Avalanche photodiode temperature and humidity composite sensor and electronic device

Abstract

This application discloses an avalanche photodiode temperature and humidity composite sensor and electronic device. The composite sensor includes a passivation layer, an avalanche photodiode, a humidity sensing element, and a temperature sensing element. The passivation layer has a first surface and a second surface arranged opposite to each other. The avalanche photodiode is disposed on the first surface of the passivation layer, and the humidity sensing element and the temperature sensing element are integrated on the second surface of the passivation layer. The passivation layer forms electromagnetic shielding and isolation between the photoelectric detection unit and the temperature and humidity sensing unit. This application adopts a double-sided layered integrated layout, which significantly reduces the overall size of the device and achieves miniaturization. Relying on the thermal conductivity and isolation characteristics of the passivation layer, the chip operating temperature can be quickly and accurately acquired to achieve photoelectric detection result calibration and compensation. At the same time, crosstalk between photoelectric signals and sensing signals is avoided, and the backlit humidity sensing element can avoid strong light aging, effectively improving the device's detection accuracy, long-term stability, and adaptability to complex environments.

Description

Technical Field

[0001] This application belongs to the field of sensor equipment technology, specifically relating to an avalanche photodiode temperature and humidity composite sensor and electronic equipment. Background Technology

[0002] Avalanche photodiodes (APDs) possess the capability for detection in low light and at the single-photon level, but existing structures only focus on light signal detection and lack the ability to sense other environmental parameters such as temperature. In practical applications, an external temperature compensation circuit is required for measurement calibration, leading to an increase in the overall device size.

[0003] In related technologies, the above problems are often solved by deploying sensors separately. However, separate deployment often leads to high system complexity and increased costs. Moreover, when multiple sensors work together, signal interference and space occupation conflicts can easily occur. Especially in scenarios such as monitoring confined spaces in aerospace and biomedicine, there is an urgent need to achieve miniaturized integration solutions. Summary of the Invention

[0004] This application provides an avalanche photodiode temperature and humidity composite sensor and electronic device, which aims to achieve miniaturization of multi-parameter sensors while improving detection accuracy and environmental adaptability.

[0005] To achieve the above objectives, the avalanche photodiode temperature and humidity composite sensor provided in this application includes: A passivation layer, comprising a first surface and a second surface disposed opposite to each other; Avalanche photodiode, located on the first surface of the passivation layer; Humidity sensing elements and temperature sensing elements are located on the second surface of the passivation layer; The passivation layer is used to form electromagnetic shielding and isolation between the avalanche photodiode and the humidity sensing element and temperature sensing element.

[0006] In some embodiments, the insulation withstand voltage of the passivation layer is not less than 100V.

[0007] In some embodiments, the passivation layer is a SiNx passivation layer.

[0008] In some embodiments, the thickness of the passivation layer is 200 nm to 800 nm.

[0009] In some embodiments, the avalanche photodiode is a forward-illuminated InP-based SAGCM avalanche photodiode.

[0010] In some embodiments, an avalanche photodiode includes, from top to bottom, an optical window and electrode layer, a P-type contact layer, a multiplication layer, a charge layer, a gradient layer, an absorption layer, a buffer layer, and a substrate layer.

[0011] In some embodiments, the temperature sensing element includes a continuously folded metal sensing film.

[0012] In some embodiments, the humidity sensing element includes interdigitated electrodes and a humidity-sensitive functional medium.

[0013] In some embodiments, the device further includes a housing, which has a sealed light-transmitting window at the position corresponding to the avalanche photodiode and a micro-ventilated structure at the position corresponding to the humidity sensing element.

[0014] This application also provides an electronic device, including the above-mentioned avalanche photodiode temperature and humidity composite sensor.

