CN116002606A - Infrared thermal radiation detector and manufacturing method thereof - Google Patents
Infrared thermal radiation detector and manufacturing method thereof Download PDFInfo
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- CN116002606A CN116002606A CN202310132870.3A CN202310132870A CN116002606A CN 116002606 A CN116002606 A CN 116002606A CN 202310132870 A CN202310132870 A CN 202310132870A CN 116002606 A CN116002606 A CN 116002606A
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Abstract
The invention discloses an infrared thermal radiation detector and a manufacturing method thereof, relates to the technical field of infrared detection, and aims to solve the problems that an effective detection area of a heat sensitive layer of an existing micro-bridge structure is smaller and a bridge leg mechanical structure is unstable. The infrared thermal radiation detector and the manufacturing method thereof comprise the following steps: the device comprises a substrate, a thermosensitive detection layer and supporting bridge legs, wherein the supporting bridge legs are formed between the substrate and the thermosensitive detection layer, and a resonant cavity is formed between the substrate and the thermosensitive detection layer; the infrared thermal radiation detector further comprises two conductive electrodes connected with the thermosensitive detection layer, and each conductive electrode is respectively contacted with the upper surface of the substrate, the outer surface of the supporting bridge leg, the backlight surface and the side surface of the thermosensitive detection layer. The manufacturing method is used for manufacturing the infrared thermal radiation detector.
Description
Technical Field
The invention relates to an infrared thermal radiation detector, in particular to an infrared thermal radiation detector and a manufacturing method thereof.
Background
The infrared thermal radiation detector type uncooled infrared detector is the subject of vigorous research and development for decades, and has the advantages of portability, excellent performance, low cost and the like, and has wide military and civil prospects.
At present, most of infrared thermal radiation detectors adopt a traditional single-sacrificial layer micro-bridge structure, the heat-sensitive effective detection area of the single-sacrificial layer micro-bridge structure is smaller, and the bridge leg mechanical structure is unstable. In recent years, infrared thermal radiation detectors of a multilayer structure have been proposed so that these problems are alleviated, but the manufacturing process of the multilayer structure is complicated and the mechanical properties cannot be effectively improved.
Disclosure of Invention
The invention provides an infrared thermal radiation detector and a manufacturing method thereof, which not only can efficiently absorb infrared energy, but also can improve the mechanical property of bridge legs, thereby ensuring that the infrared thermal radiation detector has good structural stability and infrared absorption property.
In order to achieve the above object, the present invention provides an infrared thermal radiation detector including:
the device comprises a substrate, a thermosensitive detection layer and supporting bridge legs, wherein the supporting bridge legs are formed between the substrate and the thermosensitive detection layer, and a resonant cavity is formed between the substrate and the thermosensitive detection layer;
the infrared thermal radiation detector further comprises two conductive electrodes, wherein the substrate is connected with the thermosensitive detection layer, and each conductive electrode is respectively contacted with the upper surface of the substrate, the outer surface of the supporting bridge leg, the backlight surface and the side surface of the thermosensitive detection layer.
Compared with the prior art, in the infrared thermal radiation detector provided by the invention, the supporting bridge legs are formed between the substrate and the thermosensitive detection layer, so that the supporting bridge legs do not occupy the absorption surface of the thermosensitive detection layer, the infrared absorption area of micro-measurement radiation heat is increased, and the supporting bridge legs can have a good supporting effect on the thermosensitive detection layer, so that the infrared thermal radiation detector is more stable. On the basis, the infrared thermal radiation detector provided by the invention further comprises two conductive electrodes connected with the thermosensitive detection layer, and each conductive electrode is respectively contacted with the upper surface of the substrate, the outer surface of the supporting bridge leg and the backlight surface and the side surface of the thermosensitive detection layer, so that when the infrared thermal radiation detector is used for infrared light detection, the conductive electrodes can be used for directly transmitting electric signals.
The invention also provides a manufacturing method of the infrared thermal radiation detector, which comprises the following steps:
providing a substrate;
forming a support bridge leg over the substrate;
forming two first conductive segments over the substrate;
two second conductive sections are formed on the outer surface of the supporting bridge leg, and the two first conductive sections are respectively connected with the two corresponding second conductive sections;
forming a sacrificial layer over the substrate, the sacrificial layer having a thickness that is the same as a thickness of the support bridge leg;
forming two third conductive segments on the surface of the sacrificial layer, which is away from the substrate, wherein the two third conductive segments are respectively connected with the two corresponding second conductive segments;
forming a thermosensitive detection layer and two fourth conductive segments above the sacrificial layer and the two third conductive segments, wherein the two fourth conductive segments are respectively connected with the corresponding two third conductive segments;
and removing the sacrificial layer to form a resonant cavity between the substrate and the thermosensitive detection layer.
