Pyroelectric infrared detector and manufacturing method thereof

Abstract

The invention discloses a pyroelectric infrared detector and a manufacturing method of the pyroelectric infrared detector. The pyroelectric infrared detector comprises a substrate; the bottom electrode layer is arranged above the substrate and is connected with the substrate through a bonding layer, and the bottom electrode layer is provided with an electrode part which protrudes upwards; the pyroelectric functional layer is arranged above the bottom electrode layer, an electrode groove is formed in the pyroelectric functional layer, and the electrode part is exposed out of the upper surface of the pyroelectric functional layer through the electrode groove; the top electrode layer is arranged on the upper surface of the pyroelectric functional layer and is separated from the electrode part in the horizontal direction, and an infrared absorption layer is prepared on a top electrode. The pyroelectric infrared detector provided by the embodiment of the invention has the advantages of low process difficulty, low cost, high integration level, high reliability and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device manufacturing, and in particular to a pyroelectric infrared detector and a method for manufacturing the pyroelectric infrared detector. Background Art

[0002] Infrared detectors are components that convert infrared radiation energy into electrical energy. They are widely used in military reconnaissance and guidance, civil safety and health, environmental monitoring and protection, industrial and traffic security inspection, and astronomical science research. According to the difference in working temperature, they can be divided into cooled infrared detectors and uncooled infrared detectors. Uncooled infrared detectors have the advantages of no need for refrigeration, no radiation, low power consumption, and low cost, and have become one of the important development directions of infrared detectors. According to different working principles, uncooled infrared sensors can be further divided into thermistor infrared detectors, thermopile infrared detectors, and pyroelectric infrared detectors. Among them, the core of the pyroelectric infrared detector is the infrared sensitive element material with pyroelectric effect. When infrared radiation irradiates the sensitive element, the temperature of the sensitive element rises, resulting in a change in the spontaneous polarization intensity, thereby generating a voltage signal. Therefore, the pyroelectric infrared detector has significant advantages in response time and detection rate, and is suitable for applications that require fast response and high sensitivity. The thickness of the pyroelectric infrared sensitive element and the structure of the device have a great influence on the performance and integration of the pyroelectric infrared detector.

[0003] There are two main structures of pyroelectric infrared detectors in related technologies for achieving good thermal insulation function, one is a self-supporting thin film structure, and the other is a suspended film structure with a supporting substrate. The bottom electrodes of both structures are led out from the back of the device, which not only greatly affects the integration of the device, but also requires precise process control, including the production of through holes, the filling of electrode materials, and the connection of lead wires, etc. These steps increase the complexity and cost of the process. In addition, the through-hole lead-out electrodes may have problems such as loose connection and easy breakage, which affects the reliability and stability of the device. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a pyroelectric infrared detector, which has the advantages of low process difficulty, low cost, high integration, and high reliability.

[0005] The invention also provides a method for manufacturing the pyroelectric infrared detector.

[0006] To achieve the above-mentioned purpose, a pyroelectric infrared detector is provided according to an embodiment of the first aspect of the present invention, and the pyroelectric infrared detector includes: a substrate; a bottom electrode layer, the bottom electrode layer is arranged above the substrate and connected to the substrate, the bottom electrode layer has an electrode portion protruding upward; a pyroelectric functional layer, the pyroelectric functional layer is arranged above the bottom electrode layer, the pyroelectric functional layer is provided with an electrode groove, and the electrode portion is exposed from the upper surface of the pyroelectric functional layer through the electrode groove; and a top electrode layer, the top electrode layer is arranged on the upper surface of the pyroelectric functional layer and is spaced apart from the electrode portion in a horizontal direction.

[0007] The pyroelectric infrared detector according to the embodiment of the present invention has the advantages of low process difficulty, low cost, high integration, high reliability, etc.

[0008] In addition, the pyroelectric infrared detector according to the above embodiment of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present invention, an infrared absorption layer is provided on the upper surface of the top electrode layer.

[0010] According to an embodiment of the present invention, the bottom electrode layer and the substrate are bonded and connected via a bonding layer.

[0011] According to an embodiment of the present invention, the bonding layer is a curable organic adhesive layer or a curable resin adhesive layer.

