Infrared temperature sensor and preparation method thereof

Abstract

The invention discloses an infrared temperature sensor and a preparation method thereof, and belongs to the technical field of semiconductors. The infrared temperature sensor comprises at least one sensing unit, and each sensing unit comprises a substrate, a semiconductor layer, a barrier layer, a first resonator, a second resonator and a wave-absorbing coating which are stacked. The first resonator is connected with a sweep frequency signal and sends out a frequency signal under the action of the sweep frequency signal, and the second resonator receives the frequency signal under the action of resonance. When external temperature changes, the wave-absorbing coating absorbs heat to cause temperature rise of the sensing unit, a heterostructure formed by the semiconductor layer and the barrier layer generates surface polarization charges under the pyroelectric action, the polarization charges influence the resonant frequency of the resonator, and by analyzing the deviation condition of a frequency signal relative to a sweep frequency signal, the temperature of the sensing unit can be measured. And the temperature change condition can be judged.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to an infrared temperature sensor and a preparation method thereof. Background Art

[0002] At present, temperature sensors still have problems such as low measurement accuracy, low sensitivity, poor anti-interference ability, or complex system and high manufacturing cost. Infrared temperature sensors in particular have low sensitivity and poor measurement accuracy, and their performance is greatly reduced or even fails in low temperature environments.

[0003] Based on this, how to improve the sensitivity of infrared temperature sensors has become an urgent problem to be solved in this field. Summary of the invention

[0004] The present application provides an infrared temperature sensor and a preparation method thereof, aiming to improve the sensitivity of the infrared temperature sensor and expand the measurement range of the infrared temperature sensor.

[0005] In a first aspect, the present application provides an infrared temperature sensor, comprising at least one sensing unit, the sensing unit comprising a substrate, a semiconductor layer, a barrier layer, a first resonator, a second resonator, and an absorbing coating. The semiconductor layer is disposed on the substrate, the barrier layer is disposed on a side of the semiconductor layer away from the substrate, the first resonator and the second resonator are both disposed on a side of the barrier layer away from the substrate and are electrically connected to the barrier layer respectively, and the absorbing coating is disposed on a side of the first resonator away from the substrate and on a side of the second resonator away from the substrate.

[0006] In some embodiments, the materials of the semiconductor layer and the barrier layer both include Group IIIA-VA elements.

[0007] In some embodiments, the material of the semiconductor layer includes at least one of gallium nitride, gallium arsenide, or indium gallium arsenide, and the material of the barrier layer includes at least one of indium gallium nitride, aluminum gallium nitride, indium phosphide, aluminum gallium arsenide, or indium aluminum arsenide.

[0008] In some embodiments, the sensing unit further includes a buffer layer disposed between the substrate and the semiconductor layer.

[0009] In some embodiments, the absorbing coating layer includes a first absorbing coating layer and a second absorbing coating layer, the first resonator includes a first comb-tooth portion, the second resonator includes a second comb-tooth portion, and the first comb-tooth portion and the second comb-tooth portion are arranged crosswise. The first absorbing coating layer is located on a side of the first comb-tooth portion away from the substrate, and the orthographic projection of the first absorbing coating layer on the substrate overlaps with the orthographic projection of the first comb-tooth portion on the substrate. The second absorbing coating layer is located on a side of the second comb-tooth portion away from the substrate, and the orthographic projection of the second absorbing coating layer on the substrate overlaps with the orthographic projection of the second comb-tooth portion on the substrate.

[0010] In some embodiments, the shape of the orthographic projection of the first absorbing coating on the substrate is the same as the shape of the orthographic projection of the first comb teeth on the substrate; the shape of the orthographic projection of the second absorbing coating on the substrate is the same as the shape of the orthographic projection of the second comb teeth on the substrate.

[0011] In some embodiments, the absorbing coating material includes at least one of carbon nanotubes, zinc oxide, lead zirconate titanate, or polyvinylidene fluoride.