Compared with the prior art, the manufacturing method of the infrared thermal radiation detector has the advantages that the manufacturing method of the infrared thermal radiation detector has the same advantages as those of the infrared thermal radiation detector provided by the technical scheme, and details are omitted herein.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and do not constitute a limitation on the invention. In the drawings:
FIG. 1 shows a schematic structure of an infrared thermal radiation detector with a single-layer micro-bridge structure in the prior art;
FIG. 2 shows a schematic diagram of a prior art dual layer structure of an infrared thermal radiation detector;
FIG. 3A is a schematic diagram showing a cross-sectional structure of an infrared thermal radiation detector according to an embodiment of the present invention;
3B-3D show schematic structural diagrams of a single-layer microbridge infrared thermal radiation detector provided by the embodiment of the invention;
FIGS. 4A-4N are schematic diagrams illustrating the structural states of an infrared thermal radiation detector at different stages of fabrication according to an exemplary embodiment of the present invention;
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. The meaning of "a number" is one or more than one unless specifically defined otherwise.
In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc., are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; the connection can be mechanical connection or connection; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
The infrared thermal radiation detector is a resistance type thermal sensor, and the working principle is that the infrared radiation emitted by a target object is absorbed, when the temperature change of a thermosensitive material is caused, the resistance of the thermosensitive material is also changed, and corresponding electrical signals are generated under the action of externally applied bias and output, and then the image information is restored.
Fig. 1 shows a schematic structural diagram of an infrared thermal radiation detector with a single-layer micro-bridge structure in the prior art. As shown in fig. 1, the infrared thermal radiation detector 100 of a single-layer structure includes a substrate 101 and a microbridge structure provided over the substrate 101.
As shown in fig. 1, the deck of the microbridge structure has a thermally sensitive detection layer 102 and two bridge legs 103 extending onto a substrate 101. The heat sensitive detection layer 102 is a picture element of the infrared thermal radiation detector 100.
As shown in fig. 1, when the infrared thermal radiation detector 100 works, the detected object releases infrared light, the heat sensitive detection layer 102 absorbs infrared light, and then the resistance value of the heat sensitive detection layer 102 is changed, and the heat sensitive detection layer 102 has a sandwich structure and comprises two infrared absorption layers and a heat sensitive layer located between the two infrared absorption layers. The infrared thermal radiation detector 100 has two bridge legs 103 formed on a substrate, the bridge legs 103 being composed of SiO-coated material 2 And supporting the wrapped aluminum column. If the infrared is given by a lead wireThe thermal radiation detector 100 applies a bias voltage, and generates a corresponding electrical signal output under the action of the bias voltage, so that an external processing circuit can detect weak current change caused by corresponding resistance change, thereby achieving the purpose of infrared detection.
When the infrared absorption layer of the thermosensitive detection layer absorbs infrared radiation, the absorbed infrared energy enables the bridge deck temperature of the micro-bridge structure to rise, and the resistance of the thermosensitive layer is changed. At this time, a bias voltage is applied to the bolometer, so that a corresponding voltage signal output can be generated. In a conventional single-layer microbridge structure, the existence of the bridge legs in the single-layer structure occupies the effective heat-sensitive detection area in the center of the pixel, and the mismatch of the length and width of the bridge legs and the heat-sensitive effective detection area affects the performance of the device, so that the detection efficiency is reduced.
Fig. 2 shows a schematic diagram of a prior art double layer structure of an infrared thermal radiation detector. As shown in fig. 2, the bilayer structure includes a substrate and a microbridge structure disposed over the substrate.
As shown in fig. 2, the infrared thermal radiation detector 200 of the double-layer microbridge structure has a heat sensitive detection layer 202, two double-layer S-shaped hidden bridge legs 201 formed between a Si substrate 204 and the heat sensitive detection layer 202. The heat sensitive detection layer 202 is an infrared thermal radiation detector pixel, which is a sandwich structure and comprises an infrared absorption layer, a heat sensitive layer and a passivation layer. The absorption film system of the double-layer S-shaped hidden bridge leg 201 infrared thermal radiation detector 200 can be as follows from top to bottom: si (Si) 3 N 4 Absorption layer, VO X Thermally sensitive film, si 3 N 4 Passivation layer, upper resonant cavity, si 3 N 4 Support layer 203 (i.e., thermal support bridge leg), niCr electrode layer, si 3 N 4 A support layer 203, a lower resonator, and a Si substrate 204. When the infrared thermal radiation detector 200 works, the detected object releases infrared light, and the heat sensitive detection layer 202 absorbs infrared light, so as to change the resistance value of the heat sensitive detection layer 202, wherein as shown in fig. 2, the infrared thermal radiation detector 200 has four bridge legs, so that the heat sensitive detection layer 202 and Si 3 N 4 The deck on which the support layer 203 is located is completely separated so that it no longer affects each other. If the wire is led to theThe infrared thermal radiation detector 200 applies a bias voltage, and generates corresponding electrical signal output under the action of the bias voltage, so that an external processing circuit can detect weak current change caused by corresponding resistance change, and the purpose of infrared detection is achieved.