[0012] According to an embodiment of the present invention, the depth of the electrode groove is 5-20 micrometers and the electrode groove occupies 10%-30% of the pyroelectric functional layer in the width direction of the electrode groove.

[0013] According to an embodiment of the present invention, a thermal insulation hole is provided on the substrate.

[0014] According to an embodiment of the second aspect of the present invention, a method for manufacturing a pyroelectric infrared detector is provided, and the method for manufacturing the pyroelectric infrared detector comprises the following steps:

[0015] Providing a pyroelectric functional layer and a substrate, wherein the pyroelectric functional layer has a first surface and a second surface opposite to each other;

[0016] Processing an electrode groove on the first surface of the pyroelectric functional layer;

[0017] A bottom electrode layer is formed on the first surface of the pyroelectric functional layer, wherein the bottom electrode layer extends into the electrode groove;

[0018] connecting the bottom electrode layer to the substrate;

[0019] Thinning the pyroelectric functional layer so that the bottom electrode layer is exposed from the second surface;

[0020] A top electrode layer is prepared on the second surface.

[0021] The manufacturing method of the pyroelectric infrared detector according to the embodiment of the present invention has the advantages of low process difficulty, low cost, high integration, high reliability, etc.

[0022] According to one embodiment of the present invention, after preparing the top electrode layer on the second surface, the method further comprises:

[0023] An infrared absorbing layer is prepared on the top electrode layer.

[0024] According to one embodiment of the present invention, after preparing the infrared absorption layer on the top electrode layer, the method further comprises:

[0025] Thermally insulating holes are machined in the substrate.

[0026] According to an embodiment of the present invention, connecting the bottom electrode layer to the substrate includes bonding the bottom electrode layer to the substrate using a bonding layer.

[0027] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0029] Figure 1 Schematic diagram of the structure of a pyroelectric infrared detector according to an embodiment of the present invention.

[0030] Figure 2 Schematic diagram of the manufacturing process of a pyroelectric infrared detector according to an embodiment of the present invention.

[0031] Figure 3 4 is a flow chart of a method for manufacturing a pyroelectric infrared detector according to an embodiment of the present invention.

[0032] Figure numerals: pyroelectric infrared detector 1 , substrate 10 , bottom electrode layer 20 , electrode portion 21 , pyroelectric functional layer 30 , electrode groove 31 , first surface 32 , second surface 33 , top electrode layer 40 , infrared absorption layer 50 , bonding layer 60 . DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The following describes a pyroelectric infrared detector 1 according to an embodiment of the present invention with reference to the accompanying drawings.

[0037] like Figure 1-Figure 3 As shown, the pyroelectric infrared detector 1 according to the embodiment of the present invention includes a substrate 10 , a bottom electrode layer 20 , a pyroelectric functional layer 30 and a top electrode layer 40 .

[0038] The bottom electrode layer 20 is disposed above the substrate 10 and connected to the substrate 10 (in the vertical direction as shown in FIG. Figure 1 As shown by the arrow in the figure and for the convenience of description only, it is not a limitation on the actual setting direction), the bottom electrode layer 20 has an electrode portion 21 protruding upward. The pyroelectric functional layer 30 is arranged above the bottom electrode layer 20, and the pyroelectric functional layer 30 is provided with an electrode groove 31, and the electrode portion 21 is exposed from the upper surface of the pyroelectric functional layer 30 through the electrode groove 31. The top electrode layer 40 is arranged on the upper surface of the pyroelectric functional layer 30 and is spaced apart from the electrode portion 21 in the horizontal direction.

[0039] Specifically, the pyroelectric functional layer 30 can be a lithium tantalate single crystal material layer or a lithium niobate single crystal material layer. The pyroelectric single crystals of lithium tantalate and lithium niobate have excellent pyroelectric properties and small dielectric constants, and are excellent materials for making pyroelectric infrared detectors.

[0040] The substrate 10 is a silicon material, a glass material or a lithium tantalate single crystal material.

[0041] The top electrode layer 40 and the bottom electrode layer 20 may both be double-layer structures, and both include a chromium material layer and a gold material layer, or both include a titanium material layer and a gold material layer to improve conductivity and adhesion. For example, when forming the top electrode layer 40, a chromium material layer may be first formed on the upper surface of the pyroelectric functional layer 30, and then a gold material layer may be formed on the upper surface of the chromium material layer.