[0012] In some embodiments, the infrared temperature sensor further includes a cavity, and the cavity is arranged around the sensing unit along a direction parallel to the plane where the substrate is located, and the cavity is also arranged between the substrate and the semiconductor layer.

[0013] In a second aspect, an embodiment of the present application further provides a method for preparing an infrared temperature sensor, wherein the infrared temperature sensor includes at least one sensing unit, and forming the sensing unit includes the following steps S10 to S30:

[0014] Step S10: forming stacked semiconductor layers and barrier layers in sequence on a substrate.

[0015] Step S20: forming a first resonator and a second resonator, wherein the first resonator and the second resonator are both located on a side of the barrier layer away from the substrate and are electrically connected to the barrier layer respectively.

[0016] Step S30: forming a microwave absorbing coating, wherein the microwave absorbing coating is located on a side of the first resonator away from the substrate and on a side of the second resonator away from the substrate.

[0017] In some embodiments, after forming the absorbing coating, the above steps further include: etching the semiconductor layer and the substrate to form a cavity, wherein the cavity is located around the sensing unit and between the substrate and the semiconductor layer in a direction parallel to the plane of the substrate.

[0018] In the infrared temperature sensor provided in the embodiment of the present application, the sensing unit includes a substrate, a semiconductor layer, a barrier layer, a first resonator, a second resonator and an absorbing coating. During the operation of the sensor, the first resonator can be connected to a frequency sweep signal, and under the action of the frequency sweep signal, the first resonator emits a frequency signal, and under the resonance, the second resonator receives the frequency signal emitted by the first resonator and outputs it to an external detection device. When the external temperature changes, the absorbing coating absorbs heat, causing the temperature of the sensing unit to rise. The heterostructure composed of the semiconductor layer and the barrier layer will generate surface polarization charges under the action of pyroelectricity. The polarization charge will affect the resonant frequency of the resonator, that is, compared with the frequency sweep signal connected to the first resonator, the frequency signal received by the second resonator will be offset. By analyzing the offset of the frequency signal compared to the frequency sweep signal, the temperature change can be judged.

[0019] The above-mentioned sensing unit is more sensitive to temperature. Compared with the related art, the change of surface polarization charge is more obvious, and the influence on the resonant frequency is also more obvious. Based on this, the infrared temperature sensor has a higher sensitivity. In addition, by setting the wave-absorbing coating, the absorption efficiency of the sensing unit to infrared waves can be improved, so that the temperature in the sensing unit rises rapidly, further improving the change of surface polarization charge and the influence on the resonant frequency, thereby improving the sensitivity and accuracy of the infrared temperature sensor and expanding the measurement range of the infrared temperature sensor.

[0020] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 A top view of an infrared temperature sensor provided in an embodiment of the present application;

[0023] Figure 2 for Figure 1 A cross-sectional view of the mid-infrared temperature sensor along the section line AA';

[0024] Figure 3 A top view of another infrared temperature sensor provided in an embodiment of the present application;

[0025] Figure 4 for Figure 3 A cross-sectional view of the mid-infrared temperature sensor along the section line BB';

[0026] Figure 5 A flow chart of a method for preparing an infrared temperature sensor provided in an embodiment of the present application;

[0027] Figure 6 to Figure 13 A diagram of the steps for preparing an infrared temperature sensor provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0029] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be construed in an open, inclusive sense, ie, meaning "including, but not limited to."

[0030] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0031] When describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components are in direct physical or electrical contact with each other.

[0032] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0033] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0034] Exemplary embodiments are described herein with reference to cross-sectional views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0035] Examples of the embodiments 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 application, and cannot be understood as limiting the present application.

[0036] At present, in the temperature sensor related technology, thermistor type sensors have low cost, but low measurement accuracy, and can only perform simple measurements or realize threshold detection functions. If the resistance temperature sensor wants to achieve wide range and high linearity testing capabilities, a lot of linear compensation work needs to be done, which greatly increases the complexity and manufacturing cost of the system. Thermocouple temperature sensors have extremely low sensitivity, and within the working range, the nonlinearity of the temperature to voltage transfer function often requires compensation circuits or table lookups. Infrared temperature sensors have low sensitivity and poor measurement accuracy. They do not perform well in low temperature environments and have a small measurement range.

