Photodetector chip, distance sensor, and electronic device

Abstract

In this application, a photodetector chip (100), a distance sensor (10), and an electronic device (1) are provided. The photodetector chip (100) includes a first electrode (110), a substrate (120), a light absorption layer (140), a top layer (150), a second electrode (180), and a filter layer (170). The substrate (120) is provided on one side of the first electrode (110). The light absorption layer (140) is provided on the side of the substrate (120) away from the first electrode (110). The top layer (150) is provided on the side of the light absorption layer (140) away from the substrate (120). The second electrode (180) is in contact with the top layer (150) and is provided on the side of the top layer (150) away from the light absorption layer (140). The filter layer (170) is provided on the side of the light absorption layer (140) away from the substrate (120) and is located on the side of the second electrode (180) close to the top layer (150). The filter layer (170) is used to filter signals with a wavelength less than 1300 nm and transmit detection signals with a wavelength of 1300 nm or more to reach the light absorption layer (140).

Description

Technical Field

[0001] Reference to Related Applications This application claims priority to Chinese Patent Application No. 202211407177.4, filed on November 10, 2022, with the application title "Photodetector Chip, Distance Sensor and Electronic Device", and all the contents of this prior application are incorporated herein by reference.

[0002] This application relates to the technical field of chips, and specifically to photodetector chips, distance sensors and electronic devices.

Background Art

[0003] With the development of science and technology, electronic devices with a photodetection function are being applied more and more widely. An electronic device usually realizes the photodetection function by including a photodetector chip. For example, a distance sensor in an electronic device realizes distance sensing by including a photodetector chip. Current electronic devices (such as mobile phones) usually include a liquid crystal display screen and a distance sensor. The distance sensor is arranged under the liquid crystal display screen, and the distance sensor usually receives the reflected detection signal by including a silicon-based photodetector chip. However, when the photodetector chip in the related art is applied to a distance sensor, the detection distance is not very accurate.

Summary of the Invention

[0004] In a first aspect, an embodiment of the present application provides a photodetector chip. The photodetector chip includes a first electrode, a substrate, a light absorption layer, a top layer, a second electrode, and a filter layer. The substrate is provided on one side of the first electrode. The light absorption layer is provided on a side of the substrate away from the first electrode. The top layer is provided on a side of the light absorption layer away from the substrate. The second electrode is in contact with the top layer and is provided on a side of the top layer away from the light absorption layer. The filter layer is provided on a side of the light absorption layer away from the substrate and is located on a side of the second electrode close to the top layer. The filter layer is used to filter signals with a wavelength less than 1300 nm and transmit detection signals with a wavelength of 1300 nm or more to reach the light absorption layer.

[0005] In a second aspect, the present application provides a distance sensor. The distance sensor includes a transmitting chip for emitting a detection signal and the photodetector chip described in the first aspect. The filter layer of the photodetector chip is used to filter signals with a wavelength less than 1300 nm and transmit detection signals with a wavelength of 1300 nm or more.

[0006] In a third aspect, the present application provides an electronic device. The electronic device includes a display screen having a display area and the distance sensor described in the second aspect. The distance sensor is provided on one side of the display screen and is provided corresponding to the display area of the display screen. The transmitting chip of the distance sensor is used to emit a detection signal toward the display screen, and the photodetector chip of the distance sensor is used to receive the detection signal transmitted through the display screen. The wavelength of the detection signal is 1300 nm or more.

[0007] In this embodiment, a filter layer is provided on the photodetector chip. The filter layer is provided on the side away from the substrate of the light absorption layer and is located on the side closer to the top layer of the second electrode. The filter layer is used to filter signals of light with a wavelength less than 1300 nm (for example, visible light with a wavelength less than 750 nm). Thereby, the portion of light with a wavelength less than 1300 nm that enters the light absorption layer is reduced or even eliminated. Therefore, for light with a wavelength less than 1300 nm (for example, visible light with a wavelength less than 750 nm), the responsivity of the light absorption layer in the photodetector chip according to this embodiment is small (for example, less than 0.02 A / W). When the photodetector chip is applied to a distance sensor, the detection distance becomes accurate.

Brief Description of the Drawings

[0008] Hereinafter, in order to more clearly explain the technical solutions of the embodiments of the present application, the drawings used in the embodiments will be briefly introduced. Obviously, the drawings used in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings of the embodiments of the present application, the technical solutions of the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0010] Terms such as "first", "second", etc. in the specification, claims and above drawings of the present application are for distinguishing different objects and not for explaining a specific order. Also, the terms "comprising", "having" and any variations thereof are intended to cover and not exclude including other components. For example, a process, method, system, product, or device including a series of operations or units is not limited to the listed operations or units, and may selectively include operations or units not listed, or may selectively include other operations or units specific to these processes, methods, products, or devices.

[0011] As used herein, "example" or "embodiment" means that a particular feature, structure, or characteristic described in connection with an example or embodiment can be included in at least one embodiment of the present application. The use of such terms anywhere in the specification does not necessarily indicate the same embodiment, nor does it indicate an independent or alternative embodiment that is mutually exclusive with other embodiments. One of ordinary skill in the art can explicitly or implicitly understand that the examples described herein can be combined with other examples.

[0012] With the development of science and technology, electronic device 1 with a light detection function is being applied more and more widely. Electronic device 1 usually realizes the light detection function by including a photodetector chip 100. For example, distance sensor 10 in electronic device 1 realizes distance sensing by including a photodetector chip 100 (Si PD). Current electronic devices 1 (such as mobile phones or tablet computers, etc.) usually include a liquid crystal display screen 30 and a distance sensor 10. Distance sensor 10 is disposed under liquid crystal display screen 30, and distance sensor 10 usually receives the reflected detection signal by including a silicon-based photodetector chip. Specifically, the detection signal (usually infrared light of 940 nm) can pass through liquid crystal display screen 30 and be received by photodetector chip 100.

[0013] For electronic device 1 including an OLED display screen 30, since the transmittance of OLED display screen 30 for infrared light of 940 nm that can be received by a silicon-based photodetector chip is very low, it is not possible to dispose a silicon-based photodetector chip under OLED display screen 30. When applying a silicon-based photodetector chip to electronic device 1 including an OLED display screen 30, usually it is necessary to make a hole in display screen 30, and it is not possible to realize a full screen for electronic device 1.

[0014] Light with a wavelength greater than 1300 nm (e.g., 1310 nm) can pass through the OLED display screen 30 and has a high transmittance. In order to realize the full screen of the electronic device 1 equipped with the OLED display screen 30, usually, light with a wavelength greater than 1300 nm (e.g., 1310 nm) is adopted as the detection signal. On the other hand, the maximum wavelength that a silicon-based photodetector chip can receive is 1064 nm. Therefore, in the related technology (not the prior art), by adopting a photodetector chip 100 (InGaAs PD) made of InGaAs material as the photosensitive element of the distance sensor 10 (P-Sensor), a detection signal with a wavelength greater than 1300 nm (e.g., 1310 nm) can be received.

[0015] Considering the actual application of the distance sensor 10 in the electronic device 1, the photodetector chip 100 made of InGaAs material applied to the distance sensor 10 needs to meet two main functions. The first function is to have no influence or almost no response to light (visible light) with a wavelength of 1300 nm or less (e.g., 750 nm), that is, to avoid the interference of ambient light (visible light) around the electronic device 1 to the distance sensor 10 (for example, the responsivity is less than 0.02 A / W). The second function is to have a relatively high responsivity to light with a wavelength of 1300 nm or more (e.g., 1310 nm).

[0016] According to the characteristics of the InGaAs material, the InGaAs material has a relatively high responsivity to light with a wavelength greater than 1300 nm (e.g., 1310 nm). However, the InGaAs material can absorb light with a wavelength of 750 nm or less, and the response of the photodetector chip 100 made of InGaAs material in the related technology to light with a wavelength of 750 nm or less is usually about 0.1 A / W, and the requirement that the responsivity is less than 0.02 A / W cannot be realized.

[0017] Referring to FIG. 1, FIG. 1 is a diagram showing the responsivities of InGaAs and Si-based materials for each wavelength. In FIG. 1, the horizontal axis is the wavelength, with the unit being nm. The vertical axis is the responsivity, also called the response rate or response, with the unit being mA / mW. What is denoted as Si in FIG. 1 indicates the responsivity of the Si-based material for each wavelength, and what is denoted as InGaAs in FIG. 1 indicates the responsivity of the InGaAs material for each wavelength. As can be seen from this, the responsivity of the InGaAs material for light with a wavelength less than 750 nm is relatively large. Specifically, the response to light with a wavelength of 750 nm or less is usually about 0.1 A / W, and the requirement that the responsivity is less than 0.02 A / W cannot be achieved.