[0015] In the avalanche photodiode temperature and humidity composite sensor provided in this application, the sensor size can be reduced by separately placing the humidity sensing element, the temperature sensing element, and the avalanche photodiode on the front and back sides of the passivation layer. The humidity and temperature sensing elements are positioned close to the avalanche photodiode, allowing heat to be quickly conducted to the platinum resistance thermometer on the back side, resulting in fast thermal response and low temperature hysteresis. Based on rapid and accurate temperature measurement, the avalanche photodiode measurement results can be further calibrated based on the temperature measurement data, improving detection accuracy. The passivation layer forms electromagnetic shielding, eliminating electromagnetic interference from the avalanche photodiode and improving the detection accuracy of temperature and humidity. Simultaneously, zoned wiring further reduces wiring complexity. Furthermore, the humidity sensing element is positioned on the backlight side, away from strong incident light, avoiding direct sunlight that could cause aging of the humidity-sensitive material and parameter drift, thus improving the long-term stability of the humidity sensor. This achieves miniaturization and integration while improving accuracy and environmental adaptability.

[0016] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic cross-sectional view of a sensor assembly provided in an embodiment of this application; Figure 2 This is a schematic cross-sectional view of a sensor assembly provided in an embodiment of this application; Figure reference numerals: 100-passivation layer, 200-avalanche photodiode, 210-optical window and electrode layer, 220-P-type contact layer, 230-multiplication layer, 240-charge layer, 250-gradient layer, 260-absorption layer, 270-buffer layer and substrate layer, 300-humidity sensing element, 400-temperature sensing element. Detailed Implementation

[0018] The embodiments of this application will now be described in detail with reference to the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0020] In the description of this application, it should be noted that, unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," and similar terms used in this application, mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "inner," "outer," "upper," and "lower" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0021] Avalanche photodiodes (APDs) possess detection capabilities in low light and at the single-photon level. In complex operating environments, timely monitoring of temperature and humidity is crucial for accurate detection and equipment reliability. Addressing these issues through discrete sensor deployment often leads to high system complexity and increased costs. Therefore, there is an urgent need for a solution that achieves miniaturized integration and stable detection capabilities. In view of this, refer to Figure 1 , Figure 2 As shown, the first aspect of this application provides an avalanche photodiode temperature and humidity composite sensor, which improves accuracy and environmental adaptability while achieving miniaturized integration.

[0022] Some embodiments of the avalanche photodiode temperature and humidity composite sensor of this application include: Passivation layer 100, the passivation layer 100 includes a first surface and a second surface disposed opposite to each other; Avalanche photodiode 200 is located on the first surface of passivation layer 100; Humidity sensing element 300 and temperature sensing element 400 are located on the second surface of passivation layer 100; The passivation layer 100 is used to form electromagnetic shielding isolation between the avalanche photodiode 200 and the humidity sensing element 300 and the temperature sensing element 400.

[0023] In the avalanche photodiode temperature and humidity composite sensor of this application embodiment, the sensor size can be reduced by respectively disposing the humidity sensing element 300, the temperature sensing element 400, and the avalanche photodiode 200 on the front and back sides of the passivation layer 100. The humidity sensing element 300 and the temperature sensing element 400 are positioned close to the avalanche photodiode 200, allowing heat to be quickly conducted to the platinum resistance thermometer on the back side, resulting in fast thermal response and low temperature hysteresis. Based on rapid and accurate temperature measurement, the measurement results of the avalanche photodiode 200 can be further calibrated based on the temperature measurement data, improving detection accuracy. The passivation layer 100 can form electromagnetic shielding isolation, eliminating electromagnetic interference from the avalanche photodiode 200 and improving the detection accuracy of temperature and humidity. Simultaneously, partitioned wiring further reduces wiring difficulty. Furthermore, the humidity sensing element 300 is arranged on the backlight side, away from strong incident light, avoiding direct sunlight that could cause aging of the humidity-sensitive material and parameter drift, thus improving the long-term stability of the humidity sensor. This achieves miniaturization and integration while improving accuracy and environmental adaptability.

[0024] In some embodiments, the passivation layer 100 is a SiNx passivation layer.