[0037] To solve the above problems, the present application provides an infrared temperature sensor, which includes at least one sensing unit, such as Figure 1 to Figure 4 As shown, Figure 1 A top view of an infrared temperature sensor provided in an embodiment of the present application, Figure 2 for Figure 1 The cross-sectional view of the mid-infrared temperature sensor along the section line AA', Figure 3 A top view of another infrared temperature sensor provided in an embodiment of the present application, Figure 4 for Figure 3 The cross-sectional view of the mid-infrared temperature sensor along the section line BB'. It should be noted that Figure 1 to Figure 4 It is mainly used to illustrate the basic structure of the infrared temperature sensor and the relative position relationship between the film layers, and is not used to limit the specific morphology.

[0038] Taking the infrared temperature sensor including a sensing unit 100 as an example, the sensing unit 100 includes a substrate 1, a semiconductor layer 2, a barrier layer 3, a first resonator 4, a second resonator 5, and an absorbing coating 6. The substrate 1, the semiconductor layer 2, and the barrier layer 3 are stacked, the first resonator 4 and the second resonator 5 are arranged in the same layer and are both arranged on the side of the barrier layer 3 away from the substrate 1, the first resonator 4 and the second resonator 5 are electrically connected to the barrier layer 3 respectively, and the absorbing coating 6 is arranged on the side of the first resonator 4 away from the substrate 1 and on the side of the second resonator 5 away from the substrate 1.

[0039] During operation, the first resonator 4 can be connected to a frequency sweep signal. For example, the frequency range of the frequency sweep signal can be 1000Hz to 10MHz. Under the action of the frequency sweep signal, the first resonator 4 emits a frequency signal. Under the resonance, the second resonator 5 can be used to receive the frequency signal emitted by the first resonator 4 and output it to an external detection device. It should be noted that the functions of the first resonator 4 and the second resonator 5 have a certain symmetry. For example, the second resonator 5 can also be used to connect to a frequency sweep signal, and the first resonator 4 is used to output the frequency signal generated by the resonance.

[0040] When the external temperature changes, the absorbing coating 6 absorbs heat, causing the temperature of the sensing unit 100 to rise. The heterostructure composed of the semiconductor layer 2 and the barrier layer 3 will generate surface polarization charges under the action of pyroelectricity. The polarization charges will affect the resonant frequency of the resonator. That is, compared with the swept frequency signal connected to the first resonator 4, the frequency signal received by the second resonator 5 will be offset. By analyzing the offset of the frequency signal compared to the swept frequency signal, the temperature change can be determined.

[0041] The above-mentioned sensing unit is more sensitive to temperature. Compared with the related art, the change of the surface polarization charge is more obvious, and the influence on the resonant frequency is also more obvious. Based on this, the infrared temperature sensor has a higher sensitivity. In addition, by providing the wave-absorbing coating 6, the absorption efficiency of the sensing unit 100 to infrared waves can be improved, so that the temperature in the sensing unit 100 rises rapidly, further improving the change of the surface polarization charge and the influence on the resonant frequency, thereby improving the sensitivity of the infrared temperature sensor. In addition, by adjusting the frequency of the sweep signal within a certain range, the accuracy of the infrared temperature sensor can be improved, and the measurement range of the infrared temperature sensor can be expanded.

[0042] In some embodiments, the materials of the semiconductor layer 2 and the barrier layer 3 both include Group IIIA-VA elements, such as silicon, gallium, nitrogen, arsenic, germanium, and the like.

[0043] In some embodiments, the material of the semiconductor layer 2 includes at least one of gallium nitride, gallium arsenide or indium gallium arsenide, and the material of the barrier layer 3 includes at least one of indium gallium nitride, aluminum gallium nitride, indium phosphide, aluminum gallium arsenide or indium aluminum arsenide.