[0042] According to the pyroelectric infrared detector 1 of the embodiment of the present invention, by providing an electrode groove 31 on the pyroelectric functional layer 30 and providing an electrode portion 21 on the bottom electrode layer 20, so that the electrode portion 21 is exposed from the upper surface of the pyroelectric functional layer 30 through the electrode groove 31, the bottom electrode layer 20 and the pyroelectric functional layer 30 can form a wrapping support, and by connecting the bottom electrode layer 20 to the substrate 10, the substrate 10 can support the overall structure, thereby improving the structural reliability and stability of the pyroelectric infrared detector 1.

[0043] Furthermore, by providing an electrode groove 31 on the pyroelectric functional layer 30 and providing an electrode portion 21 on the bottom electrode layer 20, the electrode portion 21 is exposed from the upper surface of the pyroelectric functional layer 30 through the electrode groove 31, and providing a top electrode layer 40 on the upper surface of the pyroelectric functional layer 30, the top electrode layer 40 and the bottom electrode layer 20 can be both located on the upper surface of the pyroelectric functional layer 30, thereby achieving the coplanarity of the top electrode layer 40 and the bottom electrode layer 20, making the lead-in of the pyroelectric infrared detector 1 more convenient. Compared with the pyroelectric infrared detector in the related art, the problem that the bottom electrode of the pyroelectric infrared detector in the related art needs to be led out from the back side is avoided. There is no need to lead out the electrode from the back side, which reduces the control accuracy requirements of the manufacturing process, reduces the process complexity and cost, and is more conducive to improving the integration of the pyroelectric infrared detector 1. It can also avoid the problems of loose connection and easy breakage caused by leading out the electrode through the through hole, thereby improving the reliability and stability of the pyroelectric infrared detector 1.

[0044] Therefore, the pyroelectric infrared detector 1 according to the embodiment of the present invention has the advantages of low process difficulty, low cost, high integration, and high reliability.

[0045] The following describes a pyroelectric infrared detector 1 according to a specific embodiment of the present invention with reference to the accompanying drawings.

[0046] In some specific embodiments of the present invention, Figure 1-Figure 3As shown, the pyroelectric infrared detector 1 according to the embodiment of the present invention includes a substrate 10 , a bottom electrode layer 20 , a pyroelectric functional layer 30 and a top electrode layer 40 .

[0047] Advantageously, if Figure 1 As shown, the upper surface of the top electrode layer 40 is provided with an infrared absorption layer 50. Specifically, the infrared absorption layer 50 can be selected from a carbon-based material layer, a metal absorption layer or a high molecular organic polymer material layer. The carbon-based material layer includes carbon black, carbon nanotubes, graphite, etc., which can be prepared by high-temperature inkjet, electrostatic spraying, screen printing or vapor deposition. The metal absorption layer includes a blackened metal film, such as gold black, silver black, platinum black and nickel-chromium alloy, which can be prepared by a thin film deposition process such as evaporation or magnetron. The high molecular organic polymer layer includes photosensitive ink, photosensitive conductive glue, etc., which can be prepared by a spin coating process. By providing the infrared absorption layer 50, the absorption capacity of the pyroelectric infrared detector 1 to infrared radiation can be improved, and the detection sensitivity of the pyroelectric infrared detector 1 can be improved.

[0048] More advantageously, if Figure 1 As shown, the bottom electrode layer 20 and the substrate 10 are bonded and connected via the bonding layer 60. In this way, not only can the connection between the bottom electrode layer 20 and the substrate 10 be achieved, but also the low thermal conductivity of the bonding layer 60 also acts as an insulating layer for the pyroelectric functional layer 30, which prevents the heat of the pyroelectric infrared detector 1 from being lost to the environment, thereby improving the detection sensitivity and accuracy of the pyroelectric infrared detector 1, and can also play a supporting role on the lower surface of the pyroelectric functional layer 30, further improving the structural stability of the pyroelectric infrared detector 1.

