Image sensor and electronic device

Abstract

Provided in the present application are an image sensor and an electronic device. The present application relates to the technical field of photoelectric conversion. The image sensor comprises: a semiconductor substrate and a photoelectric conversion structure, which is formed in the semiconductor substrate, wherein the semiconductor substrate has a light-incident side for receiving light. The light-incident side is provided with a first film layer, a second film layer and a third film layer that are arranged in a stacked manner, wherein the first film layer and the third film layer have electronegativity, and the first film layer and the third film layer, which have the electronegativity can induce holes, in the semiconductor substrate; the second film layer comprises silicon oxide or tantalum oxide, or has electronegativity; and the material of the second film layer is different from the material of the first film layer, and the material of the second film layer is different from the material of the third film layer. In the present application, by means of using a structure with at least two electronegative film layers, more holes can be induced at the surface of a semiconductor substrate, and a hole interface is used to allow photoelectrons to avoid defects, which are introduced by dangling bonds on the surface of the semiconductor substrate, thereby suppressing dark currents of the image sensor, and reducing the occurrence of white spots in an obtained image.

Description

Image sensor, electronic device

[0001] The present application claims priority from the Chinese patent application No. 202410639971.4 filed on May 21, 2024, and entitled "Image sensor, electronic device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of photoelectric conversion, in particular to an image sensor and an electronic device comprising the same. BACKGROUND

[0003] With the increasing richness of functions of electronic devices, image sensors are increasingly widely used in electronic devices. An image sensor receives a light signal, excites electrons and collects them, so that the image sensor can generate a corresponding electrical signal based on the light signal, realizing the conversion from the light signal to the electrical signal. Among them, the complementary metal-oxide-semiconductor (CMOS) image sensor (CIS) has the advantages of high integration, low power consumption and low generation cost, and has been widely used.

[0004] Dark current and white point are important factors affecting the performance of an image sensor. How to effectively suppress the dark current and the white point is a technical problem faced by the improvement of the performance of the image sensor. SUMMARY

[0005] The present application provides an image sensor and an electronic device comprising the same. The purpose is to suppress the dark current and weaken the white point phenomenon.

[0006] To achieve the above purpose, the embodiments of the present application adopt the following technical solutions:

[0007] On the one hand, the present application provides an image sensor, for example, the image sensor can be applied in a display device that can image.

[0008] The image sensor includes: a semiconductor substrate and a photoelectric conversion structure formed in the semiconductor substrate, such as a photodiode; the semiconductor substrate has a light-receiving side for receiving light and a back light side opposite to the light-receiving side; the image sensor can further include a plurality of film layers, the plurality of film layers include a first film layer, a second film layer and a third film layer, the first film layer, the second film layer and the third film layer are sequentially stacked on the light-receiving side of the semiconductor substrate in a direction away from the semiconductor substrate; and the first film layer and the third film layer have electronegativity, the first film layer with electronegativity can induce holes with the semiconductor substrate, and the third film layer with electronegativity can also induce holes with the semiconductor substrate; the second film layer includes silicon oxide or tantalum oxide, or is a film layer with electronegativity; the material of the second film layer is different from the material of the first film layer, and the material of the second film layer is different from the material of the third film layer.

[0009] In the image sensor provided in the present application, dangling bonds can exist on the surface of the semiconductor substrate. In the present application, at least three film layers are introduced on the surface of the semiconductor substrate. The first film layer closest to the semiconductor substrate in the three film layers has electronegativity. The first film layer with strong electronegativity can attract electrons on the surface of the semiconductor substrate, so that holes are induced at the interface between the first film layer and the surface of the semiconductor substrate. In addition, the third film layer with electronegativity can also induce holes at the surface of the semiconductor substrate.

[0010] By introducing at least two film layers with electronegativity, more holes can be induced. The holes can make photoelectrons avoid defects introduced by dangling bonds on the surface of the semiconductor substrate, so that the dark current of the image sensor can be inhibited, and the white spot phenomenon in the image can be weakened.

[0011] In an implementable manner, the material of the first film layer is the same as the material of the third film layer.

[0012] The material of the third film layer is the same as the material of the first film layer. In an implementable process, the first film layer and the third film layer can be made by using the same equipment and the same process.