The design key point of the double-layer micro-bridge structure is to completely separate the bridge deck where the optical absorption material is located from the bridge deck where the bridge legs are located, so that the bridge decks are not mutually influenced. In the traditional double-layer microbridge structure, although the thermosensitive detection layer has a larger detection area, the double-layer structure has complex manufacturing process, the difficulty of process realization and the cost are improved, and the mechanical property of the middle electrode layer is poor and is easy to bend and break. Moreover, a substantial increase in bridge leg length has a negative impact on the stability of the device.
Based on the above problems, the embodiment of the invention provides an infrared thermal radiation detector and a manufacturing method thereof, and the infrared thermal radiation detector provided by the embodiment of the invention improves the stability of a device structure, increases the area of an infrared absorption layer, and obviously enhances the sensitivity and the response rate of the device. It should be appreciated that the type of infrared thermal radiation detector may be, but is not limited to, a microwave infrared detector, a passive infrared/microwave infrared detector, a vibratory infrared detector, an ultrasonic infrared detector, a laser infrared detector.
Fig. 3A shows a schematic cross-sectional structure of three infrared thermal radiation detectors according to an embodiment of the present invention. As shown in fig. 3A, an infrared thermal radiation detector 300 provided in an embodiment of the present invention includes: a substrate 301, a thermally sensitive detection layer 303 and a support bridge leg 302.
The substrate may be any of a variety of possible substrates, for example, the substrate may be a semiconductor substrate, for example: silicon substrates, silicon nitride substrates, silicon carbide substrates, polysilicon substrates, and the like, may also be glass substrates, flexible substrates, such as polyimide substrates, and the like.
Fig. 3B shows a schematic structural diagram of a single-layer microbridge infrared thermal radiation detector according to an embodiment of the present invention. Fig. 3C shows a schematic diagram of a cross-sectional structure of a bridge leg of a single-layer microbridge infrared thermal radiation detector according to an embodiment of the present invention, and fig. 3D shows a schematic diagram of a cross-sectional structure of a conductive electrode in a single-layer microbridge infrared thermal radiation detector according to an embodiment of the present invention. As shown in fig. 3B to 3D, the supporting bridge legs 302 are formed between the substrate 301 and the thermosensitive detecting layer 303, and the existence of the supporting bridge legs 302 forms a resonant cavity between the substrate 301 and the thermosensitive detecting layer 303. When the infrared light passes through the thermosensitive detection layer 303 and enters the resonant cavity, the infrared light is reflected on the surface of the substrate 301 and the side surface of the supporting bridge leg 302, and is absorbed by the thermosensitive detection layer 303 again, so that the absorption rate of the infrared light released by the measured object is improved.
As shown in fig. 3B to 3D, the above-mentioned infrared thermal radiation detector 300 further includes two conductive electrodes 305 connected to the heat sensitive detection layer 303, and each conductive electrode 305 is respectively in contact with the upper surface of the substrate 301, the outer surface of the support bridge leg 302, and the backlight surface and side surface of the heat sensitive detection layer 303. In the process of absorbing infrared light by the thermosensitive detecting layer 303, the temperature of the thermosensitive detecting layer 303 is changed, and thus the resistance value of the thermosensitive layer 3032 is changed. Based on this, when a bias voltage is applied to the thermosensitive detecting layer 303, a corresponding electrical signal output is generated under the action of the bias voltage, so that an external processing circuit can detect a weak current change caused by a corresponding resistance change, thereby achieving the purpose of infrared detection.
As shown in fig. 3A to 3D, the infrared thermal radiation detector 300 has only one support bridge leg 302, the support bridge leg 302 is formed between the substrate 301 and the heat sensitive detection layer 303, and the cross section of the support bridge leg 302 is gradually reduced along the height increasing direction of the support bridge leg 302, based on this, the support bridge leg 302 may have a pyramid structure and various cone structures, the support bridge leg 302 under the structure has better mechanical properties, and the bottom area of the support bridge leg 302 may be 4/5 of the surface area of the upper surface of the substrate 301, at this time, the support effect on the heat sensitive detection layer 303 is best.
In one example, the upper surface of the substrate may be a 50 μm by 50 μm rectangle, the bottom surface of the support bridge may be a 40 μm circle in diameter, and the thickness may be 2.0 μm, at which point the support bridge is approximately 4/5 of the upper surface of the substrate. It should be understood that the support bridge leg employed in the present invention is of a tapered configuration.