[0018] Hereinafter, the photodetector chip 100 of the InGaAs material in the related technology (not the prior art) will be described. In order to easily understand the structure and beneficial effects of the photodetector provided by the embodiments of the present application, before introducing the photodetector provided by the embodiments of the present application, the photodetector provided by the related technology will be introduced. Referring to FIGS. 2 and 3 together, FIG. 2 is a plan view of a photodetector chip provided by one embodiment of the related technology, and FIG. 3 is a schematic cross-sectional view taken along line A-A of the photodetector chip in FIG. 2. The photodetector in the related technology (not the prior art) includes a first electrode 110, a substrate 120, a buffer layer 130, a light absorption layer 140, a top layer 150, a contact layer 160, a passivation layer 210, a transmission enhancement film 220, and a second electrode 180. The first electrode 110, the substrate 120, the buffer layer 130, the light absorption layer 140, the top layer 150, the contact layer 160, and the passivation layer 210 are sequentially stacked and provided. The passivation layer 210 has a through hole 220a, and a part of the transmission enhancement film 220 and the second electrode 180 are provided in the through hole 220a, and a part of the second electrode 180 is provided on the contact layer 160.

[0019] The light absorption layer 140 includes an InGaAs material. In other words, the light absorption layer 140 is an InGaAs light absorption layer 140. Therefore, this photodetector chip 100 is also called a photodetector chip made of InGaAs material. The detection signal can enter the light absorption layer 140 through the transmission enhancement film 220, and the light absorption layer 140 absorbs the detection signal and responds to the detection signal.

[0020] According to the characteristics of the InGaAs material, the InGaAs material has a relatively high responsivity to light with a wavelength greater than 1300 nm (for example, 1310 nm). However, the InGaAs material can absorb light with a wavelength of 750 nm or less, and the response of the InGaAs material photodetector chip 100 in the related art to light with a wavelength of 750 nm or less is usually about 0.1 A / W, and the requirement that the responsivity is less than 0.02 A / W cannot be achieved.

[0021] Next, the photodetector chip 100 provided by each embodiment of the present application will be described. Referring to FIGS. 4 and 5 together, FIG. 4 is a plan view of a photodetector chip provided by one embodiment of the present application, and FIG. 5 is a schematic cross-sectional view taken along line B-B of the photodetector chip in FIG. 4 in one embodiment. The photodetector chip 100 can be applied to devices such as smart driving, sweeping robots, mobile phones, tablet computers, notebook computers, handheld computers, personal computers (PCs), personal digital assistants (PDAs), portable media players (PMPs), earphones, cameras, smart wearable devices, smart screens, display screens, and wind power generation devices. For example, the photodetector chip 100 can be applied to distance measurement and obstacle avoidance in smart driving, or to distance measurement and obstacle avoidance of a sweeping robot, or to proximity sensing of mobile phones, tablet computers, notebook computers, handheld computers, PCs, PDAs, smart wearable devices, smart screens, display screens, and portable media players, or to ear insertion detection of earphones, or to atmospheric exploration of cameras, or the photodetector chips 100 constituting the array can realize the photographing function of a camera, or the photodetector chip 100 can be applied to, for example, distortion detection of wind power generation blades in a wind power generation device. As understood, the above application fields of the photodetector chip 100 should not be understood as limitations of the photodetector chip 100 provided by the embodiments of the present application. This photodetector chip 100 includes a first electrode 110, a substrate 120, a light absorption layer 140, a top layer 150, a second electrode 180, and a filter layer 170. The substrate 120 is provided on one side of the first electrode 110. The light absorption layer 140 is provided on the side of the substrate 120 away from the first electrode 110. The top layer 150 is provided on the side of the light absorption layer 140 away from the substrate 120.The second electrode 180 is in contact with the topmost layer 150 and is provided on the side away from the light absorption layer 140 of the topmost layer 150. The filter layer 170 is provided on the side away from the substrate 120 of the light absorption layer 140 and is located on the side closer to the topmost layer 150 of the second electrode 180. The filter layer 170 is used to filter signals with a wavelength less than 1300 nm and transmit detection signals with a wavelength of 1300 nm or more to reach the light absorption layer 140.

[0022] In the schematic diagram of this embodiment, an example is shown in which the filter layer 170 is provided on the surface of the topmost layer 150 away from the light absorption layer 140.

[0023] The shape of the first electrode 110 may be circular, elliptical, etc., but is not limited thereto and is not limited in this embodiment. The material of the first electrode 110 may be gold (Au), but is not limited thereto. The first electrode 110 includes three sequentially stacked first sub-conductive layers. The material of the first layer of the three first sub-conductive layers is gold-germanium (AuGe), the material of the second layer of the three first sub-conductive layers is nickel (Ni), and the material of the third layer of the three first sub-conductive layers is gold (Au). The first layer of the three first sub-conductive layers is in direct contact with the substrate 120, the second layer of the three first sub-conductive layers is located between the first layer and the third layer, and the third layer is farther from the first layer than the second layer. When the first electrode 110 includes three first sub-conductive layers, the material of the first layer of the three first sub-conductive layers is gold-germanium (AuGe), the material of the second layer of the three first sub-conductive layers is nickel (Ni), and the material of the third layer of the three first sub-conductive layers is gold (Au), the contact resistance between the first electrode 110 and the substrate 120 is relatively small. In other words, an ohmic contact is formed between the first electrode 110 and the substrate 120, so that the contact resistance is relatively small. The first electrode 110 can be fabricated on the back surface (viewing angle shown in the figure) of the substrate 120 using an electron beam evaporation method or a thermal evaporation method. In this embodiment, since the first electrode 110 is a negative electrode, it is also called the negative electrode of the chip or the negative electrode of the chip.

[0024] The thickness range of the first electrode 110 is 2000 Å to 3000 Å. For example, the thickness of the first electrode 110 may be 2000 Å, or 2100 Å, or 2200 Å, or 2300 Å, or 2400 Å, or 2500 Å, or 2600 Å, or 2700 Å, or 2800 Å, or 2900 Å, or 3000 Å. As can be understood, the thickness of the first electrode 110 may be other numerical values except the above values, as long as the thickness range of the first electrode 110 is 2000 Å to 3000 Å. If the thickness of the first electrode 110 is less than 2000 Å, the contact resistance between the first electrode 110 and the substrate 120 is relatively large, and the performance of the photodetector chip 100 deteriorates. If the thickness of the first electrode 110 exceeds 3000 Å, the thickness of the photodetector chip 100 is relatively thick, which is disadvantageous for the weight reduction of the photodetector chip 100, and also increases the cost of the photodetector chip 100. The fact that the thickness range of the first electrode 110 in the photodetector chip 100 provided by the embodiment of the present application is 2000 Å to 3000 Å can, on the one hand, make the contact resistance between the first electrode 110 and the substrate 120 in the photodetector chip 100 relatively small, and on the other hand, can reduce the cost of the photodetector 100 and make the photodetector 100 thinner.

[0025] The substrate 120 is the base of the photodetector chip 100 and is used to place other film layers in the photodetector chip 100. The substrate 120 is provided on one side of the first electrode 110. Specifically, the substrate 120 is provided on the surface of the first electrode 110. Since the first electrode 110 is usually fabricated and formed on the substrate 120, the relationship between the substrate 120 and the first electrode 110 can be regarded as the first electrode 110 being located on the surface of the substrate 120. Usually, the first electrode 110 is provided on the entire back surface (viewing angle in the figure) of the substrate 120. In this embodiment, the material of the substrate 120 is InP. In other words, the substrate 120 is an InP substrate. The thickness of the substrate 120 is usually 350 nm. Due to the tolerance of the substrate 120 during manufacturing, etc., the thickness range of the substrate 120 is 350 nm ± 10 nm. In other words, the thickness of the substrate 120 is (350 - 10) nm to (350 + 10) nm. The substrate 120 can be fabricated by the liquid crystal pulling method, but is not limited thereto.

[0026] The light absorption layer 140, also called a photoelectric conversion layer, is used to convert the absorbed light energy into electrical energy. In this embodiment, the light absorption layer 140 receives a detection signal and is used to convert the detection signal into an electrical signal. In this embodiment, the light absorption layer 140 contains InGaAs. In other words, the light absorption layer 140 is an InGaAs light absorption layer. The light absorption layer 140 is provided on the side away from the first electrode 110 of the substrate 120.

[0027] The light absorption layer 140 is provided on the side away from the first electrode 110 of the substrate 120. Specifically, the light absorption layer 140 may be directly provided on the surface away from the first electrode 110 of the substrate 120, or there may be other film layers between the light absorption layer 140 and the substrate 120, and the light absorption layer 140 may not be directly provided on the surface away from the first electrode 110 of the substrate 120.

[0028] Generally, according to the characteristics of the InGaAs material, the InGaAs material has a relatively high responsivity to light with a wavelength greater than 1300 nm (for example, 1310 nm). However, the InGaAs material can absorb light with a wavelength of 750 nm or less, and the response of the InGaAs material to light with a wavelength of 750 nm or less is usually about 0.1 A / W, and the requirement that the responsivity is less than 0.02 A / W cannot be achieved.

[0029] In this embodiment, a filter layer 170 is provided on the photodetector chip 100. The filter layer 170 is provided on the side of the light absorption layer 140 away from the substrate 120 and is located on the side close to the top layer 150 of the second electrode 180. The filter layer 170 is used to filter signals of light with a wavelength less than 1300 nm (for example, visible light with a wavelength less than 750 nm). Thereby, the portion of light with a wavelength less than 1300 nm that enters the light absorption layer 140 is reduced or even eliminated. Therefore, for light with a wavelength less than 1300 nm (for example, visible light with a wavelength less than 750 nm), the responsivity of the light absorption layer 140 in the photodetector chip 100 according to this embodiment is small (for example, less than 0.02 A / W). When the photodetector chip 100 is applied to a distance sensor, the detection distance becomes accurate.