[0025] It should be noted that SiNx in this application refers to silicon nitride dielectric material, which is a mainstream dense inorganic passivation and insulating material in the field of semiconductor optoelectronic devices. Here, x is the stoichiometric coefficient of silicon nitride, which can be adjusted according to the thin film deposition process conditions to control the elemental composition and physical properties, adapting to the insulation, protection, and thermal conductivity requirements of different devices. Compared to traditional SiO2 silicon oxide dielectric materials, SiNx materials possess comprehensive advantages such as high density, excellent insulation performance, high mechanical strength, strong moisture and seepage resistance, higher thermal conductivity, and good process compatibility, making it a preferred dielectric carrier for optoelectronic composite integrated devices.

[0026] In some embodiments, the insulation withstand voltage of the passivation layer (100) is not less than 100V. The passivation layer has excellent electrical insulation and high voltage isolation performance, which can effectively isolate the high voltage avalanche working signal of the avalanche photodiode from the weak detection analog signal of the temperature and humidity sensor, eliminate crosstalk between high and low voltage signals, and ensure the accuracy of photoelectric detection and the stability of temperature and humidity detection.

[0027] In some embodiments, the passivation layer 100 has a thickness of 200 nm to 800 nm. In the design of this application, the passivation layer 100 serves both to shield electromagnetic signals and to conduct heat. Excessive thickness increases thermal resistance and reduces temperature response; insufficient thickness results in inadequate insulation. A suitable passivation layer thickness provides appropriate thermal conductivity and heat dissipation performance, enabling rapid and uniform conduction of the junction heat generated during the operation of the avalanche photodiode. This allows the back-side platinum resistance temperature sensor to capture the chip's true operating temperature in real time and accurately, with minimal temperature lag and high adhesion. It also serves to shield electromagnetic signals and reduce crosstalk.

[0028] In some embodiments, the avalanche photodiode 200 is a forward-illuminated InP-based SAGCM avalanche photodiode.

[0029] In the above embodiments, the InP-based SAGCM avalanche photodiode is better suited to the passivation layer double-sided integrated architecture. The light-receiving structure on the front side of the device can completely avoid the interference of the temperature and humidity sensing element on the back side blocking the optical path, ensuring the accuracy of photoelectric detection. At the same time, its active junction region is close to the passivation layer, and through its efficient thermal conductivity, the platinum resistance thermometer on the back side can accurately and in real time collect the chip junction temperature. Combined with the electrical isolation performance of the passivation layer, it can effectively isolate the crosstalk between the APD high-voltage avalanche signal and the weak temperature and humidity detection signal, taking into account both optical detection performance and environmental parameter monitoring stability, and adapting to the working requirements of integrated composite sensing.

[0030] In some examples, the avalanche photodiode 200 includes, from top to bottom, an optical window and electrode layer 210, a P-type contact layer 220, a multiplication layer 230, a charge layer 240, a gradient layer 250, an absorption layer 260, a buffer layer, and a substrate layer 270. In a further example, the optical window and electrode layer 210 is mainly composed of Ti / Au metal electrodes and SiO2 / SiNx passivation dielectric, with a light-transmitting window reserved in the middle for low-loss incident light reception and reverse bias electrical connection of the device, while protecting the chip surface and suppressing surface leakage; the P-type contact layer 220 uses heavily doped P... + The InP material is lightly doped to reduce electrode contact resistance, providing an efficient collection channel for photogenerated carriers and reducing signal loss; the multiplication layer 230 uses lightly doped intrinsic InP material, utilizing the hole collisional ionization effect to achieve avalanche multiplication amplification of the optical signal, improving the device's detection sensitivity; the charge layer 240 uses heavily doped N. + The InP material is used to precisely control the internal electric field distribution of the device, realizing a partitioned electric field structure with a weak electric field in the absorption layer and a strong electric field in the multiplication layer; the graded layer 250 uses a compositionally graded InGaAsP alloy material, which can smooth the valence band barrier between the absorption layer and the upper structure, eliminate carrier trapping, reduce device noise, and improve response speed; the absorption layer 260 uses lattice-matched In... 0.53 Ga 0.47As material is mainly used to absorb near-infrared incident light in the 1310–1550 nm range, completing photoelectric conversion and generating photogenerated electron-hole pairs; the buffer layer and substrate layer 270 consist of an InP buffer layer and an N… + The integrated InP substrate can buffer lattice stress, eliminate epitaxial growth defects, reduce dark current, and provide mechanical support and underlying conductive path to ensure stable device operation.