As shown in fig. 3A, the supporting bridge leg 302 may include a supporting layer 3021 and a heat insulating layer 3022, where the supporting layer 3021 is used as a main supporting layer, so that the supporting bridge leg 302 has a better mechanical property, and the supporting layer 3021 may be made of a material with a poor thermal conductivity, so as to ensure that the heat absorbed by the heat sensitive detecting layer 303 is not conducted out by the supporting layer 3021 as much as possible. On the basis, a heat insulating layer 3022 can be formed on the surface of the supporting layer 3021, and because the temperature change of the heat sensitive detection layer 303 before and after infrared light irradiation is relatively large, the heat insulating layer 3022 can avoid the problem that the resistance change error of the heat sensitive detection layer 303 is relatively large because heat is led out by the supporting layer 3021, thereby reducing the problem of low infrared detection capability and detecting an electric signal more sensitively. And the outer surface of the supporting bridge leg 302 can reflect the infrared light in the resonant cavity to the thermosensitive detection layer 303, so that the absorption rate of the infrared light released by the detected object is enhanced, and the detection effect is more accurate.
In one example, a support layer is formed on an upper surface of the substrate, and a thermal insulation layer is formed on the upper surface of the support layer. Because the heat sensitive detection layer is formed on the heat insulating layer, and the heat insulating layer is formed on the supporting layer, based on the heat insulating layer and the supporting layer, the heat insulating layer and the supporting layer form an insulating structure with double film layers, the energy loss of the heat sensitive detection layer caused by the heat conductivity of the supporting bridge leg is avoided, the problem that the detection value and the actual value are greatly different is caused, and the detection of the heat sensitive detection layer is more accurate.
In one example, the support layer may be silicon nitride, which has poor thermal conductivity and is insulating; the heat insulating layer may be a heat insulating material such as a paralene or aerogel.
In one example, the support layer thickness may be between 1 μm and 1.5 μm and the thermal insulation layer thickness may be between 700nm and 1 μm.
As shown in fig. 3A to 3D, each of the conductive electrodes 305 includes a first conductive segment 3051, a second conductive segment 3052, a third conductive segment 3053, and a fourth conductive segment 3054, the first conductive segment 3051 is formed on the upper surface of the substrate 301, the second conductive segment 3052 is formed on the outer surface of the supporting bridge leg 302, the third conductive segment 3053 is formed on the backlight surface of the heat sensitive detection layer 303, the fourth conductive segment 3054 is formed on the side surface of the heat sensitive detection layer 303, and the conductive electrode 305 can derive an electrical signal detected by the heat sensitive detection layer 303. In addition, the conductive electrode 305 is not entirely covered on the upper surface of the substrate 301, the outer surface of the supporting bridge leg 302, the backlight surface and the side surface of the thermosensitive detecting layer 303, but is formed locally, so that the heat conduction capability of the conductive electrode 305 can be reduced by controlling the thickness and the width of the conductive electrode 305, and the energy loss of the thermosensitive detecting layer 303 due to the good heat conductivity of the conductive electrode 305 is avoided, thereby leading to a larger difference between the detected value and the actual value.
In one example, the first conductive segment and the second conductive segment may be in an integrated structure, and an included angle between the first conductive segment and the second conductive segment is greater than 90 and less than 180, so that the transition between the first conductive segment and the second conductive segment is better and is not easy to break due to the integrated structure, and signal transmission is more stable.
In one example, the first conductive segment is connected to the second conductive segment, the second conductive segment is connected to the third conductive segment, and the third conductive segment is connected to the fourth conductive segment.
In one example, the conductive electrode may be any conductive metal, such as gold, silver, copper, or the like.
In one example, when the conductive metal is selected as the electrode material, the electrode is unstable when the thickness of the conductive metal film is too small, and the heat loss of the infrared thermal radiation detector is extremely aggravated when the thickness of the conductive metal film is too large, so that the thickness of the conductive electrode can be controlled to be 5 nm-50 nm, and the width can be set according to the actual situation, at this time, not only the good conductivity of the conductive electrode can be ensured, but also the heat loss of the infrared thermal radiation detector can be reduced. The width of the conductive electrode can be set to be 1 μm, and the conductive electrode has heat conductivity, so that the thickness of the film of the conductive electrode is made as thin as possible, thereby reducing the heat transmission of the conductive electrode, and reducing the heat loss caused by the conductive electrode as far as possible under the condition of stable conductive performance of the electrode. The supporting bridge leg structure provided by the invention is not only convenient for depositing the electrode, but also can deposit the metal electrode with nano-scale thickness, so that not only is the good conductivity of the metal electrode ensured, but also the heat contained in the thermosensitive detection layer can be prevented from being led out by the metal electrode with nano-scale thickness, and on the basis of the heat conduction, the measurement accuracy of the infrared thermal radiation detector can be ensured, the material can be saved, and the detection effect is more accurate.