[0013] In an implementable manner, the material of the first film layer is the same as the material of the third film layer, and the material of the first film layer includes aluminum oxide; the material of the third film layer includes at least one of aluminum oxide, hafnium oxide, aluminum nitride and aluminum oxynitride.

[0014] In an implementable manner, the material of the first film layer is different from the material of the third film layer.

[0015] In an implementable manner, the material of the first film layer is different from the material of the third film layer, and the material of the first film layer or the material of the third film layer includes at least one of aluminum oxide, hafnium oxide, aluminum nitride and aluminum oxynitride.

[0016] In an implementable manner, when the second film layer has electronegativity, the material of the second film layer includes at least one of aluminum oxide, hafnium oxide, aluminum nitride, aluminum oxynitride.

[0017] For example, the material of the first film layer includes aluminum oxide, the material of the second film layer includes silicon oxide, and the material of the third film layer includes aluminum oxide.

[0018] For another example, the material of the first film layer includes aluminum oxide, the material of the second film layer includes hafnium oxide, and the material of the third film layer includes aluminum oxide.

[0019] For yet another example, the material of the first film layer includes aluminum oxide, the material of the second film layer includes tantalum oxide, and the material of the third film layer includes aluminum oxide.

[0020] In an implementable manner, the plurality of film layers further include a fourth film layer, the fourth film layer is arranged on a side of the third film layer facing away from the second film layer, and the material of the fourth film layer is the same as that of the second film layer.

[0021] For example, the first film layer and the third film layer have electronegativity, and the second film layer and the fourth film layer can be selected from silicon oxide or tantalum oxide.

[0022] For another example, the first film layer, the second film layer, the third film layer, and the fourth film layer all have electronegativity, the material of the first film layer is the same as that of the third film layer, and the material of the second film layer is the same as that of the fourth film layer.

[0023] In an implementable manner, the plurality of film layers further include a fifth film layer, the fifth film layer is arranged on a side of the fourth film layer facing away from the third film layer, and the material of the fifth film layer is the same as that of the first film layer or the material of the fifth film layer is the same as that of the third film layer.

[0024] In an implementable manner, the semiconductor substrate is a P-type semiconductor layer, the P-type semiconductor layer has an N-type doped region therein, and the photoelectric conversion structure includes the P-type semiconductor layer and the N-type doped region.

[0025] In an implementable manner, the image sensor further includes: a filter and a microlens; the filter is arranged on a side of the plurality of film layers facing away from the semiconductor substrate; and the microlens is arranged on a side of the filter facing away from the plurality of film layers.

[0026] The image sensor thus formed can be referred to as a back-illuminated image sensor.

[0027] In an implementable manner, the image sensor chip includes a pixel region and a logic region surrounding the pixel region, and the photoelectric conversion structure is arranged in the pixel region.

[0028] That is, the pixel region and the logic region are integrated in one chip in the present application.

[0029] In another aspect, the present application also provides an electronic device, which can include a circuit board, and the image sensor in any of the above implementations, the image sensor being electrically connected with the circuit board.

[0030] In the image sensor of the electronic device provided by the present application, the first film layer and the second film layer, and the third film layer are introduced on the light-incident side of the semiconductor substrate, and at least the first film layer and the third film layer have electronegativity, so that holes are induced at the interface between the first film layer and the surface of the semiconductor substrate. In this way, photoelectrons can avoid defects introduced by dangling bonds on the surface of the semiconductor substrate, the dark current of the image sensor can be inhibited, the white spot phenomenon of the image can be weakened, and the imaging quality of the electronic device can be optimized.

[0031] In an implementable manner, the electronic device further includes a logic chip, and the logic chip is arranged in a three-dimensional stack with the image sensor.

[0032] In another aspect, the present application also provides a preparation method of an image sensor, which includes:

[0033] forming a photoelectric conversion structure in a semiconductor substrate;

[0034] forming a first film layer, a second film layer and a third film layer on the light-incident side of the semiconductor substrate in sequence; the first film layer and the third film layer have electronegativity, the second film layer includes silicon oxide or tantalum oxide, or has electronegativity, the material of the second film layer is different from the material of the first film layer, and the material of the second film layer is different from the material of the third film layer.

