rays of a specific wavelength through other structures in the infrared detector, causing the resistance value of the thermosensitive film layer 4 to change, thereby achieving the purpose of infrared detection.

[0045] Specifically, the conductive resonance layer 6 is a metal resonance layer, which can be a metal single substance layer or a metal compound layer, such as a gold layer, an aluminum layer, a titanium layer, a titanium nitride layer, etc. Metals and metal compounds have strong plasticity, are easy to pattern, and have mature processes, and are easy to promote and put into production on a large scale. Figure 3 It is a structural top view of a specific implementation method of the utility model.

[0046] Further, the line width of the resonant line ranges from 0.1 micrometers to 10 micrometers, including endpoint values, such as any one of 0.10 micrometers, 3.21 micrometers or 10.00 micrometers. The above parameter range is the line width range that can cause infrared resonant motion to the greatest extent after a large number of theoretical calculations and actual tests. Of course, it can also be adjusted according to actual conditions, and the utility model does not limit it again.

[0047] As a preferred embodiment, the conductive resonance layer 6 includes a resonance pattern and / or a resonance combination 6';

[0048] The resonance combination 6' includes a plurality of resonance patterns nested in each other.

[0049] In other words, in this preferred embodiment, there are a plurality of resonant patterns nested in combination (i.e., the resonant combination 6'). Adjacent nested resonant lines can also achieve an effect similar to that of the broken area, resulting in strong infrared electromagnetic resonance, thereby greatly improving the infrared absorption efficiency. Of course, in addition to the nested combination patterns, the conductive resonant layer 6 can also include non-nested resonant patterns at the same time, which can be selected according to actual conditions.

[0050] Of course, as a specific implementation, a plurality of the resonant patterns and / or the resonant combinations 6' are arranged in an array. The infrared detector surface can include an array composed of the resonant patterns and / or the resonant combinations 6', thereby increasing the detection area size of the infrared detector. The array can be composed of only the resonant combinations 6', or only the resonant patterns, or a mixture of the resonant patterns and the resonant combinations 6'. The array can include a plurality of different resonant patterns and / or the resonant combinations 6' (see Figure 6or Figure 7 The third pattern from left to right).

[0051] Specifically, the resonance combination 6' includes at least two nested notched ring resonance patterns;

[0052] The notched ring resonance pattern is a ring pattern including at least one broken region.

[0053] Please refer to Figure 4 , Figure 4 The two annular patterns are nested with each other, and the corresponding broken areas are in opposite directions, which can respectively induce strong infrared electromagnetic resonance in different areas of the infrared detector. At the same time, the circular interval of the two annular patterns can also induce electromagnetic resonance in a circular area. The preferred embodiment has a simple resonant pattern, low production difficulty, high yield, and good infrared absorption effect. Of course, in actual production, different numbers of resonant patterns can be selected for nesting according to actual conditions, such as four or five resonant patterns for nesting, and multiple (such as three or six gaps) can be set on a single resonant pattern according to the situation.

[0054] As another preferred embodiment, the resonance combination 6' comprises at least two nested rectangular cut resonance patterns;

[0055] The rectangular cut resonance pattern is a rectangular pattern with at least one broken area;

[0056] The sides of the rectangular cut resonant pattern nested inside and the rectangular cut resonant pattern nested outside are parallel to each other.

[0057] Please refer to Figure 5 , Figure 5 It is not difficult to see that this preferred embodiment has a large number of broken areas while maintaining a relatively simple graphic, so it can further enhance the infrared electromagnetic resonance effect and further enhance the infrared absorption rate.

[0058] The following provides a specific implementation method of the production method of the infrared detector:

[0059] Step 1: Deposit a reflective layer 1, a sacrificial layer, a support layer 2, a thermosensitive film layer 4, and a thermosensitive protective layer 5 on a substrate in sequence by evaporation, electron beam evaporation, or magnetron sputtering, and pattern the above structures in sequence.

[0060] Step 2: Deposit a conductive resonance layer 6 on the above structure by evaporation, electron beam evaporation or magnetron sputtering, and pattern the conductive resonance layer 6 structure.