[0030] The thickness of the light absorption layer 140 is 1.0 μm to 3.0 μm. For example, the thickness of the light absorption layer 140 is 1.0 μm, or 1.5 μm, or 2.0 μm, or 2.5 μm, or 3.0 μm. As can be understood, the thickness of the light absorption layer 140 may be other values except the above examples, as long as the thickness of the light absorption layer 140 is 1.0 μm to 3.0 μm. When the thickness of the light absorption layer 140 is less than 1.0 μm, the absorption of the light absorption layer 140 for the detection signal incident on the light absorption layer 140 is insufficient, and some detection signals (light energy) cannot be converted into electrical signals. When the thickness of the light absorption layer 140 is greater than 3.0 μm, the weight reduction of the photodetector chip 100 is insufficient and the manufacturing cost is also high. Since the thickness of the light absorption layer 140 in the photodetector chip 100 provided by the embodiment of the present application is 1.0 μm to 3.0 μm, on the one hand, the light absorption layer 140 has a good effect of absorbing the incident detection signal and converting it into an electrical signal, and on the other hand, the photodetector chip 100 can be made thinner and the manufacturing cost of the photodetector chip 100 can be reduced.

[0031] The light absorption layer 140 can be manufactured by a Metal-organic Chemical Vapor Deposition (MOCVD) process or a Molecular Beam Epitaxy (MBE) process.

[0032] The top layer 150 is also called a cap layer. The top layer 150 is provided on the side away from the substrate 120 of the light absorption layer 140. In this embodiment, the top layer 150 is provided on the surface away from the substrate 120 of the light absorption layer 140. The top layer 150 is used to reduce the dark current of the photodetector chip 100. The material of the top layer 150 is InP.

[0033] The material of the light absorption layer 140 is InGaAs. Since the band gap of the InGaAs material is relatively small, the dark current of the photodetector chip 100 is relatively large, and the noise of the photodetector chip 100 is relatively large. The material of the top layer 150 is InP. Since the band gap of the top layer is relatively large, this reduces the dark current of the photodetector chip 100. As can be seen from this, the band gap of the top layer 150 provided by the embodiment of the present application is larger than the band gap of the light absorption layer 140, and the top layer 150 can reduce the dark current of the photodetector chip 100.

[0034] The thickness of the top layer 150 is 0.5 μm to 1.0 μm. For example, the thickness of the top layer 150 is 0.5 μm, or 0.6 μm, or 0.7 μm, or 0.8 μm, or 0.9 μm, or 1.0 μm. As can be understood, the thickness of the top layer 150 may be other numerical values except for the above examples, as long as the thickness of the top layer 150 is 0.5 μm to 1.0 μm. When the thickness of the top layer 150 is less than 0.5 μm, the dark current of the photodetector chip 100 is relatively large, and thus the noise of the photodetector chip 100 is large. When the thickness of the top layer 150 is greater than 1.0 μm, this is a great inhibition to the subsequent diffusion of Zn to form the active region. The fact that the thickness of the top layer 150 in the photodetector chip 100 provided by the embodiments of the present application is 0.5 μm to 1.0 μm can achieve both the reduction of the dark current and noise of the photodetector chip 100 and the reduction of the complexity in manufacturing the subsequent active region. Note that the noise of the photodetector chip 100 refers to, for the photodetector chip 100, other electrical signals except for the electrical signal obtained by the photodetector chip 100 receiving a detection signal and converting it based on the detection signal.

[0035] The top layer 150 can be manufactured by a metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) process.

[0036] The second electrode 180 is in contact with the uppermost layer 150, and the second electrode 180 is provided on the side away from the light absorption layer 140 of the uppermost layer 150. The shape of the second electrode 180 will be described in detail later. The second electrode 180 may be a three-layer second sub-conductive layer. The material of the first layer of the three-layer second sub-conductive layer is titanium (Ti), the material of the second layer is platinum (Pt), and the material of the third layer is gold (Au). The first layer of the three-layer second sub-conductive layer is closer to the substrate 120 than the second layer and the third layer, the second layer is located between the first layer and the third layer, and the third layer is farther from the substrate 120 than the second layer and the first layer. Due to the above configuration of the second electrode 180, the contact resistance between the second electrode 180 and the film layer with which the second electrode 180 is in contact is relatively small. In other words, an ohmic contact is formed between the second electrode 180 and the film layer with which the second electrode 180 is in contact, so that the contact resistance is relatively small. The second electrode 180 can be manufactured using an electron beam evaporation method, but is not limited thereto. In this embodiment, since the second electrode 180 is a positive electrode, it is also called the positive electrode of the chip or the positive electrode of the chip.

[0037] The thickness range of the second electrode 180 is from 0.1 μm to 2.0 μm. For example, the thickness of the second electrode 180 is 0.1 μm, or 0.2 μm, or 0.3 μm, or 0.4 μm, or 0.5 μm, or 0.6 μm, or 0.7 μm, or 0.8 μm, or 0.9 μm, or 1.0 μm, or 1.1 μm, or 1.2 μm, or 1.3 μm, or 1.4 μm, or 1.5 μm, or 1.6 μm, or 1.7 μm, or 1.8 μm, or 1.9 μm, or 2.0 μm. As can be understood, the thickness of the second electrode 180 may be other values except for the above examples, as long as the thickness range of the second electrode 180 is from 0.1 μm to 2.0 μm. When the thickness of the second electrode 180 is less than 0.1 μm, the contact resistance between the second electrode 180 and the film layer in contact with the second electrode 180 is relatively large, so the performance of the photodetector chip 100 is relatively poor. When the thickness of the second electrode 180 is greater than 2.0 μm, since the thickness of the photodetector chip 100 is relatively large, this is disadvantageous for the weight reduction of the photodetector chip 100, and also the cost of the photodetector chip 100 becomes relatively high. The fact that the thickness range of the second electrode 180 in the photodetector chip 100 provided by the embodiments of the present application is from 0.1 μm to 2.0 μm can, on the one hand, make the contact resistance between the second electrode 180 in the photodetector chip 100 and the film layer in contact with the second electrode 180 relatively small, and on the other hand, can reduce the cost of the photodetector 100 and make the photodetector 100 thinner.

[0038] The filter layer 170 is provided on the side of the light absorption layer 140 away from the substrate 120 and is located on the side close to the uppermost layer 150 of the second electrode 180. In other words, the filter layer 170 is located between the light absorption layer 140 and the second electrode 180. Before the light enters the light absorption layer 140, it first enters the filter layer 170. In other words, when the light enters the photodetector chip 100, after passing through the filter layer 170, it enters the light absorption layer 140. The filter layer 170 is used to filter signals with a wavelength less than 1300 nm and transmit detection signals with a wavelength of 1300 nm or more. Therefore, after passing through the filtering action of the filter layer 170, light rays with a wavelength less than 1300 nm are filtered, and light rays with a wavelength of 1300 nm or more can pass through and enter the light absorption layer 140.

[0039] In one embodiment, the InGaAsP in the filter layer 170 is In 1-x Ga x As y P 1-y satisfies, where x = 0.2143 and y = 0.4655. Thus, 1 - x = 0.7857 and 1 - y = 0.5345. When the InGaAsP in the filter layer 170 is In 1-x Ga x As y P 1-y satisfies, where x = 0.2143 and y = 0.4655, the filter layer 170 has a relatively good filtering effect on signals with wavelengths less than 1300 nm.

[0040] Next, the operating principle of the photodetector chip 100 will be described. When the photodetector chip 100 is applied to the distance sensor 10, the distance sensor 10 further includes a transmitting chip 300 for transmitting a detection signal (with a wavelength of 1300 nm or more, for example, 1310 nm). When the detection signal reaches the target object, it is reflected by the target object. The photodetector chip 100 receives the detection signal reflected by the target object, and ambient light in the external environment (visible light with a wavelength less than 1300 nm and usually less than 750 nm) also enters the photodetector chip 100. Therefore, the optical signal entering the photodetector chip 100 includes an ambient light signal in addition to the detection signal. In other words, the incident light incident on the photodetector chip 100 includes a detection signal and an ambient light signal. The photodetector chip 100 provided in the embodiment of the present application includes a filter layer 170. The filter layer 170 blocks the passage of signals with a wavelength less than 1300 nm and allows the detection signal with a wavelength of 1300 nm or more to pass before the optical signal enters the light absorption layer 140. Since the wavelength of the ambient light is less than 1300 nm and the ambient light is usually visible light with a wavelength less than 750 nm, the filter layer 170 reduces and even avoids the interference of the photodetector chip 100 caused by the presence of signals with a wavelength less than 1300 nm, such as ambient light. When the photodetector chip 100 is applied to the distance sensor 10, based on the detection signal with a wavelength of 1300 nm or more absorbed by the light absorption layer 140 of the photodetector chip 100, the accuracy of determining the distance between the target object and the distance sensor 10 can be improved.