As shown in fig. 3A, the infrared thermal radiation detector 300 further includes a first protection layer 306, where the first protection layer 306 is located between the third conductive segments 3053 included in the two conductive electrodes 305, the first protection layer 306 is also located between the supporting bridge leg 302 and the heat sensitive detection layer 303, and the first protection layer 306 makes a good transition at the included angle between the second conductive segments 3052 and the third conductive segments 3053, so as to avoid easy breakage between the second conductive segments 3052 and the third conductive segments 3053 due to too small included angle between the second conductive segments 3052 and the third conductive segments 3053.
In one example, the thickness of the first protective layer may be consistent with the thickness of the third conductive segment, and the width may be determined according to the actual situation.
As shown in fig. 3A, the heat sensitive detection layer 303 includes a second protection layer 3031, a heat sensitive layer 3032 and a third protection layer 3033 which are stacked, and the second protection layer 3031 and the third protection layer 3033 are used for absorbing infrared light released by an object to be measured and protecting the heat sensitive layer 3032; alternatively, the heat sensitive layer 3032 may be vanadium oxide, and when the temperature of the heat sensitive detection layer 303 changes due to infrared light absorption, the resistance value of the heat sensitive layer 3032 changes. Based on this, when a bias voltage is applied to the thermosensitive detecting layer 303, a corresponding electric signal is generated. It should be appreciated that the third protective layer 3033 forms a sandwich structure with the heat sensitive layer 3032 and the second protective layer 3031, so that the third protective layer 3033 and the second protective layer 3031 better protect the heat sensitive layer 3032.
In an example, the second protection layer and the third protection layer may be silicon nitride.
As shown in fig. 3A, the infrared thermal radiation detector 300 further includes two contact electrodes 307, the heat sensitive layer 3032 is located between the two contact electrodes 307, the second protective layer 3031 is located between the two fourth conductive segments 3054, and each conductive electrode 305 is connected to the heat sensitive layer 3032 by the corresponding contact electrode 307.
In one example, as shown in fig. 3A, two contact electrodes 307 are also in contact with the heat sensitive layer 3032, two fourth conductive segments 3054 are also in contact with the second protective layer 3031, and two contact electrodes 307 are respectively located above the two fourth conductive segments 3054, and the two contact electrodes 307 are respectively connected to the respective two fourth conductive segments 3054. Based on this, when the resistance value of the heat sensitive layer 3032 changes, the external processing circuit can detect a weak current change caused by the corresponding resistance change through the conductive electrode 305. It should be understood that the location of the conductive electrode 305 is not limited herein, but must be connected to the contact electrode 307.
In an example, the contact electrode may be a metal material, for example, a high temperature resistant metal such as tungsten, and the thickness may be controlled between 5nm and 50 nm.
As shown in fig. 3A, the infrared thermal radiation detector 300 provided by the present invention further includes an insulating reflective layer 304, an infrared enhancement layer 308, and an infrared absorption layer 309, where the infrared enhancement layer 308 is located on a light-facing surface of the heat sensitive detection layer 303 and is used for enhancing infrared absorption of the heat sensitive detection layer 303, the insulating reflective layer 304 is located on an upper surface of the substrate 301, the infrared absorption layer 309 is located on the light-facing surface of the infrared enhancement layer 308 and is used for protecting the infrared enhancement layer 308 and absorbing infrared light, and a three-layer film structure is formed with the infrared enhancement layer 308 and the third protection layer 3033, so as to better absorb infrared energy. It should be appreciated that the insulating reflective layer 304 is effective to prevent the conductive electrode 305 from contacting the conductive substrate 301 to generate leakage.
In one example, the infrared enhancement layer can be any material that enhances infrared absorption, such as a nickel-chromium material, graphene, or the like.
In one example, the infrared absorbing layer may be silicon nitride.
In one example, when the infrared enhancement layer and the infrared absorption layer are made of the same material, at least one of two-dimensional graphene, two-dimensional molybdenum disulfide and two-dimensional transition metal carbide can be directly selected as the infrared enhancement layer to be formed on the surface of the heat-sensitive detection layer.
Optionally, as shown in fig. 3C, an insulating reflective layer 304 is formed on the surface of the substrate 301, where the insulating reflective layer 304 and the backlight of the thermosensitive detecting layer 303 form a resonant cavity, when infrared light passes through the thermosensitive detecting layer 303 and enters the resonant cavity, the light wave is reflected by the insulating reflective layer 304 and the side surface of the supporting bridge leg 302 to the second protective layer 3031 of the thermosensitive detecting layer 303, and the second protective layer 3031 absorbs infrared energy reflected by the resonant cavity to perform secondary absorption, and the second protective layer 3031 may also protect the thermosensitive layer 3032.