[0049] Optionally, the bonding layer 60 is a curable organic adhesive layer or a curable resin adhesive layer. Specifically, the bonding layer 60 can be prepared by spin coating or screen printing. In this way, the bonding layer 60 has good connection strength and thermal insulation performance.

[0050] Specifically, the depth of the electrode groove 31 is 5-20 microns and the electrode groove occupies 10%-30% of the pyroelectric functional layer in the width direction of the electrode groove, so that the electrode groove 31 has a reasonable size and ensures the structural strength of the pyroelectric functional layer 30 while facilitating the lead wire.

[0051] More specifically, a heat insulating hole is provided on the substrate 10 , so as to further improve the heat insulation of the pyroelectric infrared detector 1 , prevent heat loss, and improve the detection sensitivity and accuracy of the pyroelectric infrared detector 1 .

[0052] Specifically, the thickness of the infrared absorption layer 50 is 0.2-5 microns. In this way, the integration of the pyroelectric infrared detector 1 can be improved while ensuring the absorption effect of the infrared absorption layer 50. The thickness of the bottom electrode layer 20 is 200-600 nanometers, and the thickness of the top electrode layer 40 is 200-600 nanometers. In this way, the integration of the pyroelectric infrared detector 1 can be improved while ensuring the structural strength and supporting effect of the top electrode layer 40 and the bottom electrode layer 20.

[0053] Reference below Figure 1-Figure 3 The manufacturing method of the pyroelectric infrared detector according to the embodiment of the present invention is described. The manufacturing method of the pyroelectric infrared detector according to the embodiment of the present invention comprises the following steps:

[0054] S1, providing a pyroelectric functional layer 30 and a substrate 10, wherein the pyroelectric functional layer 30 has a first surface 32 and a second surface 33 opposite to each other;

[0055] S2, processing an electrode groove 31 on the first surface 32 of the pyroelectric functional layer 30;

[0056] S3, preparing a bottom electrode layer 20 on the first surface 32 of the pyroelectric functional layer 30, wherein the bottom electrode layer 20 extends into the electrode groove 31;

[0057] S4, connecting the bottom electrode layer 20 to the substrate 10;

[0058] S5, thinning the pyroelectric functional layer 30 so that the bottom electrode layer 20 is exposed from the second surface 33;

[0059] S6 , preparing a top electrode layer 40 on the second surface 33 .

[0060] What needs to be understood here is that Figure 2 As shown, the pyroelectric functional layer 30 can be flipped between different processes according to the process requirements. The first surface 32 and the second surface 33 of the pyroelectric functional layer 30 will change position as it is flipped. In step S5, the position of the second surface 33 will change as the pyroelectric functional layer 30 is thinned.

[0061] Specifically, if Figure 2 As shown, steps S1 and S2 are as follows Figure 2 As shown in process a, step S3 is as follows Figure 2 As shown in process b, step S4 is as follows Figure 2 As shown in process c, step S5 is as follows Figure 2 As shown in process d, step S6 is as follows Figure 2 As shown in process e.

[0062] According to the manufacturing method of the pyroelectric infrared detector of the embodiment of the present invention, the electrode groove 31 is processed on the first surface 32 of the pyroelectric functional layer 30, and the bottom electrode layer 20 is prepared on the first surface 32 of the pyroelectric functional layer 30. The bottom electrode layer 20 extends into the electrode groove 31, and the bottom electrode layer 20 is connected to the substrate 10. The bottom electrode layer 20 and the pyroelectric functional layer 30 can form a wrapping support, and by connecting the bottom electrode layer 20 to the substrate 10, the substrate 10 can support the overall structure, thereby improving the structural reliability and stability of the pyroelectric infrared detector.

