CN202420685U - Optical read-out heat-mechanical infrared detector structure - Google Patents

Abstract

The utility model discloses an optical readout thermal-mechanical infrared detector structure. The optical readout thermal-mechanical infrared detector structure includes several pixel units distributed in an array, and each pixel unit includes: a substrate, Support layer, infrared absorbing layer, reflective sheet and bi-material cantilever beam. The infrared detector structure not only inherits the advantages of the above-mentioned FPA with a substrate and the fully hollow FPA, but also overcomes their shortcomings. Compared with the FPA with substrate structure, this structure improves the infrared absorption efficiency, and improves the temperature uniformity of the film area compared with the fully hollow FPA, so that each pixel can work independently, and the thermal response rate is improved. On the support layer, there is no need for an additional support frame, which improves the duty cycle; in addition, the design of the upper and lower superimposed deformed cantilever beam structure not only improves the temperature response sensitivity, but also improves the optical fill factor, which is more conducive to the pixel to a smaller size direction development.

Description

Optical Readout Thermal-Mechanical Infrared Detector Structure

technical field

The utility model relates to an optical readout thermal-mechanical infrared detector structure. the

Background technique

Infrared technology is widely used in various industries such as industry, agriculture, medical treatment, and science. Infrared imaging, infrared temperature measurement, infrared physiotherapy, infrared detection, infrared alarm, infrared remote sensing, and infrared heating are advanced technologies that various industries are competing to choose. In the military, infrared imaging, infrared reconnaissance, infrared tracking, infrared guidance, infrared early warning, infrared confrontation, etc. are indispensable tactical and strategic means in modern and future warfare. the

Infrared detectors are used to convert invisible infrared radiation into visible images. According to different detection principles, traditional detectors can be divided into two categories: photoelectric infrared detectors and thermal infrared detectors. Photoelectric infrared detectors have the characteristics of fast response time and low NETD, and are widely used in military affairs. However, due to the need to separate photoelectrons and thermal electrons during its work, refrigeration (working in a liquid nitrogen (77K) environment) equipment is required, resulting in large volume, high power consumption, and high price of this kind of infrared detector, which limits its application to civilian use. direction development. In recent years, uncooled infrared detectors developed by utilizing the characteristic of infrared radiation with significant thermal effect have been gradually commercialized. Typical infrared detectors include thermal resistance, thermopile and pyroelectric infrared detectors. This kind of detector is flexible to manufacture, does not need refrigeration, has low power consumption and low cost, and has been gradually applied in various fields. However, this kind of detectors all adopt the way of electric readout, because the detection signal is small, so it puts forward high requirements for the design of the readout circuit, and also increases the difficulty of the manufacturing process of the whole chip. In addition, the heat generated by the power consumption of the readout circuit also affects the response of the detector's sensitive elements. With the development of MEMS technology, opto-mechanical uncooled infrared detectors have become a research hotspot in recent years. This type of detector has flexible design, simple manufacturing process, and non-contact optical readout method for signal readout, which greatly reduces power consumption. At the same time, it is theoretically predicted that the NETD of this type of detector can reach 5mK, which has a very broad application prospect. Considering the adiabatic structure design, this type of detector can usually be divided into infrared FPA (focal plane array) with substrate structure based on sacrificial layer release technology, and FPA structure without substrate and fully hollowed out. The FPA with a substrate can transfer heat to the substrate in time to increase the thermal imaging rate, but due to the existence of the substrate, about 40% of the infrared radiation is absorbed and reflected by the substrate, which reduces the infrared absorption efficiency. In addition, the sacrificial layer The release process is complicated, which often causes adhesion between the structural layer and the sinking bottom, resulting in pixel failure. The infrared FPA with no substrate and fully hollowed out improves the infrared absorption efficiency, but due to its fully hollowed out feature, the energy of the pixel cannot be transmitted out in time and lost, resulting in heat transfer between each pixel, and each pixel cannot be independent Work, thermal crosstalk phenomenon is serious, thermal imaging response time is long, and the reduction of device size has a huge impact on its performance, which limits the reduction of pixel size. the