Fig. 4A to 4N are schematic structural views of an infrared thermal radiation detector at different manufacturing stages according to an exemplary embodiment of the present invention. As shown in fig. 4A to 4N, the method for manufacturing the infrared thermal radiation detector 400 according to the embodiment of the invention includes:
as shown in fig. 4A, a substrate 401 is provided, for example, the substrate 401 is prepared and cleaned, and the material of the substrate 401 may be referred to as above, which is not illustrated.
As shown in fig. 4B to 4D, forming a supporting bridge leg 402 above a substrate 401 may specifically include:
first, as shown in fig. 4B, after the substrate 401 is formed, a support layer material 40211 such as silicon nitride or other material which has low thermal conductivity and is insulating is deposited by CVD or the like.
Next, as shown in fig. 4C, a deposited insulating material 40221, such as a insulating material of Paralene, aerogel, or the like, is formed on the surface of the support layer material 40211 facing away from the substrate 401.
Finally, as shown in fig. 4D, photoresist is coated over the thermal insulation material 40221 to form a photoresist layer, the support layer material 40211 and the thermal insulation material 40221 are etched by using a gray scale etching method to form a support layer 4021 and a thermal insulation layer 4022, the support layer material 40211 forms the support layer 4021 and the thermal insulation reflective layer 403 after being etched, the thermal insulation material 40221 forms the thermal insulation layer 4022 after being etched, and the support bridge leg 402 structure comprises the support layer 4021 and the thermal insulation layer 4022. The substrate 401 of the invention adopts the specification size of 50 μm×50 μm, the conical structure is a circular shape with the bottom diameter of 40 μm and the thickness of 2.0 μm, wherein the thickness of the supporting layer 4021 can be 1 μm-1.5 μm, and the thickness of the heat insulating layer 4022 is 700 nm-1 μm. It should be appreciated that the support bridge legs 402 may be pyramid structures or various cone structures, and that a double layer glue etching process, a microlens etching process, etc. may be selected in addition to the gray scale etching method. Here, the support layer material 40211 may be silicon nitride, which has poor heat conductive property and is insulating; the heat insulating material 40221 may be a heat insulating material such as a paralene or aerogel.
As shown in fig. 4E, two first conductive segments 4051 are formed over the substrate 401; two second conductive segments 4052 are formed on the outer surface of the support bridge leg 402, and the two first conductive segments 4051 are respectively connected with the corresponding two second conductive segments 4052; specifically, photoresist is coated on the surface of the insulating reflective layer 403 facing away from the substrate 401 and the surface of the supporting bridge leg 402, so as to deposit a conductive material, and the optional conductive material may be any conductive metal, such as gold, silver, copper, and the like. Here, the first conductive segment 4051 and the second conductive segment 4052 may be formed in a unified film forming process, i.e. an integrated structure, so that the transition between the first conductive segment 4051 and the second conductive segment 4052 is better and is not easy to break, and the signal transmission is more stable.
As shown in fig. 4F, a sacrificial layer 404 may be formed over the substrate 401. It should be appreciated that the thickness of the sacrificial layer 404 is the same as the thickness of the support bridge leg 402, and the material of the sacrificial layer 404 may be silicon dioxide, polyimide, or the like.
As shown in fig. 4G, two third conductive segments 4053 are formed on the surface of the sacrificial layer 404 facing away from the substrate 401, and the two second conductive segments 4052 are respectively connected to the corresponding two third conductive segments 4053; specifically, a conductive material is deposited on the surface of the sacrificial layer 404, and then a photoresist is coated, and the third conductive segment 4053 is obtained after photolithography, where the optional conductive material may be any conductive metal, such as gold, silver, copper, and the like.
As shown in fig. 4G, a thermosensitive detecting layer and two fourth conductive segments 4054 are formed over the sacrificial layer 404 and the two third conductive segments 4053. Wherein, two fourth conductive segments 4054 are formed at two ends of the sacrificial layer 404, and the two fourth conductive segments 4054 are respectively connected with the two third conductive segments 4053. Specifically, a conductive material may be deposited on the surface of the sacrificial layer 404, and then a photoresist may be coated, and two fourth conductive segments 4054 may be formed after photolithography. The optional conductive material may be any conductive metal such as gold, silver, copper, and the like. It should be appreciated that the conductive electrode 405 includes a first conductive segment 4051, a second conductive segment 4052, a third conductive segment 4053, and a fourth conductive segment 4054, and the conductive electrode 405 may have a width of 1 μm and a thickness of between 5nm and 50nm, as the case may be.