[0063] Furthermore, the electrode groove 31 is processed on the first surface 32 of the pyroelectric functional layer 30, the bottom electrode layer 20 is prepared on the first surface 32 of the pyroelectric functional layer 30, the bottom electrode layer 20 extends into the electrode groove 31, the bottom electrode layer 20 is connected to the substrate 10, the pyroelectric functional layer 30 is thinned, the bottom electrode layer 20 is exposed from the second surface 33, and the top electrode layer 40 is prepared on the second surface 33, so that the top electrode layer 40 and the bottom electrode layer 20 can be located on the upper surface of the pyroelectric functional layer 30, thereby realizing the top electrode layer 40. 0 and the bottom electrode layer 20 are coplanar, which makes it more convenient to lead the pyroelectric infrared detector. Compared with the pyroelectric infrared detector in the related art, it avoids the problem that the bottom electrode of the pyroelectric infrared detector in the related art needs to be led out from the back side. There is no need to lead out the electrode from the back side, which reduces the control accuracy requirements of the manufacturing process, reduces the process complexity and cost, and is more conducive to improving the integration of the pyroelectric infrared detector. It can also avoid the problems of loose connection and easy breakage caused by leading out the through-hole electrode, thereby improving the reliability and stability of the pyroelectric infrared detector.

[0064] Therefore, the manufacturing method of the pyroelectric infrared detector according to the embodiment of the present invention has the advantages of low process difficulty, low cost, high integration, and high reliability.

[0065] Advantageously, if Figure 2 As shown, after step S6, the following steps are also included:

[0066] S7 . Prepare an infrared absorption layer 50 on the top electrode layer 40 .

[0067] Specifically, step S6 is as follows: Figure 2 As shown in process f. The infrared absorption layer 50 can be a carbon material layer, a metal absorption layer or a high molecular organic polymer material layer. The carbon material layer includes carbon black, carbon nanotubes, graphite, etc., which can be prepared by high temperature inkjet, electrostatic spraying, screen printing or vapor deposition. The metal absorption layer includes a blackened metal film, such as gold black, silver black, platinum black and nickel-chromium alloy, which can be prepared by thin film deposition processes such as thermal evaporation or magnetron. The high molecular organic polymer layer includes photosensitive ink, photosensitive conductive glue, etc., which can be prepared by spin coating or screen printing.

[0068] By providing the infrared absorption layer 50 , the absorption capability of the pyroelectric infrared detector to infrared radiation can be improved, thereby improving the detection sensitivity of the pyroelectric infrared detector.

[0069] More advantageously, if Figure 2 As shown, after step S7, the following steps are also included:

[0070] S8. Processing a thermal insulation hole on the substrate 10. This can further improve the thermal insulation of the pyroelectric infrared detector, prevent heat loss, and improve the detection sensitivity and accuracy of the pyroelectric infrared detector.

[0071] Specifically, Figure 2 As shown, step S4 includes bonding the bottom electrode layer 20 to the substrate 10 using a bonding layer 60. Specifically, the bonding layer 60 is a curable organic adhesive layer or a curable resin adhesive layer. The bonding layer 60 can be prepared by spin coating or screen printing. In this way, the bonding layer 60 has good connection strength and thermal insulation performance. In this way, not only can the connection between the bottom electrode layer 20 and the substrate 10 be achieved, but the low thermal conductivity of the bonding layer 60 also acts as an insulating layer for the pyroelectric functional layer 30, which prevents the heat of the pyroelectric infrared detector from being lost to the environment, improves the detection sensitivity and accuracy of the pyroelectric infrared detector, and can also play a supporting role on the lower surface of the pyroelectric functional layer 30, further improving the structural stability of the pyroelectric infrared detector.

[0072] Reference below Figure 1-Figure 3 A method for manufacturing a pyroelectric infrared detector according to an embodiment of the present invention is described.

[0073] A single-side polished pyroelectric single crystal material is prepared as the pyroelectric functional layer 30, and a metal mask, an organic resin mask or a dielectric mask is used to cover a part of the pyroelectric functional layer 30. A linear electrode groove 31 of 5-20 microns is etched on the polished side of the pyroelectric functional layer 30 by etching, and a boss is formed on the pyroelectric functional layer 30, and the width of the boss is 30-100 microns. The cross section of the pyroelectric functional layer 30 after etching is as follows: Figure 2 As shown in step a;

[0074] A double-layer metal bottom electrode layer 20 is prepared on the etched pyroelectric functional layer 30 by electron beam evaporation or magnetron sputtering, for example, Cr / Au are deposited in sequence, wherein Cr is deposited to improve the adhesion of Au on the pyroelectric functional layer 30. The bottom electrode layer 20 has a thickness of 200-600 nanometers. The cross section after the bottom electrode layer 20 is deposited is as follows: Figure 2 As shown in step b;