[0041] Next, the operating principle of the photodetector chip 100 will be described. When the photodetector chip 100 operates, a reverse bias voltage is applied to the photodetector chip 100. Specifically, the first electrode 110 is the negative electrode of the chip, the second electrode 180 is the positive electrode of the chip, a positive voltage is applied to the first electrode 110, and a negative voltage is applied to the second electrode 180. Therefore, a reverse bias voltage is applied to the photodetector chip 100. Since a positive voltage is applied to the first electrode 110 and a negative voltage is applied to the second electrode 180, an electric field is formed between the first electrode 110 and the second electrode 180. The detection signal enters the light absorption layer 140, and a photoelectric reaction occurs. The light absorption layer 140 converts the detection signal, which is light energy, into electrical energy, generating electrons and holes. The electrons and holes form a drift due to the electric field formed by the first electrode 110 and the second electrode 180. Specifically, the electrons flow to the second electrode 180, and the holes flow to the first electrode 110, thereby forming a sensing current.

[0042] In the schematic diagram of this embodiment, the filter layer 170 is provided on the surface of the uppermost layer 150 away from the light absorption layer 140. As can be understood, the schematic diagram of this embodiment should not be understood as a limitation of the photodetector chip 100 provided by the embodiments of this application. Since the uppermost layer 150 is located before the incident light enters the light absorption layer 140 and the filter layer 170 is located on the uppermost layer 150, signals with a wavelength less than 1300 nm can be filtered before the incident light enters the light absorption layer 140, so that there are few or no signals with a wavelength less than 1300 nm passing through the filter layer 170, and thus few or no signals with a wavelength less than 1300 nm enter the light absorption layer 140, allowing detection signals with a wavelength of 1300 nm or more to pass through. Therefore, the interference to the photodetector chip 100 caused by the presence of signals with a wavelength less than 1300 nm, such as ambient light, can be reduced and further avoided. When the photodetector chip 100 is applied to the distance sensor 10, detection signals with a wavelength of 1300 nm or more can enter the light absorption layer 140, and based on the detection signals with a wavelength of 1300 nm or more absorbed by the light absorption layer 140 of the photodetector chip 100, the accuracy of determining the distance between the target object and the distance sensor 10 can be improved.

[0043] Furthermore, since the filter layer 170 is provided on the surface away from the light absorption layer 140 of the top layer 150, even if a part of the signal with a wavelength less than 1300 nm in the incident light passes through the filter layer 170, a part of the signal with a wavelength less than 1300 nm in the incident light first enters the top layer 150 before entering the light absorption layer 140. The top layer 150 also absorbs the signal with a wavelength less than 1300 nm, thereby further reducing the signal with a wavelength less than 1300 nm entering the light absorption layer 140, and further avoiding the signal with a wavelength less than 1300 nm from entering the light absorption layer 140. Therefore, the interference to the photodetector chip 100 caused by the presence of signals with wavelengths less than 1300 nm, such as ambient light, can be reduced and further avoided. When the photodetector chip 100 is applied to the distance sensor 10, the detection signal with a wavelength of 1300 nm or more can enter the light absorption layer 140, and based on the detection signal with a wavelength of 1300 nm or more absorbed by the light absorption layer 140 of the photodetector chip 100, the accuracy of determining the distance between the target object and the distance sensor 10 can be further improved.

[0044] Referring to FIGS. 4 and 6 together, FIG. 6 is a cross-sectional schematic view along the line B-B of the photodetector chip in FIG. 4 in another embodiment. The photodetector chip 100 includes a first electrode 110, a substrate 120, a light absorption layer 140, a top layer 150, a second electrode 180, and a filter layer 170. The substrate 120 is provided on one side of the first electrode 110. The light absorption layer 140 includes InGaAs and is provided on the side away from the first electrode 110 of the substrate 120. The top layer 150 is provided on the side away from the substrate 120 of the light absorption layer 140. The second electrode 180 is in contact with the top layer 150 and is provided on the side away from the light absorption layer 140 of the top layer 150. The filter layer 170 is provided on the side away from the substrate 120 of the light absorption layer 140 and is located on the side close to the top layer 150 of the second electrode 180. The filter layer 170 is used to filter signals with wavelengths less than 1300 nm and transmit detection signals with wavelengths of 1300 nm or more.

[0045] In the schematic diagram of this embodiment, an example is shown in which the filter layer 170 is provided between the top layer 150 and the light absorption layer 140.

[0046] The photodetector provided by this embodiment has basically the same structure as the photodetector provided by the previous embodiment, and is different in terms of the position of the filter layer 170 in the two embodiments. In the previous embodiment, the filter layer 170 is provided on the surface of the top layer 150 that is away from the light absorption layer 140. In contrast, in this embodiment, the filter layer 170 is provided between the top layer 150 and the light absorption layer 140.

[0047] The filter layer 170 is provided between the top layer 150 and the light absorption layer 140. In this embodiment, one surface of the filter layer 170 is provided on the surface of the light absorption layer 140 that is away from the substrate 120, and the top layer 150 is provided on the other surface of the filter layer 170. The other surface of the filter layer 170 is two surfaces that are opposite to one surface of the filter layer 170.

[0048] Since the filter layer 170 is provided between the top layer 150 and the light absorption layer 140, incident light first enters the filter layer 170 before entering the light absorption layer 140. The filter layer 170 can filter signals with a wavelength less than 1300 nm, so that there are few or no signals with a wavelength less than 1300 nm passing through the filter layer 170, and thus there are few or no signals with a wavelength less than 1300 nm entering the light absorption layer 140, and detection signals with a wavelength of 1300 nm or more are passed through. Therefore, the interference to the photodetector chip 100 caused by the presence of signals with a wavelength less than 1300 nm, such as ambient light, can be reduced and further avoided. When the photodetector chip 100 is applied to the distance sensor 10, detection signals with a wavelength of 1300 nm or more can enter the light absorption layer 140, and based on the detection signals with a wavelength of 1300 nm or more absorbed by the light absorption layer 140 of the photodetector chip 100, the accuracy of determining the distance between the target object and the distance sensor 10 can be improved.

[0049] The first electrode 110 is a negative electrode, the second electrode 180 is a positive electrode, the substrate 120 is an InP substrate 120, the light absorption layer 140 is an InGaAs layer, and the filter layer 170 is an InGaAsP layer.

[0050] The light absorption layer 140 is an InGaAs layer. In other words, the material of the light absorption layer 140 is InGaAs material. Therefore, the light absorption layer 140 is also called an InGaAs light absorption layer 140, and the photodetector chip 100 is also called a photodetector chip 100 made of InGaAs material. According to the characteristics of the InGaAs material, since the InGaAs material has a relatively high responsivity to light with a wavelength greater than 1300 nm (for example, 1310 nm), the photodetector chip 100 has good responsivity.

[0051] The filter layer 170 is an InGaAsP layer. In other words, the material of the filter layer 170 is InGaAsP material. Therefore, the filter layer 170 is also called an InGaAsP filter layer. Since the filter layer 170 is an InGaAsP layer, it can have a good absorption effect on light rays with a wavelength of 1300 nm or less.

[0052] In one embodiment, the thickness d1 of the filter layer 170 satisfies 0.5 μm ≤ d1 ≤ 3.0 μm.

[0053] When the filter layer 170 is an InGaAsP layer, InGaAsP has a good absorption effect on light rays with a wavelength of less than 1300 nm. However, when the thickness d1 of the filter layer 170 is less than 0.5 μm, since the filter layer 170 is thin, the filter layer 170 cannot absorb many light rays with a wavelength of less than 1300 nm, and some light rays with a wavelength of less than 1300 nm enter the light absorption layer 140, and consequently, the operation of the light absorption layer 140 based on a signal with a wavelength of 1300 nm or more (for example, 1310 nm) is disturbed. The thicker the filter layer 170, the better the blocking and preventing effects on light rays with a wavelength of less than 1300 nm. However, the thicker the filter layer 170, the greater the overall thickness of the photodetector chip 100, and consequently, it is disadvantageous for reducing the size and weight of the photodetector chip 100. Summing up the above, the thickness d1 of the filter layer 170 in the photodetector chip 100 provided by the embodiments of the present application satisfies 0.5 μm ≤ d1 ≤ 3.0 μm, whereby the blocking and preventing effects of the filter layer 170 on light rays with a wavelength of less than 1300 nm and the reduction of the size and weight of the photodetector chip 100 can be achieved simultaneously.

[0054] The thickness d1 of the filter layer 170 satisfies 0.5 μm ≤ d1 ≤ 3.0 μm. Specifically, the thickness d1 of the filter layer 170 may be 0.5 μm, or 0.6 μm, or 0.7 μm, or 0.8 μm, or 0.9 μm, or 1.0 μm, or 1.1 μm, or 1.2 μm, or 1.3 μm, or 1.4 μm, or 1.5 μm, or 1.6 μm, or 1.7 μm, or 1.8 μm, or 1.9 μm, or 2.0 μm, or 2.1 μm, or 2.2 μm, or 2.3 μm, or 2.4 μm, or 2.5 μm, or 2.6 μm, or 2.7 μm, or 2.8 μm, or 2.9 μm, or 3.0 μm. As can be understood, the thickness d1 of the filter layer 170 may be other numerical values except for the above examples, as long as the thickness d1 of the filter layer 170 satisfies 0.5 μm ≤ d1 ≤ 3.0 μm.

[0055] Furthermore, in one embodiment, the thickness d1 of the filter layer 170 satisfies 0.5 μm ≤ d1 ≤ 1.0 μm.