As shown in fig. 4h to 4k, a heat sensitive detection layer 408 is formed above the sacrificial layer 404, specifically, including sequentially forming a second protective layer 4081, a heat sensitive layer 4082, and a third protective layer 4083, which are stacked, on a surface of the third conductive segment 4053 facing away from the substrate 401, and forming two contact electrodes 406.
First, as shown in fig. 4H, a second protective layer 4081 material is deposited as a second protective layer 4081 on the surface of the third conductive segment 4053 facing away from the substrate 401. For example: a second protective layer 4081 of material, such as silicon nitride, is deposited on the surface of the third conductive segment 4053 facing away from the substrate 401 by CVD or the like, and the second protective layer 4081 is located between the two fourth conductive segments 4054, the second protective layer 4081 is in contact with the two fourth conductive segments 4054, and the first protective layer 407 is located between the third conductive segments 4053, where the thickness of the first protective layer 407 may be consistent with the thickness of the third conductive segment 4053, and the width may be determined according to the practical situation.
Next, as shown in fig. 4I, after the two fourth conductive segments 4054 are formed on the surface of the sacrificial layer 404 facing away from the substrate, the method for manufacturing the infrared thermal radiation detector 400 further includes forming two contact electrodes 406 on the surface of the fourth conductive segment 4054 facing away from the substrate 401; specifically, a conductive material may be deposited on the surfaces of the two fourth conductive segments 4054 and the second protective layer 4081 facing away from the substrate 401, and then a photoresist may be coated, and two contact electrodes 406 may be formed on the upper surfaces of the fourth conductive segments 4054 after photolithography. Here, the two contact electrodes 406 may be in the same size as the two fourth conductive segments 4054, and the thickness of the two contact electrodes 406 may be between 5nm and 50nm, and the optional conductive material may be any conductive metal, such as gold, silver, copper, etc., as the case may be. Next, as shown in fig. 4J, a heat sensitive layer 4082 is formed on the surface of the second protective layer 4081 facing away from the substrate 401. It should be appreciated that here, the heat sensitive layer 4082 is located between the two contact electrodes 406 and is in contact with the two contact electrodes 406. For example: the heat sensitive material is deposited by CVD or the like to form the heat sensitive layer 4082, and the heat sensitive layer 4082 in the embodiment of the present invention is vanadium oxide.
Finally, as shown in fig. 4K, a third protective layer 4083 is deposited on the heat sensitive layer 4082 and on the surface of the two contact electrodes 406 facing away from the substrate 401. For example: a third protective layer 4083 material, such as silicon nitride, is deposited by CVD or the like on the surface of the third conductive segment 4053 facing away from the substrate 401.
As shown in fig. 4l to 4n, after forming the thermal sensitive detection layer 408 above the sacrificial layer 404, the method further includes:
as shown in fig. 4L, an infrared ray enhancement layer 409 is formed on the light-facing surface of the heat sensitive detection layer 408. For example, the infrared absorbing material, which may be nickel chromium, graphene, or the like, is deposited by CVD or the like to form the infrared enhancing layer 409.
As shown in fig. 4M, an infrared absorption layer 4010 is formed on the light-facing surface of the infrared enhancement layer 409. For example, an infrared absorbing layer 4010 is obtained by depositing a silicon nitride material on the surface of infrared enhancing layer 409 facing away from substrate 401.
As shown in fig. 4N, the sacrificial layer 404 is removed so that a resonant cavity is formed between the substrate 401 and the heat sensitive detection layer 408.
In the above description, technical details of patterning, etching, and the like of each layer are not described in detail. Those skilled in the art will appreciate that layers, regions, etc. of the desired shape may be formed by a variety of techniques. In addition, to form the same structure, those skilled in the art can also devise methods that are not exactly the same as those described above. In addition, although the embodiments are described above separately, this does not mean that the measures in the embodiments cannot be used advantageously in combination.
The embodiments of the present invention are described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be made by those skilled in the art without departing from the scope of the invention, and such alternatives and modifications are intended to fall within the scope of the invention.
Claims (12)
1. An infrared thermal radiation detector, comprising: the device comprises a substrate, a thermosensitive detection layer and supporting bridge legs, wherein the supporting bridge legs are formed between the substrate and the thermosensitive detection layer, and a resonant cavity is formed between the substrate and the thermosensitive detection layer;
the infrared thermal radiation detector further comprises two conductive electrodes, wherein the substrate is connected with the thermosensitive detection layer, and each conductive electrode is respectively contacted with the upper surface of the substrate, the outer surface of the supporting bridge leg, the backlight surface and the side surface of the thermosensitive detection layer.