Contents of the invention

In order to overcome the above-mentioned defects, the utility model provides an optical readout thermal-mechanical infrared detector structure, which not only inherits the advantages of the above-mentioned FPA with substrate and full hollow FPA, but also overcomes their existence Shortcomings. Compared with the FPA with substrate structure, this structure improves the infrared absorption efficiency, and improves the temperature uniformity of the film area compared with the fully hollow FPA, so that each pixel can work independently, and the thermal response rate is improved. At the same time, each pixel is made in On the support layer, there is no need for an additional support frame, which improves the duty cycle; in addition, the design of the upper and lower superimposed deformed cantilever beam structure not only improves the temperature response sensitivity, but also improves the optical fill factor, which is more conducive to the smaller size of the pixel direction development. the

The technical solution adopted by the utility model in order to solve the technical problem is: an optical readout thermal-mechanical infrared detector structure, including several pixel units distributed in an array, and each pixel unit includes: lining Bottom, supporting layer, infrared absorbing layer, reflective plate and double-material cantilever beam, the supporting layer is located on the upper side of the substrate, and the center of the lower side of the substrate is semi-hollowed out; the infrared absorbing layer is spaced apart from Located above the upper side of the support layer, the reflective plate is located on the upper side of the infrared absorbing layer; the bi-material cantilever beams are two, and are symmetrically arranged on the upper side of the support layer in parallel intervals; the Each double-material cantilever beam includes an upper beam and a lower beam arranged in parallel and spaced up and down, the lower beam is composed of a first non-metal layer and a first metal layer, and the first metal layer is located on the upper side of the first non-metal layer , and one end of the lower side of the first non-metallic layer of the lower beam extends downwards and is connected with the support layer to form a whole; the upper beam is composed of a second non-metallic layer and a second metal layer, and the second non-metallic layer is located on the upper side of the second metal layer, and the other end of the second non-metal layer of the upper beam extends downwards along the axial direction and the other end face of the second metal layer respectively to the side of the first non-metal layer. The other ends are connected to form an integral body; one end on the second non-metallic upper beam of the two double-material cantilever beams respectively extends along a plane parallel to the support surface and is connected to the infrared absorbing layer to form an integral body. the

As a further improvement of the present invention, the supporting layer, the first non-metal layer, the second non-metal layer and the infrared absorbing layer are respectively one of a silicon oxide layer and a silicon nitride layer. the

As a further improvement of the present utility model, the first metal layer, the second metal layer and the reflective layer are respectively one of an aluminum layer and a gold layer. the

As a further improvement of the present invention, the direction of the semi-hollowing out of the lower side of the substrate and the direction of the crossbeam of the bimaterial cantilever beam are one of vertical and parallel. the

The beneficial effects of the utility model are: compared with the existing thermo-mechanical IR-FPA structure, the FPA structure has the following advantages:

1. Compared with FPA with a substrate structure, this structure reduces the absorption of infrared radiation by the substrate, effectively improves the infrared absorption efficiency, and then improves the response rate;

2. Compared with the support structure required by the fully hollow FPA, this structure effectively improves the optical fill factor and is more conducive to the reduction of the pixel size;

3. The semi-hollow structure eliminates the thermal crosstalk phenomenon that may occur during thermal imaging, the response time is reduced, and the thermal imaging rate is accelerated;

4. The deformed cantilever beam adopts the multi-fold folding beam deformation superposition technology, which improves the temperature response sensitivity and the response rate is improved;

5. The deformed beam adopts the upper and lower stacking technology, which can effectively improve the optical filling factor of the pixel;

6. It is conducive to the development of pixels to a smaller size. the

Description of drawings

Fig. 1 is the structure schematic diagram of pixel unit array described in the utility model;

Fig. 2 is the structural representation of single pixel unit described in the utility model;

Fig. 3 is the cross-sectional structure schematic diagram of Fig. 2;

Fig. 4 is a schematic diagram of the structure of the dual-material cantilever beam described in the present invention. the

In conjunction with the accompanying drawings, the following explanations are made:

1——Substrate 2——Support layer

3——Infrared absorbing layer 4——Reflective plate

5——Double material cantilever beam 6——Upper beam

7——Lower beam 8——The first non-metallic layer

9——First Metal Layer 10——Second Metal Layer

11——Second non-metallic layer 100——Pixel unit

Detailed ways

An optical readout thermal-mechanical infrared detector structure, including several pixel units 100 distributed in an array, each of which includes: a substrate 1, a support layer 2, an infrared absorption layer 3, and a reflector 4 and a double-material cantilever beam 5, the support layer is located on the upper side of the substrate, and the center of the lower side of the substrate is semi-hollowed out; the interval between the infrared absorbing layers is located above the upper side of the support layer , the reflector is located on the upper side of the infrared absorbing layer; there are two double-material cantilever beams, and they are symmetrically arranged on the upper side of the support layer in parallel intervals; each of the double-material cantilever beams includes up and down parallel The upper beam 6 and the lower beam 7 arranged at intervals, the lower beam is composed of the first non-metallic layer 8 and the first metal layer 9, the first metal layer is located on the upper side of the first non-metallic layer, and the lower beam One end of the lower side of the first non-metallic layer extends downwards and is connected with the support layer to form a whole; the upper beam is composed of a second non-metallic layer 11 and a second metal layer 10, and the second non-metallic layer is located at the on the upper side of the second metal layer, and the other end of the second non-metal layer of the upper beam extends downwards along the axial direction and the other end face of the second metal layer respectively to the other end face of the first non-metal layer connected to form an integral body; one end of the second non-metallic upper beam of the two double-material cantilever beams respectively extends along a plane parallel to the supporting surface and is connected with the infrared absorbing layer to form an integral body. the

Preferably, the support layer, the first non-metal layer, the second non-metal layer and the infrared absorbing layer are respectively silicon oxide layers or silicon nitride layers. the

Preferably, the above-mentioned first metal layer, second metal layer and reflective layer are aluminum layer or gold layer respectively. the

Preferably, the direction of the semi-hollowing out of the lower side of the substrate is perpendicular or parallel to the direction of the beam of the bi-material cantilever beam. the

Claims (4)

1. An optical readout thermal-mechanical infrared detector structure, comprising several pixel units (100) distributed in an array, characterized in that: each of the pixel units includes: a substrate (1), a support layer (2), infrared absorbing layer (3), reflective plate (4) and bimaterial cantilever beam (5), the support layer is located on the upper side of the substrate, and the center of the lower side of the substrate is half Hollow shape; the infrared absorbing layer is spaced above the upper side of the support layer, and the reflector is located on the upper side of the infrared absorbing layer; there are two double-material cantilever beams, and they are arranged symmetrically at parallel intervals. On the upper side of the support layer; each of the bimaterial cantilever beams includes an upper beam (6) and a lower beam (7) arranged in parallel and spaced up and down, and the lower beam is composed of the first non-metallic layer (8) and the first metal Layer (9), the first metal layer is located on the upper side of the first non-metallic layer, and one end of the lower side of the first non-metallic layer of the lower beam extends downwards and is connected with the supporting layer to form an integral body; The upper beam is composed of a second non-metal layer (11) and a second metal layer (10), the second non-metal layer is located on the upper side of the second metal layer, and the second non-metal layer of the upper beam The other end extends downwards along its axial direction and the other end face of the second metal layer and connects with the other end face of the first non-metallic layer to form an integral body; the second non-metallic One end on the top respectively extends along a plane parallel to the support surface and connects with the infrared absorbing layer to form a whole. 2. The optical readout thermal-mechanical infrared detector structure according to claim 1, characterized in that: the supporting layer, the first non-metallic layer, the second non-metallic layer and the infrared absorbing layer are respectively silicon oxide layers and one of the silicon nitride layers. 3. The optical readout thermal-mechanical infrared detector structure according to claim 1, characterized in that: the first metal layer, the second metal layer and the reflective layer are respectively one of an aluminum layer and a gold layer. 4. The optical readout thermal-mechanical infrared detector structure according to claim 1, characterized in that: the direction of the semi-hollowed-out lower side of the substrate is perpendicular to and parallel to the direction of the crossbeam of the bimaterial cantilever beam one.

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