[0061] Step 3: If necessary, a resonance protection layer 7 may be deposited on the patterned conductive resonance layer 6 .

[0062] Step 4: Release the sacrificial layer.

[0063] The infrared detector provided by the utility model includes, from bottom to top, a reflective layer 1, a support layer 2, a thermosensitive film layer 4, a thermosensitive protective layer 5 and a conductive resonance layer 6; the reflective layer 1 and the support layer 2 are arranged at intervals, and a resonance cavity 3 is formed between the reflective layer 1 and the support layer 2; the conductive resonance layer 6 includes a resonance pattern, and the resonance pattern is a pattern composed of resonance lines, and the resonance lines are lines including broken areas. When infrared electromagnetic waves are incident on the conductive resonance layer 6, the free electrons on the surface of the conductive resonance layer 6 are excited by the infrared electromagnetic waves, and the electron movement and the incident infrared photoelectric magnetic field mutually excite each other to produce collective resonance movement. Since there is a broken area between the resonance lines, a strong infrared electromagnetic wave resonance will occur at the broken area, greatly enhancing the near-field electric field strength. When the dielectric loss of the material is fixed, the greater the near-field electric field strength, the higher the electromagnetic loss, and ultimately greatly enhancing the absorption of the electromagnetic field; and the conductive resonance layer 6 occupies a small space, has a relatively simple structure, and is very easy to integrate with the related non-cooling infrared pixel structure based on the thermosensitive film material, which greatly reduces the production cost and is conducive to the miniaturization of the device.

[0064] On the basis of the first embodiment, the properties of some epitaxial layers are further improved to obtain the second embodiment, whose structural schematic diagram is the same as the previous one, and includes, from bottom to top, a reflective layer 1, a support layer 2, a thermosensitive film layer 4, a thermosensitive protective layer 5 and a conductive resonance layer 6;

[0065] The reflective layer 1 is spaced apart from the support layer 2, and a resonant cavity 3 is formed between the reflective layer 1 and the support layer 2;

[0066] The conductive resonance layer 6 includes a resonance pattern, the resonance pattern is a pattern composed of resonance lines, and the resonance lines are lines including broken areas;

[0067] The support layer 2 and / or the heat-sensitive protective layer 5 are infrared absorbing layers.

[0068] The difference between this specific embodiment and the above specific embodiment is that, in this specific embodiment, the properties of the support layer 2 and / or the heat-sensitive protective layer 5 are limited, and the remaining structures are the same as those in the above specific embodiment, which will not be elaborated here.

[0069] Please refer to Figure 1, the 1 / 4 wavelength resonant cavity 3 separated by the reflective layer 1 and the support layer 2 is a vacuum cavity, so that the incident infrared energy is focused on the structure composed of the support layer 2, the thermosensitive film layer 4, the thermosensitive protective layer 5 and the conductive resonant layer 6. In this specific embodiment, the support layer 2 and / or the thermosensitive protective layer 5 are further improved to an infrared absorption layer (preferably both are infrared absorption layers), which can further increase the infrared absorption effect, further increase the temperature change amplitude of the infrared detector, thereby improving the sensitivity of the infrared detector and shortening the thermal response.

[0070] Of course, this specific implementation can be further combined with the foregoing. If the infrared detector includes the resonance protection layer 7, the resonance protection layer 7 can also be an infrared absorption layer to further enhance the infrared absorption effect.

[0071] On the basis of the specific implementation mode 1, the resonance pattern is further limited to obtain a specific implementation mode 3, whose structural schematic diagram is as follows: Figure 6 The above-mentioned structure includes, from bottom to top, a reflective layer 1, a support layer 2, a thermosensitive film layer 4, a thermosensitive protective layer 5 and a conductive resonance layer 6;

[0072] The reflective layer 1 is spaced apart from the support layer 2, and a resonant cavity 3 is formed between the reflective layer 1 and the support layer 2;

[0073] The conductive resonance layer 6 includes a resonance pattern, the resonance pattern is a pattern composed of resonance lines, and the resonance lines are lines including broken areas;

[0074] The resonance pattern is a groove pattern opened on the continuous conductive resonance layer 6, and the broken area is a portion of the conductive resonance layer 6 where no groove is opened on the resonance line.