[0075] Then, the pyroelectric functional layer 30 and the through-hole substrate 10 are bonded at room temperature by using a room temperature bonding method, using a curable organic glue with low thermal conductivity as the bonding layer 60. The cross section after bonding is as follows: Figure 2 As shown in step c;

[0076] The pyroelectric functional layer 30 is thinned by combining mechanical thinning and chemical polishing, and the thinning is stopped after the bottom electrode layer 20 is exposed, so that the top of the bottom electrode layer 20 is led out, which facilitates the coplanarity of the top and bottom electrodes. Figure 2 As shown in step d;

[0077] The top electrode layer 40 is formed on the surface of the thinned and polished pyroelectric functional layer 30 by electron beam evaporation or magnetron sputtering. The thickness of the top electrode layer 40 is about 200-600 nanometers. The cross section of the top electrode layer 40 after preparation is as follows: Figure 2 As shown in step e;

[0078] An infrared absorption layer 50 is prepared on the top electrode layer 40. The infrared absorption layer 50 can be made of carbon materials, metal absorption layers or high molecular organic polymers. The thickness of the infrared absorption layer 50 is 0.2-5 microns. The cross-sectional view after the absorption layer is prepared is as follows: Figure 2 As shown in step f.

[0079] The bottom electrode layer 20, the pyroelectric functional layer 30, the top electrode layer 40, the infrared absorption layer 50 and the bonding layer 60 surfaces and the back of the substrate 10 are protected by a photoresist mask by a lift-off process, and the back of the substrate 10 is anisotropically etched by a potassium hydroxide solution wet etching method to obtain a microporous structure as a thermal insulation hole, thereby improving the thermal insulation of the device. The cross section after the through hole is prepared is shown in FIG. Figure 2 As shown in step g, the preparation of the pyroelectric infrared detector is completed.

[0080] Reference below Figure 1-Figure 3 The manufacturing method of the pyroelectric infrared detector according to some specific embodiments of the present invention is further described.

[0081] A double-sided polished lithium tantalate single crystal with a thickness of 300-800 microns is prepared as the pyroelectric functional layer 30, a layer of photoresist is spin-coated on the surface, and a patterned mask is formed on the surface of the lithium tantalate single crystal through a lift-off process. A linear channel with a depth of 5-20 microns is etched in the unmasked area as an electrode groove 31 by etching. After etching, the excess photoresist on the surface is washed off, and a boss is formed in the middle of the lithium tantalate single crystal;

[0082] A double-layer metal bottom electrode layer 20 is prepared on the etched lithium tantalate single crystal by magnetron sputtering. The thinned lithium tantalate single crystal is placed in the sample stage of magnetron sputtering. The vacuum is first pumped to below 10Pa using a mechanical pump, and then the vacuum is pumped to below 10-4Pa using a molecular pump. Argon gas is introduced until the pressure in the chamber reaches 1Pa. The DC power supply is set to 45W, the sample stage speed is 15 rpm, the deposition thickness is monitored by a film thickness meter, and 100nm chromium and 100nm gold are sequentially evaporated as the gate layer;

[0083] Then, a curable organic glue with low thermal conductivity is evenly spin-coated on the surface of the lithium tantalate single crystal by a room temperature bonding method, and after being aligned with the substrate 10 and applying a certain pressure, the bonding sheet is placed in a curing device for curing so that the single crystal and the through-hole substrate 10 are bonded at room temperature;

[0084] Use a thinning machine and a 1000-mesh coarse grinding wheel to quickly thin the lithium tantalate single crystal from 500 microns to 20 microns, and then use a 300-mesh fine grinding wheel to thin the lithium tantalate single crystal until the bottom electrode layer 20 is exposed and stop, so as to realize the top lead of the bottom electrode, which is convenient for achieving the coplanarity of the top and bottom electrodes. The thinned lithium tantalate single crystal is stage-annealed at 150 degrees Celsius for 30 minutes to remove the residual stress of the single crystal and improve the yield rate. Select a suitable pickling solution, immerse the single crystal completely in the pickling solution, or evenly spray the pickling solution on the surface, and determine the duration of immersion or spraying. Use an alkaline solution or a large amount of clean water to rinse the surface of the single crystal to remove acidic residues. Finally, the single crystal is dried to remove residual moisture and prevent re-oxidation or contamination;