[0044] The single crystal structure material formed by the above materials has relatively excellent pyroelectric properties and electrostrictive effects, which enables the device to have high linearity and high-precision temperature detection capabilities over a wide range. For example, when the temperature change is low, the temperature sensor can also generate more surface polarization charges on the two opposite surfaces of the semiconductor layer 2 and the barrier layer 3, thereby affecting the resonant frequency, thereby improving the sensitivity of the device.

[0045] In some embodiments, Figure 2 or Figure 4 As shown, to avoid lattice mismatch and dislocation, the sensor unit 100 further includes a buffer layer 7 disposed between the substrate 1 and the semiconductor layer 2. The buffer layer 7 is used to reduce lattice mismatch, lower dislocation density, facilitate the formation of surface polarization charges, and improve device sensitivity.

[0046] In some embodiments, Figure 3 or Figure 4As shown, the absorbing coating 6 includes a first absorbing coating 61 and a second absorbing coating 62, the first resonator 4 includes a first comb-tooth portion 41, the second resonator 5 includes a second comb-tooth portion 51, and the first comb-tooth portion 41 and the second comb-tooth portion 51 are arranged crosswise. The first absorbing coating 61 is located on the side of the first comb-tooth portion 41 away from the substrate 1, and the orthographic projection of the first absorbing coating 61 on the substrate 1 overlaps with the orthographic projection of the first comb-tooth portion 41 on the substrate 1. The second absorbing coating 62 is located on the side of the second comb-tooth portion 51 away from the substrate 1, and the orthographic projection of the second absorbing coating 62 on the substrate overlaps with the orthographic projection of the second comb-tooth portion 51 on the substrate 1.

[0047] The comb-tooth morphology of the first comb-tooth portion 41 and the second comb-tooth portion 51 and the cross-setting of the two are conducive to improving the resonance effect, ensuring that the second resonator 5 receives the frequency signal emitted by the first resonator 4. According to the positional relationship between the first comb-tooth portion 41 and the second comb-tooth portion 51, the absorbing coating 6 is divided into a first absorbing coating 61 and a second absorbing coating 62. The first absorbing coating 61 is connected to the first comb-tooth portion 41, and the second absorbing coating 62 is connected to the second comb-tooth portion 51, which can ensure that the absorbing coating effectively absorbs infrared waves and conducts temperature to the heterogeneous structure using the resonator. The separate setting of the first absorbing coating 61 and the second absorbing coating 62 can also reduce the influence of the absorbing coating on the propagation path of the sound wave during the resonance process.

[0048] The orthographic projection of the first absorbing coating 61 on the substrate 1 overlaps with the orthographic projection of the first comb-tooth portion 41 on the substrate 1 , which may be partially overlapped or completely overlapped. The larger the overlapping area, the more favorable it is for transmitting the temperature increased by absorbing the infrared waves by the first absorbing coating 61 to the heterogeneous structure through the first comb-tooth portion 41 . The same is true for the second absorbing coating 62 .

[0049] For example, in some embodiments, Figure 3-4 In the figure, the shape of the orthographic projection of the first absorbing coating layer 61 on the substrate 1 is the same as the shape of the orthographic projection of the first comb-tooth portion 41 on the substrate 4. The shape of the orthographic projection of the second absorbing coating layer 62 on the substrate 1 is the same as the shape of the orthographic projection of the second comb-tooth portion 51 on the substrate 1. Figure 3 As shown, the first comb-tooth portion 41 is covered by a first absorbing coating 61 , and the second comb-tooth portion 51 is covered by a second absorbing coating 62 . Figure 3-4 It is only used to illustrate the relative positional relationship between the first comb-tooth portion 41 and the second comb-tooth portion 51 , and does not limit the number of comb teeth.