[0031] In some embodiments, the temperature sensing element 400 includes a continuously folded metal sensing film. In some examples, the folded metal sensing film is arranged to coincide with the vertical projection of the optical window of the avalanche photodiode 200. As an example, the temperature sensing element 400 can be a thin-film platinum resistance sensor, specifically a PT100 or PT1000 type platinum resistance sensor. The continuously folded metal sensing film is prepared using high-purity platinum metal material through thin-film deposition and photolithography processes. It is arranged in a serpentine folded pattern and integrally bonded to the second surface of the SiNx passivation layer, coinciding with the vertical projection of the front avalanche photodiode 200. Platinum metal possesses characteristics such as stable temperature coefficient of resistance, high linearity, minimal temperature drift, and excellent anti-aging properties. Leveraging the superior thermal conductivity and temperature uniformity of the SiNx passivation layer, it can rapidly sense changes in the operating junction temperature of the avalanche photodiode 200. Simultaneously, the continuously folded thin-film structure increases the effective length of the sensing film and the temperature measurement coverage area within a limited region, improving temperature sensitivity and uniformity. This allows for real-time and accurate acquisition of dynamic temperature data from the APD chip, providing reliable parameter data for subsequent APD gain temperature compensation and device operating status monitoring.

[0032] In some embodiments, the humidity sensing element 300 includes interdigitated electrodes and a humidity-sensitive functional medium. In some examples, the humidity sensing element 300 is an integrated capacitive humidity sensor, integrally thin-film fabricated on the second surface of a SiNx passivation layer, and is independently arranged from the temperature sensing element 400 without interference. The interdigitated electrodes are formed using a photolithography process with a metal conductive thin film, featuring uniform electrode spacing, stable conductivity, and low parasitic parameters, used to construct a uniform induced electric field. The humidity-sensitive functional medium is a polymer humidity-sensitive thin film material, covering and adhering to the surface and gaps of the interdigitated electrodes. This humidity-sensitive medium undergoes a reversible change in dielectric constant with changes in ambient relative humidity, thereby altering the overall capacitance value of the sensor. By detecting the change in capacitance, the ambient humidity parameter can be accurately calculated. Meanwhile, the humidity sensing element 300 is arranged on the backlight side, which can avoid the aging effect of strong light incident from the front. Combined with the micro-ventilated packaging structure, it can ensure that the ambient water vapor can freely enter and exit and respond quickly. It can monitor the humidity status of the device's working environment in real time, and provide an effective compensation basis for correcting the dark current drift of APD and the degradation of detection noise under high humidity environment.

[0033] In some embodiments, the device further includes a housing with a sealed light-transmitting window corresponding to the avalanche photodiode 200 and a micro-ventilated structure corresponding to the humidity sensing element 300. In this embodiment, the housing provides physical protection and structural definition for the entire device, while also incorporating a partitioned structure design to meet the differentiated functional requirements of dual-sided integration. The sealed light-transmitting window is sealed with a high-transmittance insulating material, perfectly corresponding to the light-receiving area of ​​the avalanche photodiode 200. This ensures lossless penetration of near-infrared incident light and provides sealed protection for the photoelectric detection area, effectively isolating external dust, moisture, and corrosive gases from intrusion. This prevents contamination and aging of the APD active layer, suppresses the increase in dark current and the decrease in detection accuracy, and ensures the sealing and stability of the photoelectric detection system. The micro-ventilated structure corresponding to the humidity sensing element 300 is a micrometer-level ventilated channel structure, allowing free exchange of moisture between the internal and external air without introducing large amounts of external pollutants. This enables the humidity-sensitive medium to sense real-time changes in ambient humidity, ensuring the response speed and detection accuracy of humidity detection. This partitioned packaging structure perfectly solves the technical contradiction that traditional integrated devices cannot simultaneously meet the requirements of APD sealing detection and humidity permeability detection, taking into account both the high stability of photoelectric detection and the accuracy of temperature and humidity detection, and greatly improving the environmental adaptability and operational reliability of composite sensors.