[0085] The metal mask is used to expose the lithium tantalate of the convex part on the surface of the thinned and polished lithium tantalate single crystal, and a metal Cr / Au double-layer top electrode layer 40 is prepared by magnetron sputtering and the like, and the steps are the same as those for preparing the bottom electrode layer 20. The thickness of the Cr / Au double-layer top electrode is about 200-600 nanometers;

[0086] A graphite layer is applied on the surface of the top electrode by screen printing as the infrared absorption layer 50. The thickness of the infrared absorption layer 50 is 0.2-5 microns;

[0087] The device surface and part of the back side of the Si wafer substrate 10 are protected by a photoresist mask using a stripping process, and the back side of the substrate 10 is anisotropically etched using a potassium hydroxide solution wet etching method to obtain a microporous structure, thereby improving the thermal insulation of the device and completing the preparation of a pyroelectric infrared detector based on a lithium tantalate single crystal.

[0088] In some embodiments, the material of the double-layer metal bottom electrode may also be Ti / Au.

[0089] In some embodiments, the infrared absorption layer 50 may also be a porous black gold material layer, which is prepared by introducing appropriate nitrogen gas when sputtering the gold electrode of the top electrode layer 40 .

[0090] Other structures and operations of the pyroelectric infrared detector 1 and the method for manufacturing the pyroelectric infrared detector according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0092] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A pyroelectric infrared detector, characterized in that: include: substrate; A bottom electrode layer, the bottom electrode layer is arranged above the substrate and connected to the substrate, the bottom electrode layer has an electrode portion protruding upward; A pyroelectric functional layer, wherein the pyroelectric functional layer is disposed above the bottom electrode layer, and an electrode groove is disposed on the pyroelectric functional layer, and the electrode portion is exposed from the upper surface of the pyroelectric functional layer through the electrode groove; A top electrode layer is disposed on an upper surface of the pyroelectric functional layer and is spaced apart from the electrode portion in a horizontal direction.

2. The pyroelectric infrared detector according to claim 1, characterized in that: An infrared absorption layer is disposed on the upper surface of the top electrode layer.

3. The pyroelectric infrared detector according to claim 1, characterized in that: The bottom electrode layer and the substrate are bonded and connected via a bonding layer.

4. The pyroelectric infrared detector according to claim 3, characterized in that: The bonding layer is a curable organic adhesive layer or a curable resin adhesive layer.

5. The pyroelectric infrared detector according to claim 1, characterized in that: The depth of the electrode groove is 5-20 micrometers and the electrode groove occupies 10%-30% of the pyroelectric functional layer in the width direction of the electrode groove.

6. The pyroelectric infrared detector according to claim 1, characterized in that: The substrate is provided with a thermal insulation hole.

7. A method for manufacturing a pyroelectric infrared detector, characterized in that: The following steps are involved: Providing a pyroelectric functional layer and a substrate, wherein the pyroelectric functional layer has a first surface and a second surface opposite to each other; Processing an electrode groove on the first surface of the pyroelectric functional layer; A bottom electrode layer is formed on the first surface of the pyroelectric functional layer, wherein the bottom electrode layer extends into the electrode groove; connecting the bottom electrode layer to the substrate; Thinning the pyroelectric functional layer so that the bottom electrode layer is exposed from the second surface; A top electrode layer is prepared on the second surface.

8. The method for manufacturing a pyroelectric infrared detector according to claim 7, characterized in that: After preparing the top electrode layer on the second surface, the method further comprises: An infrared absorbing layer is prepared on the top electrode layer.

9. The method for manufacturing a pyroelectric infrared detector according to claim 8, characterized in that: After preparing the infrared absorption layer on the top electrode layer, the method further comprises: Thermally insulating holes are machined in the substrate.

10. The method for manufacturing a pyroelectric infrared detector according to claim 7, characterized in that: The connecting the bottom electrode layer to the substrate includes bonding the bottom electrode layer to the substrate using a bonding layer.

Images