[0050] In some embodiments, the material of the absorbing coating 6 includes at least one of carbon nanotubes, zinc oxide, lead zirconate titanate, or polyvinylidene fluoride. The above materials have good performance in absorbing infrared waves and are relatively sensitive to temperature changes. By absorbing infrared waves, the temperature of the sensing unit 100 rises rapidly, so that the heterostructure generates more surface polarization charges under the pyroelectric effect, which enhances the effect on the resonant frequency, thereby improving the sensitivity of the infrared temperature sensor.

[0051] In some embodiments, the infrared temperature sensor further includes a cavity K1 . The cavity K1 is disposed around the sensing unit 100 in a direction parallel to the plane where the substrate 1 is located, and the cavity K1 is also disposed between the substrate 1 and the semiconductor layer 2 .

[0052] The setting of the cavity K1 can reduce the conduction loss of heat in the solid, so that the temperature rise caused by the absorption of infrared waves by the absorbing coating 6 is retained as much as possible in the sensing unit 100, especially in the heterostructure located below the first resonator 4 and the first resonator 5, to avoid the temperature from rapidly decreasing after rising, which is beneficial for the heterostructure to generate more and more stable surface polarization charges under the pyroelectric effect, thereby improving the measurement sensitivity and measurement accuracy.

[0053] On the other hand, the present application also provides a method for preparing an infrared temperature sensor, such as Figure 5 As shown, Figure 5 This is a flow chart of a method for preparing an infrared temperature sensor provided in an embodiment of the present application. Figure 6 to Figure 13 A diagram of the steps for preparing an infrared temperature sensor provided in an embodiment of the present application.

[0054] The external temperature sensor includes at least one sensing unit 100, and forming the sensing unit includes the following steps S10 to S30:

[0055] Step S10: Figure 6-7 As shown, a semiconductor layer 2 and a barrier layer 3 are stacked in sequence on a substrate 1 .

[0056] First, if Figure 6 As shown, a stacked structure of a substrate 1, a semiconductor layer 2 and a barrier thin layer 30 is formed. The substrate 1 is usually a silicon substrate, or it can also be a sapphire substrate, and the semiconductor layer 2 usually includes IIIA-VA group elements, such as gallium nitride, gallium arsenide or indium gallium arsenide. In order to avoid the generation of lattice mismatch and dislocation, a buffer layer 7 is usually provided between the substrate 1 and the semiconductor layer 2 to reduce the lattice mismatch and reduce the dislocation density, thereby improving the performance and reliability of the device. For example, the material of the buffer layer 7 includes aluminum nitride, the material of the semiconductor layer 2 includes gallium nitride, and the material of the barrier layer 3 includes aluminum gallium nitride.

[0057] Afterwards, if Figure 7As shown, the barrier thin layer 30 is patterned, and the barrier thin layer 30 in the redundant area is etched away, and the barrier layer 3 is retained. Figure 1 or Figure 3 The projection area of ​​the barrier layer 3 on the substrate 1 is shown, and the barrier thin layer 30 in the area is retained by patterning, and the excess barrier thin layer 30 around is removed by etching. Exemplarily, the barrier thin layer 30 can be removed by etching with an inductively coupled plasma etching process.

[0058] Step S20: Figure 8 As shown, a first resonator 4 and a second resonator 5 are formed. The first resonator 4 and the second resonator 5 are both located on a side of the barrier layer 3 away from the substrate 1 and are electrically connected to the barrier layer 3 respectively.

[0059] Along the Z-axis direction, the first resonator 4 and the second resonator 5 are at the same film layer height, and the two are formed by the same process. To improve the resonance effect, for example, Figure 3 As shown, the first resonator 4 includes a first comb-tooth portion 41 , and the second resonator 5 includes a second comb-tooth portion 51 . The first comb-tooth portion 41 and the second comb-tooth portion 51 are arranged crosswise.

[0060] Figure 8 Taking the first resonator 4 as an example, the number of teeth of the first comb-tooth portion 41 can be rationally designed by comprehensively considering factors such as process cost, process accuracy, device size and resonance effect, and is only used for illustration.