2. The infrared thermal radiation detector as defined in claim 1, wherein the cross section of the support bridge leg is gradually reduced along the direction of increasing height of the support bridge leg.
3. The infrared radiation detector as defined in claim 1, wherein the support bridge leg bottom area is 4/5 of the substrate upper surface area.
4. The infrared thermal radiation detector of claim 1, wherein the support bridge leg comprises a support layer and a thermal insulation layer;
the support layer is formed on the substrate, the heat insulating layer is formed on the support layer, and the heat sensitive detection layer is formed on the heat insulating layer.
5. The infrared thermal radiation detector of claim 1, wherein each of the conductive electrodes comprises a first conductive segment formed on an upper surface of the substrate, a second conductive segment formed on an outer surface of the support bridge leg, a third conductive segment formed on a backlight surface of the heat sensitive detection layer, and a fourth conductive segment formed on a side surface of the heat sensitive detection layer;
the first conductive section and the second conductive section are of an integrated structure, the second conductive section is connected with the third conductive section, the third conductive section is connected with the fourth conductive section, and an included angle between the first conductive section and the second conductive section is larger than 90 degrees and smaller than 180 degrees.
6. The infrared thermal radiation detector as defined in claim 5, further comprising a first protective layer between the two third conductive segments, the first protective layer further being between the support bridge leg and the heat sensitive detection layer.
7. The infrared thermal radiation detector as claimed in any one of claims 1 to 6, wherein the heat sensitive detection layer comprises a second protective layer, a heat sensitive layer and a third protective layer which are laminated;
the infrared thermal radiation detector further comprises two contact electrodes, the heat sensitive layer is positioned between the two contact electrodes, the second protective layer is positioned between the two fourth conductive sections, and each conductive electrode is connected with the heat sensitive detection layer through the corresponding contact electrode;
the two contact electrodes are in contact with the heat sensitive layer, the two fourth conductive sections are in contact with the second protective layer, the two contact electrodes are respectively positioned on the two fourth conductive sections, and the two contact electrodes are respectively in contact with the two fourth conductive sections.
8. The infrared thermal radiation detector as defined in claim 7, further comprising an insulating reflective layer, an infrared enhancement layer, and an infrared absorption layer;
the insulation reflecting layer is positioned on the upper surface of the substrate, the infrared enhancement layer is positioned on the light-facing surface of the thermosensitive detection layer, and the infrared absorption layer is positioned on the light-facing surface of the infrared enhancement layer.
9. A method of fabricating an infrared thermal radiation detector, comprising:
providing a substrate;
forming a support bridge leg over the substrate;
forming two first conductive segments over the substrate;
two second conductive sections are formed on the outer surface of the supporting bridge leg, and the two first conductive sections are respectively connected with the two corresponding second conductive sections;
forming a sacrificial layer over the substrate, the sacrificial layer having a thickness that is the same as a thickness of the support bridge leg;
forming two third conductive segments on the surface of the sacrificial layer, which is away from the substrate, wherein the two third conductive segments are respectively connected with the two corresponding second conductive segments;
forming a thermosensitive detection layer and two fourth conductive segments above the sacrificial layer and the two third conductive segments, wherein the two fourth conductive segments are respectively connected with the corresponding two third conductive segments;
and removing the sacrificial layer to form a resonant cavity between the substrate and the thermosensitive detection layer.
10. The method of fabricating an infrared thermal radiation detector as defined in claim 9, wherein after providing a substrate, the method further comprises:
forming an insulating reflective layer over the substrate;
the forming a support bridge leg over the substrate, comprising:
a support layer is formed over the substrate,
and forming a heat insulation layer on the surface of the supporting layer, which is away from the substrate.
11. The method for manufacturing an infrared thermal radiation detector as defined in claim 9, wherein after the two fourth conductive segments are formed on the surface of the sacrificial layer facing away from the substrate, the method for manufacturing an infrared thermal radiation detector further comprises:
forming a first protective layer on the surface of the heat insulating layer;
forming two contact electrodes on the surface of the fourth conductive segment facing away from the substrate;
the forming a heat sensitive detection layer over the sacrificial layer includes:
and sequentially forming a second protective layer, a heat-sensitive layer and a third protective layer which are stacked on the surface of the third conductive segment, which is away from the substrate, wherein two contact electrodes are contacted with the heat-sensitive layer, and two fourth conductive segments are contacted with the second protective layer.
12. The method of fabricating an infrared thermal radiation detector as defined in claim 9, wherein after forming a thermally sensitive detection layer over the sacrificial layer, the method further comprises:
an infrared enhancement layer is formed on the light-facing surface of the thermosensitive detection layer,
and forming an infrared absorption layer on the light-facing surface of the infrared enhancement layer.
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