[0075] The difference between this specific embodiment and the above specific embodiment is that, in this specific embodiment, the resonant pattern is defined as a groove opened on the conductive material layer, and accordingly, the broken area is the portion of the conductive resonant layer 6 that is not grooved on the resonant line, that is, the conductive material layer divided by the resonant pattern, and the rest of the structure is the same as the above specific embodiment, and will not be elaborated here.

[0076] What is required for infrared electromagnetic resonance is the size of the pattern of the conductive resonant layer 6. Therefore, regardless of whether the resonant pattern is a pattern formed by deposition of a conductive material (such as Figure 7 ), or a pattern obtained by etching grooves on the conductive material layer (such as Figure 6), both can realize infrared electromagnetic resonance, and the latter is adopted in this specific embodiment. This is because the groove pattern is obtained by etching on the continuous conductive resonance layer 6, the production process is simple, the production efficiency is high, the pattern accuracy is higher, and the finished product yield is also improved accordingly.

[0077] Furthermore, the groove pattern is a groove pattern whose bottom surface exposes the thermosensitive protective layer 5. That is, the resonance pattern is a pattern of hollowing out the conductive resonance layer 6, which can further simplify the production process and improve production efficiency, and is also beneficial to the absorption of infrared rays by other layers below the conductive resonance layer 6.

[0078] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0079] It should be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0080] The infrared detector provided by the utility model is introduced in detail above. This article uses specific examples to illustrate the principle and implementation method of the utility model. The description of the above embodiment is only used to help understand the method and core idea of ​​the utility model. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the utility model, the utility model can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

Claims

1. An infrared detector, characterized in that: It comprises, from bottom to top, a reflective layer (1), a support layer (2), a thermosensitive film layer (4), a thermosensitive protective layer (5) and a conductive resonance layer (6); The reflective layer (1) and the support layer (2) are arranged at an interval, and a resonant cavity (3) is formed between the reflective layer (1) and the support layer (2); The conductive resonance layer (6) comprises a resonance pattern, the resonance pattern is a pattern composed of resonance lines, and the resonance lines are lines including broken areas.

2. The infrared detector according to claim 1, characterized in that: It also includes a resonance protection layer (7); The resonance protection layer (7) covers the conductive resonance layer (6).

3. The infrared detector according to claim 1, characterized in that: The conductive resonance layer (6) comprises a resonance pattern and / or a resonance combination (6'); The resonance combination (6') comprises a plurality of mutually nested resonance patterns.

4. The infrared detector according to claim 3, characterized in that: A plurality of the resonance patterns and / or the resonance combinations (6') are arranged in an array.

5. The infrared detector according to claim 3, characterized in that: The resonance combination (6') comprises at least two nested notched ring resonance patterns; The notched ring resonance pattern is a ring pattern including at least one broken region.

6. The infrared detector according to claim 3, characterized in that: The resonance combination (6') comprises at least two nested rectangular cut resonance patterns; The rectangular cut resonance pattern is a rectangular pattern with at least one broken area; The sides of the rectangular cut resonant pattern nested inside and the rectangular cut resonant pattern nested outside are parallel to each other.

7. The infrared detector according to claim 1, characterized in that: The support layer (2) and / or the heat-sensitive protective layer (5) is an infrared absorbing layer.

8. The infrared detector according to claim 1, characterized in that: The line width of the resonant line ranges from 0.1 micrometers to 10 micrometers, both inclusive.

9. The infrared detector according to any one of claims 1 to 8, characterized in that: The resonance pattern is a groove pattern opened on a continuous conductive resonance layer (6), and the broken area is a portion of the conductive resonance layer (6) that is not grooved on the resonance line.

10. The infrared detector according to claim 9, characterized in that: The groove pattern is a groove pattern whose bottom surface exposes the heat-sensitive protective layer (5).

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