[0061] like Figure 8 As shown, after metal material is deposited on the barrier layer 3 and patterned, the first resonator 4 and the second resonator 5 are formed. The metal material includes but is not limited to gold, aluminum, platinum, molybdenum, etc., and the thickness ranges from 50nm to 1000nm.

[0062] Then as Fig. 9 As shown, a passivation layer 8 is formed, and the passivation layer 8 covers the semiconductor layer 2, the barrier layer 3, and covers a portion of the first resonator 4 and a portion of the second resonator 5. Figure 1 or Figure 3 In the peripheral area shown, the portion of the first resonator 4 exposed by the passivation layer 8 is used to connect to an external circuit, for example, to access a frequency sweep signal. Similarly, the portion of the second resonator 5 exposed by the passivation layer 8 is used to connect to an external circuit, for example, to connect to an external signal receiving and analyzing device. The portion of the first comb-tooth portion 41 exposed by the passivation layer 8 and the portion of the second comb-tooth portion 51 exposed by the passivation layer 8 are both used to connect to the subsequently formed absorbing coating.

[0063] Step S30: Fig.10As shown, a absorbing coating 6 is formed. The absorbing coating 6 is located on a side of the first resonator 4 away from the substrate 1 , and is located on a side of the second resonator 5 away from the substrate 1 .

[0064] In order to make the device have good infrared wave absorption performance and be more sensitive to temperature changes, the material of the absorbing coating 6 may include at least one of carbon nanotubes, zinc oxide, lead zirconate titanate or polyvinylidene fluoride, with a thickness ranging from 5nm to 500nm.

[0065] Since the heat conduction capacity of the passivation layer 8 is weaker than that of the first resonator 4 and the second resonator 5, the absorbing coating 6 penetrates the passivation layer 8 and is connected to the first resonator 4 and the second resonator 5, which is beneficial to conduct as much heat as possible from the infrared wave absorbed by the absorbing coating 6 to the heterostructure under the first resonator 4 and the second resonator 5, thereby improving the sensitivity of the device.

[0066] For example, in some embodiments, Figure 3 As shown, the absorbing coating 6 includes a first absorbing coating 61 and a second absorbing coating 62. The orthographic projection of the first absorbing coating 61 on the substrate 1 overlaps with the orthographic projection of the first comb-tooth portion 41 on the substrate 1, and the orthographic projection of the second absorbing coating 62 on the substrate overlaps with the orthographic projection of the second comb-tooth portion 51 on the substrate 1. Fig.11 As shown, Fig.11 Only the first absorbing coating 61 is shown, and the second absorbing coating 62 is not shown.

[0067] In some embodiments, after the absorbing coating 6 is formed, in order to further improve the sensitivity of the device, the preparation process may also include: etching the semiconductor layer 2 and the substrate 1 to form a cavity K1, and the cavity K1 is located around the sensing unit 100 along a direction parallel to the plane of the substrate 1, and is located between the substrate 1 and the semiconductor layer 2.

[0068] For example, Fig.12 As shown, an inductively coupled plasma etching process may be first used to etch and remove a portion of the passivation layer 8 , the semiconductor layer 2 , and the buffer layer 7 to form a via hole V1 , so that the via hole V1 exposes a portion of the substrate 1 .

[0069] Then as Fig.13 As shown, the substrate 1 is etched with xenon difluoride using the via hole V1, and finally a cavity K1 is formed. Figure 1 or Figure 3 As shown, the cavity K1 is arranged around the sensing unit 100, and, as shown in FIG. Figure 2 or Figure 4 As shown, the cavity K1 is also disposed between the substrate 1 and the semiconductor layer 2. That is, the cavity K1 enables the middle portion of the sensor unit 100 to form a structure similar to a suspended island.