[0034] In some embodiments, the photoelectric signal leads of the avalanche photodiode 200, the humidity detection leads of the humidity sensing element 300, and the temperature detection leads of the temperature sensing element 400 are partitioned and independently routed to achieve complete electrical isolation between the photoelectric working circuit and the temperature and humidity detection circuit. In this embodiment, based on the SiNx passivation layer double-sided layered integrated structure, the device adopts partitioned wiring and independent bonding technology to physically partition the high-voltage, high-dynamic photoelectric signal leads and the weak analog sensing signal leads. Specifically, the photoelectric signal leads of the avalanche photodiode 200 are concentrated in the light-receiving area of ​​the first surface of the passivation layer to transmit the photoelectric detection signal amplified by the high-voltage avalanche; the humidity detection leads and temperature detection leads are uniformly and neatly arranged in the backlight sensing area of ​​the second surface of the passivation layer to transmit two low-amplitude, high-precision environmental detection signals respectively. All types of leads are independent, the routing paths do not intersect, and the bonding pads are arranged in partitions, completely avoiding electrical coupling and signal crosstalk between different functional circuits. This partitioned wiring structure can prevent the high-voltage operating noise of the APD from coupling to the temperature and humidity detection circuit, avoid interference and distortion of weak sensing signals, and prevent the sensing circuit from causing reverse interference to the photoelectric detection signal. This effectively improves the accuracy of photoelectric detection and the stability of temperature and humidity detection, and further optimizes the overall anti-interference capability and operational reliability of the composite sensor.

[0035] A second aspect of this application provides an electronic device including the aforementioned avalanche photodiode temperature and humidity composite sensor. This electronic device includes the sensor assembly and therefore also possesses the technical advantages offered by the sensor assembly.

[0036] In the description of this specification, references to terms such as "some embodiments," "examples," or "some examples" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An avalanche photodiode temperature and humidity composite sensor, characterized in that, include: A passivation layer (100) includes a first surface and a second surface disposed opposite to each other; An avalanche photodiode (200) is located on the first surface of the passivation layer (100); A humidity sensing element (300) and a temperature sensing element (400) are located on the second surface of the passivation layer (100); The passivation layer (100) is used to form electromagnetic shielding isolation between the avalanche photodiode (200) and the humidity sensing element (300) and the temperature sensing element (400).

2. The avalanche photodiode temperature and humidity composite sensor according to claim 1, characterized in that: The insulation withstand voltage of the passivation layer (100) is not less than 100V.

3. The avalanche photodiode temperature and humidity composite sensor according to claim 1, characterized in that: The passivation layer (100) is a SiNx passivation layer.

4. The avalanche photodiode temperature and humidity composite sensor according to claim 1, characterized in that: The passivation layer (100) has a thickness of 200 nm to 800 nm.

5. The avalanche photodiode temperature and humidity composite sensor according to claim 1, characterized in that: The avalanche photodiode (200) is a positive illumination InP-based SAGCM avalanche photodiode.

6. The avalanche photodiode temperature and humidity composite sensor according to claim 5, characterized in that: The avalanche photodiode (200) includes, from top to bottom, an optical window and electrode layer (210), a P-type contact layer (220), a multiplication layer (230), a charge layer (240), a gradient layer (250), an absorption layer (260), a buffer layer, and a substrate layer (270).

7. The avalanche photodiode temperature and humidity composite sensor according to claim 1, characterized in that: The temperature sensing element (400) includes a continuously folded metal sensing film.

8. The avalanche photodiode temperature and humidity composite sensor according to claim 1, characterized in that: The humidity sensing element (300) includes interdigitated electrodes and a humidity-sensitive functional medium.

9. The avalanche photodiode temperature and humidity composite sensor according to claim 1, characterized in that: It also includes a packaging housing, which has a sealed light-transmitting window at the position corresponding to the avalanche photodiode (200) and a micro-ventilated structure at the position corresponding to the humidity sensing element (300).

10. An electronic device, characterized in that, Including the avalanche photodiode temperature and humidity composite sensor as described in any one of claims 1 to 9.

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