[0056] When the filter layer 170 is an InGaAsP layer, InGaAsP has a good absorption effect on light rays with wavelengths less than 1300 nm, but when the thickness d1 of the filter layer 170 is less than 0.5 μm, the filter layer 170 is thin, so the filter layer 170 cannot absorb much light rays with wavelengths less than 1300 nm, and some light rays with wavelengths less than 1300 nm enter the light absorption layer 140, which in turn interferes with the operation of the light absorption layer 140 based on a signal with a wavelength of 1300 nm or more (e.g., 1310 nm). The thicker the filter layer 170, the better the blocking and blocking effect on light rays with wavelengths less than 1300 nm. However, the thicker the filter layer 170, the larger the thickness of the entire photodetector chip 100 becomes, which is disadvantageous to the size and weight reduction of the photodetector chip 100. In addition, taking into consideration the manufacturing difficulty and costs such as time when the thickness is large, the thickness d1 of the filter layer 170 satisfies 0.5 μm≦d1≦1.0 μm. In summary, the thickness d1 of the filter layer 170 in the photodetector chip 100 provided in the embodiment of the present application satisfies 0.5 μm≦d1≦1.0 μm, thereby achieving the effect of the filter layer 170 blocking and blocking light rays with wavelengths less than 1300 nm, the weight reduction of the photodetector chip 100, and the manufacturing difficulty and costs such as time of the filter layer 170.

[0057] The thickness d1 of the filter layer 170 satisfies 0.5 μm≦d1≦1.0 μm, and specifically, the thickness d1 of the filter layer 170 may be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, or 1.0 μm. As can be understood, the thickness d1 of the filter layer 170 may be other values ​​except the above examples, as long as the thickness d1 of the filter layer 170 satisfies 0.5 μm≦d1≦1.0 μm.

[0058] Continuing to refer to FIGS. 7 and 8, FIG. 7 is a schematic diagram of the active region of the photodetector chip shown in FIG. 5, and FIG. 8 is a schematic diagram of the active region of the photodetector chip shown in FIG. 6. In one embodiment, the photodetector chip 100 has an active region 100a for transmitting a detection signal to reach the light absorption layer 140, and Zn is doped in the portions of the uppermost layer 150 and the filter layer 170 that are located in the active region 100a. Zn is doped in the portion of the light absorption layer 140 that is located in the active region 100a and is close to the second electrode 180. The thickness of the portion of the light absorption layer 140 doped with Zn (denoted as d2 in the drawing) is 0.1 to 0.2 μm.

[0059] The shape of the plan view of the active region 100a may be circular, or square, or elliptical, or another shape, but is not limited thereto, and is not limited in this embodiment.

[0060] In the photodetector chip 100 of the present embodiment, since Zn is doped in the portions of the topmost layer 150 and the filter layer 170 that are located in the active region 100a, the contact between the second electrode 180 and the light absorption layer 140 is improved. Further, since Zn is also doped in the portion of the light absorption layer 140 that is located in the active region 100a and is close to the second electrode 180, the contact between the second electrode 180 and the light absorption layer 140 can be further strengthened. The thickness of the portion of the light absorption layer 140 doped with Zn is 0.1 μm to 0.2 μm. For example, the thickness of the portion of the light absorption layer 140 doped with Zn may be 0.10 μm, or 0.12 μm, or 0.13 μm, or 0.14 μm, or 0.15 μm, or 0.16 μm, or 0.17 μm, or 0.18 μm, or 0.19 μm, or 0.20 μm, but is not limited thereto. When the thickness of the portion of the light absorption layer 140 doped with Zn is less than 0.1 μm, the improvement in the contact effect between the second electrode 180 and the light absorption layer 140 is limited, and when the thickness of the portion of the light absorption layer 140 doped with Zn is greater than 0.2 μm, it is difficult to dope Zn in the light absorption layer 140. In the embodiment of the present application, the thickness of the portion of the light absorption layer 140 doped with Zn is 0.1 μm to 0.2 μm, whereby, on the one hand, the contact effect between the second electrode 180 and the light absorption layer 140 can be improved, and on the other hand, the preparation difficulty when doping Zn can be reduced.

[0061] Referring to FIGS. 7 and 8 together, the top layer 150 includes a first diffusion portion 151 and a main body portion 152. The main body portion 152 contains a first material, and the first diffusion portion 151 contains the first material and Zn. In this embodiment, the first material is InP. The method of forming the top layer 150 may be, but is not limited to, forming a complete layer of the first material film layer on the side of the substrate 120 of the light absorption layer 140 away from the substrate 120, and then doping Zn into the portion of the first material film layer corresponding to the active region 100a, so that Zn diffuses into the first material film layer corresponding to the active region 100a to form the first diffusion portion 151. In other words, the portion of the first material film layer doped with Zn is the first diffusion portion 151, and the remaining portion of the first material film layer is the main body portion 152.

[0062] Zn is doped into the portion of the first material film layer corresponding to the active region 100a (that is, Zn is contained in the first diffusion portion 151). The second electrode 180 is provided on the side of the first diffusion portion 151 away from the light absorption layer 140, and the second electrode 180 can apply a voltage to the light absorption layer 140 relatively well through the first diffusion portion 151. Due to the above-described structural design of the top layer 150 and the second electrode 180, the photodetector chip 100 has good performance.

[0063] Referring to FIGS. 4 to 8 together, the orthographic projection of the filter layer 170 on the substrate 120 completely covers the orthographic projection of the active region 100a on the substrate 120. For ease of explanation, the orthographic projection of the filter layer 170 on the substrate 120 is named the first projection, and the orthographic projection of the active region 100a on the substrate 120 is named the second projection. The fact that the orthographic projection of the filter layer 170 on the substrate 120 completely covers the orthographic projection of the active region 100a on the substrate 120 includes that the area of the first projection is larger than the area of the second projection and the second projection is completely located within the range of the first projection, or the area of the first projection is equal to the area of the second projection and the second projection and the first projection completely overlap. In the schematic diagram of this embodiment, the case where the area of the first projection is larger than the area of the second projection and the second projection is completely located within the range of the first projection will be taken as an example for explanation.

[0064] Since the orthographic projection of the filter layer 170 onto the substrate 120 completely covers the orthographic projection of the active region 100a onto the substrate 120, when incident light enters the photodetector chip 100 through the active region 100a, all of the incident light that enters the interior of the photodetector chip 100 is incident on the filter layer 170, and signals with a wavelength of less than 1300 nm among the incident light are filtered out.

[0065] Furthermore, referring to FIGS. 7 and 8 together, or referring to FIGS. 6 and 7 together, the filter layer 170 further has a second diffusion portion 171 that at least partially faces the first diffusion portion 151. The filter layer 170 contains a second material, and the second diffusion portion 171 contains the second material and Zn. The second material is InGaAsP. The orthographic projection of the second diffusion portion 171 onto the substrate 120 completely covers the orthographic projection of the active region 100a onto the substrate 120.

[0066] In this embodiment, the filter layer 170 further has an edge portion 172 in addition to the second diffusion portion 171. The edge portion 172 is provided at the periphery of the second diffusion portion 171. The method of forming the filter layer 170 may be, but is not limited to, a method of forming a complete single-layer film layer of the second material, and then doping Zn into the portion of the film layer of the second material corresponding to the active region 100a, and Zn is diffused in the film layer of the first material corresponding to the active region 100a to form the second diffusion portion 171. In other words, the portion of the film layer of the first material doped with Zn is the second diffusion portion 171, and the remaining portion of the film layer of the first material is the edge portion 172 of the filter layer 170.

[0067] Zn is doped into the portion of the film layer of the second material corresponding to the active region 100a (that is, the second diffusion portion 171 contains Zn). The second electrode 180 can apply a voltage to the light absorption layer 140 relatively well through the first diffusion portion 151 and the second diffusion portion 171. Due to the above structural design of the filter layer 170, the photodetector chip 100 has good performance.

[0068] In this embodiment, the orthographic projection of the second diffusion portion 171 onto the substrate 120 completely covers the orthographic projection of the active region 100a onto the substrate 120. On the one hand, when incident light enters the photodetector chip 100 through the active region 100a, all the incident light entering the interior of the photodetector is incident on the second diffusion portion 171 of the filter layer 170, and signals with wavelengths less than 1300 nm among the incident light are filtered. On the other hand, the second electrode 180 can apply a voltage to the light absorption layer 140 relatively well through the first diffusion portion 151 and the second diffusion portion 171. Due to the above structural design of the filter layer 170, the photodetector chip 100 has good performance.

[0069] The photodetector chip 100 has an active region 100a for receiving a detection signal. Since the film layers (for example, the top layer 150, the contact layer 160, and the filter layer 170) located in the active region 100a and on the side away from the substrate 120 of the light absorption layer 140 are doped with Zn, the active region 100a is also called a Zn diffusion region. The active region 100a can be formed by, but is not limited to, metal-organic chemical vapor deposition (MOCVD) or a thermal diffusion process.