[0070] The preparation method has a relatively simple preparation process, and the infrared temperature sensor prepared has high sensitivity. In addition, the cavity K1 formed by etching can also reduce the conduction loss of heat in the solid, which is beneficial to retain more of the temperature rise caused by the absorption of infrared waves by the absorbing coating 6 in the middle part, and is beneficial for the heterogeneous structure to generate more and more stable surface polarization charges under the action of pyroelectricity, thereby enhancing the influence on the resonant frequency, thereby improving the measurement sensitivity and measurement accuracy.

[0071] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that a person skilled in the art can think of within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An infrared temperature sensor, characterized in that: comprising at least one sensing unit; The sensing unit comprises: substrate; A semiconductor layer is disposed on the substrate; A barrier layer, disposed on a side of the semiconductor layer away from the substrate; The first resonator and the second resonator are both arranged on a side of the barrier layer away from the substrate and are electrically connected to the barrier layer respectively; The absorbing coating is arranged on a side of the first resonator away from the substrate, and is arranged on a side of the second resonator away from the substrate.

2. The infrared temperature sensor according to claim 1, characterized in that: The materials of the semiconductor layer and the barrier layer both include group IIIA-VA elements.

3. The infrared temperature sensor according to claim 1, characterized in that: The material of the semiconductor layer includes at least one of gallium nitride, gallium arsenide or indium gallium arsenide, and the material of the barrier layer includes at least one of indium gallium nitride, aluminum gallium nitride, indium phosphide, aluminum gallium arsenide or indium aluminum arsenide.

4. The infrared temperature sensor according to claim 1, characterized in that: The sensing unit further includes a buffer layer, and the buffer layer is arranged between the substrate and the semiconductor layer.

5. The infrared temperature sensor according to claim 1, characterized in that: The absorbing coating comprises a first absorbing coating and a second absorbing coating; the first resonator comprises a first comb-tooth portion, the second resonator comprises a second comb-tooth portion, and the first comb-tooth portion and the second comb-tooth portion are arranged crosswise; The first absorbing coating layer is located on a side of the first comb-tooth portion away from the substrate, and an orthographic projection of the first absorbing coating layer on the substrate overlaps with an orthographic projection of the first comb-tooth portion on the substrate; The second absorbing coating layer is located on a side of the second comb-tooth portion away from the substrate, and an orthographic projection of the second absorbing coating layer on the substrate overlaps with an orthographic projection of the second comb-tooth portion on the substrate.

6. The infrared temperature sensor according to claim 5, characterized in that: The shape of the orthographic projection of the first absorbing coating on the substrate is the same as the shape of the orthographic projection of the first comb-tooth portion on the substrate; The shape of the orthographic projection of the second absorbing coating layer on the substrate is the same as the shape of the orthographic projection of the second comb-tooth portion on the substrate.

7. The infrared temperature sensor according to claim 1, characterized in that: The wave absorbing coating material includes at least one of carbon nanotubes, zinc oxide, lead zirconate titanate or polyvinylidene fluoride.

8. The infrared temperature sensor according to claim 1, characterized in that: The infrared temperature sensor further comprises a cavity, which is arranged around the sensing unit in a direction parallel to the plane where the substrate is located, and the cavity is also arranged between the substrate and the semiconductor layer.

9. A method for preparing an infrared temperature sensor, characterized in that: The infrared temperature sensor comprises at least one sensing unit; Forming the sensing unit includes: sequentially forming a stacked semiconductor layer and a barrier layer on a substrate; forming a first resonator and a second resonator, wherein the first resonator and the second resonator are both located on a side of the barrier layer away from the substrate and are electrically connected to the barrier layer respectively; A wave absorbing coating is formed. The wave absorbing coating is located on a side of the first resonator away from the substrate and on a side of the second resonator away from the substrate.

10. The preparation method according to claim 9, characterized in that: After forming the radar absorbing coating, the method further comprises: The semiconductor layer and the substrate are etched to form a cavity; along a direction parallel to the plane where the substrate is located, the cavity is located around the sensing unit and between the substrate and the semiconductor layer.

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