[0070] In one embodiment, in the photodetector chip 100, the thickness of the Zn-doped portion is the sum of the thicknesses of the top layer 150, the contact layer 160, the filter layer 170, and the doped portion of the Zn-doped light absorption layer 140. For example, in one embodiment, the thickness range of the top layer 150 is 0.5 μm to 1 μm, the thickness range of the contact layer 160 is 0.1 μm to 0.2 μm, the thickness range of the filter layer 170 is 0.5 μm to 3.0 μm, and the thickness range of the Zn-doped portion of the light absorption layer 140 is 0.1 μm to 0.2 μm. Therefore, the thickness range of the Zn-doped portion of the photodetector chip 100 is 1.2 μm to 4.4 μm. Continuing to refer to FIGS. 4 and 5, or FIGS. 6 and 7, the photodetector chip 100 further includes a buffer layer 130. The buffer layer 130 is provided between the substrate 120 and the light absorption layer 140, and the lattice matching degree between the buffer layer 130 and the light absorption layer 140 is greater than the lattice matching degree between the substrate 120 and the light absorption layer 140.

[0071] The lattice matching degree between the buffer layer 130 and the light absorption layer 140 is greater than that between the substrate 120 and the light absorption layer 140. When the lattice matching degree between the light absorption layer 140 and the substrate 120 is not good, if the light absorption layer 140 is directly formed on the substrate 120, many defects are likely to occur in the light absorption layer 140. When there are many defects in the light absorption layer 140, the response of the light absorption layer 140 to the detection signal transmitted through the filter layer 170 tends to deteriorate. In the embodiment of the present application, the buffer layer 130 is provided between the substrate 120 and the light absorption layer 140. In other words, the light absorption layer 140 is provided on the substrate 120 via the buffer layer 130. Since the lattice matching degree between the buffer layer 130 and the light absorption layer 140 is greater than that between the substrate 120 and the light absorption layer 140, if the light absorption layer 140 is formed on the buffer layer 130, defects are less likely to occur in the light absorption layer 140, and furthermore, the response of the light absorption layer 140 to the detection signal transmitted through the filter layer 170 is improved, thus improving the performance of the photodetector chip 100. Specifically, since there are many defects in the substrate 120, if the light absorption layer 140 is directly disposed on the substrate 120, the dark current of the photodetector chip 100 is large. In this embodiment, since the lattice matching degree between the buffer layer 130 and the light absorption layer 140 is greater than that between the substrate 120 and the light absorption layer 140, the buffer layer 130 can shield the defects of the substrate 120 and make the dark current of the photodetector chip 100 small.

[0072] The material of the substrate 120 is InP, and the material of the buffer layer 130 is N-InP. In other words, the substrate 120 is an InP substrate, and the buffer layer 130 is an N-InP buffer layer. N-InP refers to N-type InP, usually referring to InP material doped with Si.

[0073] Continuing to refer to FIGS. 4 to 8, the photodetector chip 100 further includes a contact layer 160. The contact layer 160 is provided on the side away from the light absorption layer 140 of the uppermost layer 150. The bandgap width of the contact layer 160 is smaller than that of the uppermost layer 150.

[0074] The material of the top layer 150 contains InP, and the material of the contact layer 160 can contain InGaAsP or InGaAs. The bandgap of the contact layer 160 is smaller than that of the top layer 150, thereby reducing the contact resistance between the second electrode 180 and the optical absorption layer 140.

[0075] The thickness range of the contact layer 160 is 0.10 μm to 0.20 μm. For example, the thickness of the contact layer 160 is 0.10 μm, or 0.12 μm, or 0.14 μm, or 0.15 μm, or 0.16 μm, or 0.18 μm, or 0.2 μm. When the thickness of the contact layer 160 is less than 0.10 μm, the contact resistance of the second electrode 180 is relatively large. When the thickness of the contact layer 160 is greater than 0.20 μm, this has an obstructive effect on the diffusion of Zn when forming the active region 100a, and there is a possibility that Zn cannot diffuse relatively uniformly into the film layer below the contact layer 160. Since the thickness of the contact layer 160 in the embodiments of the present application is 0.10 μm to 0.20 μm, on the one hand, the contact resistance of the second electrode 180 is reduced, and on the other hand, the obstruction to the diffusion of Zn is reduced, which is beneficial for Zn to diffuse uniformly into the film layer below the contact layer 160.

[0076] The contact layer 160 can be manufactured by a metalorganic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE) process.

[0077] Referring to FIGS. 7 to 8 together, as can be understood, the contact layer 160 includes a third diffusion portion 161 and a contact main body portion 162. The third diffusion portion 161 is located in the active region, the contact main body portion 162 surrounds the third diffusion portion 161, and the contact main body portion 162 is located in the non-active region. The material of the contact main body portion 162 is a third material, and the third material is InGaAs. The third diffusion portion 161 includes the third material and Zn.

[0078] Furthermore, referring to FIGS. 4 to 8 together, the photodetector chip 100 further includes a passivation layer 210. The passivation layer 210 is provided on the side away from the substrate 120 layer of the contact layer 160, and the passivation layer 210 has a through hole 220a. The through hole 220a defines the active region 100a. The thickness range of the passivation layer 210 is 0.1 μm to 2.0 μm.

[0079] The passivation layer 210 is used to reduce the dark current of the photodetector chip 100. Since the passivation layer 210 is located on the surface of the photodetector chip 100, the passivation layer 210 is also called a surface passivation layer. Since the passivation layer 210 is located on the surface of the photodetector chip 100, the passivation layer 210 also serves to protect the surface of the photodetector chip 100. The material of the passivation layer 210 may be silicon oxide (SiO2) or silicon nitride (SiNx), but is not limited thereto.

[0080] The thickness of the passivation layer 210 may be 0.1 μm, or 0.11 μm, or 0.12 μm, or 0.13 μm, or 0.14 μm, or 0.15 μm, or 0.16 μm, or 0.17 μm, or 0.18 μm, or 0.19 μm, or 2.0 μm, but is not limited thereto. As can be understood, the thickness of the passivation layer 210 may be other numerical values except the above examples, and mainly the thickness range of the passivation layer 210 only needs to satisfy 0.1 μm to 2.0 μm. When the thickness of the passivation layer 210 is less than 0.1 μm, there is a risk that when doping Zn, it is not possible to completely block Zn from entering each film layer under the passivation layer 210. When Zn enters the film layer under the passivation layer 210 through the passivation layer 210, the dark current of the photodetector chip 100 increases. When the thickness of the passivation layer 210 is greater than 0.20 μm, it is difficult to form the through hole 220a in the passivation layer 210. In the photodetector chip 100 provided according to the embodiment of the present application, since the thickness range of the passivation layer 210 is 0.1 μm to 2.0 μm, on the one hand, it can play a role in blocking when doping Zn. Specifically, it plays a role in preventing the diffusion of Zn to the portion of the film layer covered by the passivation layer 210, and on the other hand, it can reduce the difficulty of forming the through hole 220a.

[0081] Furthermore, referring also to FIGS. 4 to 8, the photodetector chip 100 provided in this embodiment further includes a transmission-increasing film 220. The transmission-increasing film 220 is provided in a transmission hole 220a. The transmission-increasing film 220 is used to reduce the reflectance of incident light, and thus increase the amount of incident light entering the interior of the photodetector chip 100. Specifically, in this embodiment, the transmission-increasing film 220 is used to give a large transmittance to the detection signal incident on the transmission-increasing film 220. The thickness of the transmission-increasing film 220 is 0.1 μm or more. In this embodiment, the range of the thickness of the transmission-increasing film 220 is 1300 / (4n) nm to 1330 / (4n) nm, where n is the refractive index of the transmission-increasing film 220. For example, the thickness of the transmission-increasing film 220 may be [1300 / (4n)] nm, or [1310 / (4n)] nm, or [1320 / (4n)] nm, or [1330 / (4n)] nm. When the thickness of the transmission-increasing film 220 is [1300 / (4n)] nm, the transmission-increasing film 220 has the largest transmittance for a detection signal of 1300 nm, and relatively small transmittances for other wavelength ranges. When the thickness of the transmission-increasing film 220 is [1310 / (4n)] nm, the transmission-increasing film 220 has the largest transmittance for a detection signal of 1310 nm, and relatively small transmittances for other wavelength ranges. When the thickness of the transmission-increasing film 220 is [1320 / (4n)] nm, the transmission-increasing film 220 has the largest transmittance for a detection signal of 1320 nm, and relatively small transmittances for other wavelength ranges. When the thickness of the transmission-increasing film 220 is [1330 / (4n)] nm, the transmission-increasing film 220 has the largest transmittance for a detection signal of 1330 nm, and relatively small transmittances for other wavelength ranges.

[0082] When the thickness of the transmission-increasing film 220 is 1300 / (4n) nm to 1330 / (4n) nm, the transmission-increasing film 220 has a relatively large transmittance for a detection signal with a wavelength of 1300 nm to 1330 nm, and a relatively small transmittance for light with a wavelength less than 1300 nm. In other words, the thickness of the transmission-increasing film 220 is 1300 / (4n) nm to 1330 / (4n) nm, and the transmission-increasing film 220 has a larger transmittance for a detection signal with a wavelength of 1300 nm to 1330 nm than for light with a wavelength less than 1300 nm.

[0083] The material for increasing the transmittance of the film 220 may be silicon oxide (SiO2) or silicon nitride (SiNx), but is not limited thereto. The manufacturing method of the transmittance-increasing film 220 may be Plasma Enhanced Chemical Vapor Deposition (PECVD), but is not limited thereto.

[0084] There is an annular gap between the periphery of the transmittance-increasing film 220 and the peripheral sidewall of the passivation layer 210 where the through hole 220a is formed. The second electrode 180 includes a first conductive part 181 and a second conductive part 182. The first conductive part 181 is located in the annular gap and is provided so as to surround the transmittance-increasing film 220. The second conductive part 182 is provided on the surface of the passivation layer 210 away from the substrate 120. The second conductive part 182 is electrically connected to the first conductive part 181.

[0085] Referring also to FIG. 4, the photodetector chip 100 further includes a labeling part 230. The labeling part 230 is provided on the passivation layer 210 and is provided at a distance from the second electrode 180.

[0086] The labeling part 230 is used for alignment in the manufacturing process of the photodetector chip 100 or for distinguishing different photodetector chips 100 as appearance parts. Since the labeling part 230 does not perform a light detection function during the operation of the photodetector chip 100, the labeling part 230 is also called a non-functional part, and the region where the labeling part 230 is located is also called a non-functional region or a labeling region.

[0087] In this embodiment, the material of the labeling part 230 is the same as that of the second electrode 180, and the labeling part 230 can be manufactured in the same manufacturing process as the second electrode 180, thereby reducing the manufacturing process.

[0088] Referring to FIGS. 4 to 8 together, the periphery of the filter layer 170 is exposed to the passivation layer 210. When manufacturing the photodetector chip 100, usually, a plurality of photodetector chips 100 are manufactured together, the plurality of photodetector chips 100 are provided at intervals, and the periphery of the filter layer 170 is exposed to the passivation layer 210 between two adjacent photodetector chips 100. After the manufacture of the plurality of photodetector chips 100 is completed, usually, a plurality of single photodetector chips 100 are formed by cutting the plurality of photodetector chips 100 at the portion where the filter layer 170 is exposed to the passivation layer 210. The peripheral region where the filter layer 170 is exposed to the passivation layer 210 is the region where the photodetector chip 100 is divided, and is also called the dividing line region.

[0089] As can be understood, the plan view of the photodetector chip 100 described in the plan view of FIG. 4 and its related embodiments does not constitute a limitation on the photodetector chip 100 provided by the embodiments of the present application. The plan view of the photodetector chip 100 may be in other forms. For example, referring to FIGS. 9 and 10 together, FIG. 9 is a plan view of a photodetector chip provided by another embodiment of the present application, and FIG. 10 is a plan view of a photodetector chip provided by a further embodiment of the present application.

[0090] Referring to FIG. 11, FIG. 11 is a schematic diagram of a distance sensor provided by one embodiment of the present application. The present application further provides a distance sensor 10 including a transmitting chip 300 and a photodetector chip 100. The transmitting chip 300 is used to emit a detection signal. For the photodetector chip 100, reference can be made to the foregoing description, and the description will not be repeated here. The filter layer 170 of the photodetector chip 100 is used to filter a signal with a wavelength less than 1300 nm and transmit a detection signal with a wavelength of 1300 nm or more.

[0091] The wavelength of the detection signal emitted from the emission chip 300 is 1300 nm or more, for example, 1310 nm. A signal with a wavelength of 1300 nm or more is a signal in the infrared wavelength range. When the detection signal emitted from the emission chip 300 is reflected by the target object, the reflected detection signal can enter the photodetector chip 100, and external ambient light can also enter the photodetector chip 100. The external ambient light is usually light with a wavelength less than 1300 nm, for example, visible light with a wavelength less than 750 nm.

[0092] The filter layer 170 in the photodetector chip 100 is used to filter signals with a wavelength less than 1300 nm and allow detection signals with a wavelength of 1300 nm or more to pass through. Therefore, it is possible to avoid signals with a wavelength less than 1300 nm from interfering with the detection signal with a wavelength of 1300 nm or more emitted from the emission chip 300. As a result, based on the detection signal with a wavelength of 1300 nm or more absorbed by the light absorption layer 140 of the photodetector chip 100, the accuracy of determining the distance between the target object and the distance sensor 10 can be improved.

[0093] In one embodiment, the distance sensor 10 has a sealing housing 500. The sealing housing 500 has a first accommodation space 510 and a second accommodation space 520 provided at intervals, a first opening 510a communicating with the first accommodation space 510, and a second opening 510b communicating with the second accommodation space 520. The first accommodation space 510 is used to accommodate the emission chip 300. The detection signal emitted from the emission chip 300 can be emitted through the first opening 510a. The detection signal emitted from the first opening 510a is reflected by the target object 2 and enters the photodetector chip 100 through the second opening 510b. The second accommodation space 520 is used to accommodate the photodetector chip 100, and the photodetector chip 100 can receive the detection signal through the second opening 510b.

[0094] Referring further to FIGS. 12 and 13, FIG. 12 is a schematic diagram of an electronic device provided by one embodiment of the present application, and FIG. 13 is a cross-sectional view of the electronic device of FIG. 12 along line C-C. The present application further provides an electronic device 1. The electronic device 1 may be a device having a distance sensing function such as a smart driving, a sweeping robot, a mobile phone, a tablet computer, a notebook computer, a handheld computer, a personal computer (PC), a personal digital assistant (PDA), a portable media player (PMP), earphones, a camera, a smart wearable device, a smart screen, a display screen, a wind power generation device, etc., but is not limited thereto.

[0095] In one embodiment, the electronic device 1 includes a display screen 30 and a distance sensor 10. The display screen 30 is an organic light emitting diode (OLED) display screen, and in another embodiment, the display screen 30 may be a liquid crystal display screen. The display screen 30 has a display area 310. The display area 310 refers to an area having a display function on the display screen 30. The distance sensor 10 is provided on one side of the display screen 30 and is provided corresponding to the display area 310 of the display screen 30. The emission chip 300 of the distance sensor 10 is used to emit a detection signal toward the display screen 30. The photodetector chip 100 of the distance sensor 10 is used to receive the detection signal transmitted through the display screen 30. The wavelength of the detection signal is 1300 nm or more.

[0096] The fact that the distance sensor 10 is provided corresponding to the display area 310 of the display screen 30 means that the orthographic projection of the distance sensor 10 onto the display screen 30 is located within the range of the display area 310. In the present embodiment, the display screen 30 may be an organic light emitting diode (OLED) display screen. When the display screen 30 is an OLED display screen, since the detection signal emitted from the emission chip 300 of the distance sensor 10 with a wavelength of 1300 nm or more can pass through the display screen 30, the distance sensor 10 is provided corresponding to the display area 310 of the display screen 30. Since the distance sensor 10 is provided corresponding to the display area 310 of the display screen 30, there is no need to provide the distance sensor 10 in the non-display area 320 of the display screen 30, and there is no need to make a hole for providing the distance sensor 10 in the non-display area 320 of the display screen 30. Therefore, the screen occupancy rate of the electronic device 1 provided in the embodiment of the present application is high.

[0097] Referring to FIG. 12, in the present embodiment, the display screen 30 further has a non-display area 320 provided at the periphery of the display area 310. The non-display area 320 is an area where the display screen 30 has no display function. As can be understood, the distance sensor 10 may be provided corresponding to the non-display area 320 of the display screen 30. The emission chip 300 of the distance sensor 10 emits a detection signal toward the display screen 30. The photodetector chip 100 of the distance sensor 10 is used to receive the detection signal that has passed through the display screen 30. The wavelength of the detection signal is 1300 nm or more. As can be understood, the display screen 30 may not have the non-display area 320, and in the present application, whether the display screen 30 has the non-display area 320 or not is not limited.

[0098] Continuing to refer to FIG. 13, the display screen 30 includes a pixel defining layer 31 and a light emitting layer 32. The pixel defining layer 31 includes a plurality of pixel opening regions 311 and a plurality of pixel defining portions 30a, and the plurality of pixel defining portions 30a surround to form the plurality of pixel opening regions 311. The light emitting layer 32 includes a plurality of light emitting units 30b provided in the plurality of pixel opening regions 311. The emission chip 300 and the photodetector chip 100 of the distance sensor 10 are provided corresponding to the same pixel defining portion 30a between two adjacent light emitting units 30b, or the emission chip 300 and the photodetector chip 100 of the distance sensor 10 are provided corresponding to a plurality of pixel defining portions 30a located in the same row or the same column.

[0099] The emission chip 300 and the photodetector chip 100 of the distance sensor 10 are provided corresponding to the same pixel limiting portion 30a between two adjacent light emitting units 30b, or the emission chip 300 and the photodetector chip 100 of the distance sensor 10 are provided corresponding to a plurality of pixel limiting portions 30a located in the same row or the same column. In this case, in the detection signal emitted from the emission chip 300, since the portion blocked by the light emitting unit 30b is small and even non-existent, the portion that can be emitted outside the display screen 30 is relatively large. Also, in the detection signal reflected by the target object, since the portion blocked by the light emitting unit 30b is small and even non-existent, the portion that can enter the photodetector chip 100 is relatively large. Thus, based on the detection signal emitted from the emission chip 300 and the detection signal reflected by the photodetector chip 100, the accuracy of the distance sensor in determining the distance between the target object and the electronic device 1 can be improved. Furthermore, when the emission chip 300 and the photodetector chip 100 of the distance sensor 10 are provided corresponding to the same pixel limiting portion 30a between two adjacent light emitting units 30b, or when the emission chip 300 and the photodetector chip 100 of the distance sensor 10 are provided corresponding to a plurality of pixel limiting portions 30a located in the same row or the same column, since the emission chip 300 and the photodetector chip 100 of the distance sensor 10 do not directly separate the light emitting unit 30b, the interference to the photodetector chip 100 when the light emitted from the light emitting unit 30b enters the photodetector chip 100 can be reduced.

[0100] In one embodiment, the material of the pixel limiting portion 30a may be an InGaAsP quaternary material. The pixel limiting portion 30a can, on the one hand, limit the pixel opening region 311, and on the other hand, transmit light rays with a wavelength of 1300 nm or more and absorb light rays with a wavelength less than 1300 nm. In this embodiment, the pixel limiting portion 30a can further block light rays with a wavelength less than 1300 nm.

[0101] Furthermore, the display screen 30 further includes a light-shielding material 30c. The light-shielding material 30c is provided at the periphery of the distance sensor 10 and seals the gap between the distance sensor 10 and the display screen 30, thereby preventing light from entering the light detector chip 100 in the distance sensor 10 through the gap between the display screen 30 and the distance sensor 10.

[0102] In the present embodiment, the display screen 30 further includes a sealing material. The sealing material is provided on the side of the light-emitting unit 30b away from the distance sensor 10 and is used to protect the light-emitting unit 30b.

[0103] As described above, the embodiments of the present application have been shown and described. However, the above embodiments are illustrative and should not be construed as limiting the present application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application. These improvements and refinements should also fall within the protection scope of the present application.

Claims

1. A photodetector chip, comprising: a first electrode, a substrate, an optical absorption layer, a top layer, a second electrode, and a filter layer; wherein the substrate is provided on one side of the first electrode; the optical absorption layer is provided on a side of the substrate away from the first electrode; the top layer is provided on a side of the optical absorption layer away from the substrate; the second electrode is in contact with the top layer and is provided on a side of the top layer away from the optical absorption layer; the filter layer is provided on a side of the optical absorption layer away from the substrate and is located on a side of the second electrode close to the top layer, and the filter layer is used to filter a signal with a wavelength less than 1300 nm and transmit a detection signal with a wavelength of 1300 nm or more to reach the optical absorption layer; A photodetector chip characterized by the above.

2. The filter layer is provided on a surface of the top layer away from the optical absorption layer, or the filter layer is provided between the top layer and the optical absorption layer. The photodetector chip according to claim 1, characterized by the above.

3. The first electrode is a negative electrode, the second electrode is a positive electrode, the substrate is an InP substrate, the optical absorption layer is an InGaAs layer, and the filter layer is an InGaAsP layer. The photodetector chip according to claim 2, characterized by the above.

4. InGaAsP in the filter layer satisfies In １－ｘ Ga ｘ As ｙ P １－ｙ and has x = 0.2143 and y = 0.4655. The photodetector chip according to claim 3, characterized by the above.

5. The thickness d1 of the filter layer satisfies 0.5 μm ≤ d1 ≤ 3.0 μm. The photodetector chip according to claim 4, characterized by the above.

6. The photodetector chip has an active region for transmitting the detection signal to reach the optical absorption layer, and Zn is doped in a portion of the top layer and the filter layer located in the active region, and Zn is doped in a portion of the optical absorption layer located in the active region and close to the second electrode, and the thickness of the portion of the optical absorption layer doped with Zn is 0.1 μm to 0.2 μm. The photodetector chip according to any one of claims 1 to 5, characterized by the above.

7. The photodetector chip further comprises a buffer layer. The buffer layer is provided between the substrate and the optical absorption layer, and the lattice matching degree between the buffer layer and the optical absorption layer is greater than the lattice matching degree between the substrate and the optical absorption layer. The photodetector chip according to claim 1, characterized by the above.

8. The photodetector chip further includes a contact layer, wherein the contact layer is provided on a side away from the uppermost light absorption layer, a portion of the contact layer located in the active region is doped with Zn, and the bandgap width of the contact layer is smaller than that of the uppermost layer. The photodetector chip according to claim 6, characterized in that.

9. The photodetector chip further includes a passivation layer and a transmission enhancement film, wherein the passivation layer is provided on a side away from the substrate of the contact layer, and the passivation layer has a through hole defining the active region. The transmission enhancement film is provided in the through hole, and there is an annular gap between the periphery of the transmission enhancement film and the peripheral side wall of the passivation layer that forms the through hole. The second electrode includes a first conductive portion and a second conductive portion. The first conductive portion is located in the annular gap and is provided so as to surround the transmission enhancement film. The second conductive portion is provided on the surface of the passivation layer away from the substrate, and the second conductive portion is electrically connected to the first conductive portion. The photodetector chip according to claim 8, characterized in that.

10. A photodetector chip, comprising a first electrode, a substrate, a light absorption layer, an uppermost layer, a contact layer, a passivation layer, a transmission enhancement film, a second electrode, and a filter layer. The substrate is provided on one side of the first electrode. The light absorption layer is an InGaAs layer, the thickness of the light absorption layer is 1.0 μm to 3.0 μm, and the light absorption layer is provided on a side away from the first electrode of the substrate. The uppermost layer is provided on a side away from the substrate of the light absorption layer. The bandgap width of the uppermost layer is larger than that of the light absorption layer, and the thickness of the uppermost layer is 0.5 μm to 1.0 μm. The contact layer is provided on a side away from the light absorption layer of the uppermost layer. The passivation layer is provided on a side away from the substrate of the contact layer. The passivation layer has a through hole defining the active region, and the thickness of the passivation layer is 0.1 μm to 2.0 μm. The transmission enhancement film is provided in the transmission hole, and there is an annular gap between the periphery of the transmission enhancement film and the peripheral side wall of the passivation layer that forms the transmission hole. The thickness of the transmission enhancement film is 1300 / (4n) nm to 1330 / (4n) nm, where n is the refractive index of the transmission enhancement film. The second electrode is in contact with the uppermost layer and is provided on the side away from the light absorption layer of the uppermost layer. The filter layer is provided on the side of the light absorption layer away from the substrate and is located on the side close to the uppermost layer of the second electrode. The filter layer is used to filter signals with a wavelength of less than 1300 nm so that the responsivity of the light absorption layer to light with a wavelength of 1300 nm or less is less than 0.02 A / W, and to transmit detection signals with a wavelength of 1300 nm or more to reach the light absorption layer. An optical detector chip characterized by the above.

11. The filter layer is provided on the surface of the uppermost layer away from the light absorption layer, or The filter layer is provided between the uppermost layer and the light absorption layer. The optical detector chip according to claim 10, characterized by the above.

12. The first electrode is a negative electrode, the second electrode is a positive electrode, the substrate is an InP substrate, and the filter layer is an InGaAsP layer. The optical detector chip according to claim 11, characterized by the above.

13. InGaAsP in the filter layer satisfies In １－ｘ Ga ｘ As ｙ P １－ｙ and x = 0.2143, y = 0.4655 The optical detector chip according to claim 12, characterized by the above.

14. The thickness d1 of the filter layer satisfies 0.5 μm ≤ d1 ≤ 3.0 μm. The optical detector chip according to claim 13, characterized by the above.

15. The optical detector chip has an active region for transmitting the detection signal to reach the light absorption layer. Zn is doped in the portions of the uppermost layer and the filter layer located in the active region. Zn is doped in the portion of the light absorption layer located in the active region and close to the second electrode. The thickness of the portion of the light absorption layer doped with Zn is 0.1 μm to 0.2 μm. The optical detector chip according to any one of claims 10 to 14, characterized by the above.

16. The optical detector chip further includes a buffer layer. The buffer layer is provided between the substrate and the light absorption layer, and the lattice matching degree between the buffer layer and the light absorption layer is greater than the lattice matching degree between the substrate and the light absorption layer. The photodetector chip according to claim 10, characterized in that...

17. A portion of the contact layer located in the active region is doped with Zn, and the bandgap of the contact layer is smaller than the bandgap of the uppermost layer. The photodetector chip according to claim 15, characterized in that...

18. The second electrode includes a first conductive portion and a second conductive portion. The first conductive portion is located within the annular gap and is provided so as to surround the transmission enhancement film. The second conductive portion is provided on the surface of the passivation layer away from the substrate, and the second conductive portion is electrically connected to the first conductive portion. The photodetector chip according to claim 17, characterized in that...

19. A distance sensor, comprising: A transmitting chip for emitting a detection signal, and a photodetector chip according to any one of claims 1 to 18. The filter layer of the photodetector chip is used to filter signals with a wavelength less than 1300 nm and transmit detection signals with a wavelength of 1300 nm or more. The distance sensor, characterized in that...

20. An electronic device, comprising: A display screen having a display area, and a distance sensor according to claim 19. The distance sensor is provided on one side of the display screen and corresponding to the display area of the display screen. The transmitting chip of the distance sensor is used to emit a detection signal toward the display screen, and the photodetector chip of the distance sensor is used to receive the detection signal transmitted through the display screen. The wavelength of the detection signal is 1300 nm or more. The electronic device, characterized in that...

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