[0035] When the image sensor is prepared by using the method, the first film layer and the third film layer with electronegativity are formed on the light-incident side of the semiconductor substrate, and holes can be induced between the first film layer and the semiconductor substrate and between the third film layer and the semiconductor substrate. In this way, photoelectrons can avoid defects introduced by dangling bonds on the surface of the semiconductor substrate, and the dark current can be inhibited.

[0036] In an implementable manner, the material of the first film layer is the same as the material of the third film layer; or, the material of the first film layer is different from the material of the third film layer.

[0037] In an implementable manner, the material of the first film layer or the material of the third film layer includes at least one of aluminum oxide, hafnium oxide, aluminum nitride, and aluminum oxynitride.

[0038] In an implementable manner, the material of the second film layer with electronegativity includes at least one of aluminum oxide, hafnium oxide, aluminum nitride, and aluminum oxynitride.

[0039] In an implementable manner, after the third film layer is formed, the preparation method further includes:

[0040] A fourth film layer is formed on the third film layer, and the material of the fourth film layer is the same as that of the second film layer. BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 is a structural diagram of an electronic device according to an embodiment of the present application;

[0042] FIG. 2 is an exploded structural diagram of an electronic device according to an embodiment of the present application;

[0043] FIG. 3 is an exploded structural diagram of a camera module of an electronic device according to an embodiment of the present application;

[0044] FIG. 4 is a structural diagram of an image sensor according to an embodiment of the present application;

[0045] FIG. 5 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0046] FIG. 6 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0047] FIG. 7 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0048] FIG. 8 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0049] FIG. 9 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0050] FIG. 10 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0051] FIG. 11 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0052] FIG. 12 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0053] FIG. 13 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0054] FIG. 14 is a partial structural diagram of an image sensor according to an embodiment of the present application;

[0055] FIG. 15 is a flow chart of a method for manufacturing an image sensor according to an embodiment of the present application;

[0056] FIGS. 16A to 16F are structural diagrams of respective steps in a method for manufacturing an image sensor according to an embodiment of the present application;

[0057] FIG. 17 is a structural diagram of an integration method of an image sensor according to an embodiment of the present application;

[0058] FIGS. 18 and 19 are structural schematic diagrams of an integrated manner of an image sensor provided in embodiments of the present application. DETAILED DESCRIPTION

[0059] An image sensor, such as a CMOS image sensor, utilizes the photoelectric effect of a semiconductor material to convert a light signal into an electrical signal, thereby realizing the capture and conversion of an image. The core component of an image sensor is a photodiode, which completes photoelectric conversion by receiving light and generating electric charges. These generated electric charges are further processed, such as integration, amplification, and digitization, to form a digital image.

[0060] For example, in an electronic device, the electronic device can be a mobile phone, a tablet personal computer, a laptop computer, a personal digital assistant (PDA), a camera, a personal computer, a notebook computer, a vehicle-mounted device, a wearable device, augmented reality (AR) glasses, an AR helmet, virtual reality (VR) glasses, or a VR helmet, and the like, which are devices with a camera module. The electronic device of the embodiment shown in FIG. 1 is described by taking a mobile phone as an example.

[0061] FIG. 1 shows a schematic diagram of the external structure of a mobile phone 1000 provided in embodiments of the present application, and FIG. 2 is a schematic diagram of the exploded structure of the mobile phone 1000 provided in embodiments of the present application. In combination with FIGS. 1 and 2, the mobile phone 1000 includes a housing 100, the housing 100 includes a first housing 101 and a second housing 102 that are coupled together and form a space inside, a window 1021 is formed on the second housing 102, a camera cover plate 200 covers the window 1021, a camera module 400 is arranged in the housing 100, and the camera module 400 can be arranged on a bearing plate 500 located in the housing 100; and the camera cover plate 200 has a light-transmitting window 300, and light passing through the light-transmitting window 300 can be projected to the camera module 400 to be received by the camera module 400.

[0062] In the camera module 400, as shown in FIG. 3, the camera module 400 can include a lens 401, a filter 402, and an image sensor 403. The filter 402 is arranged on the light exit side of the lens 401, and the image sensor 403 is arranged on the light exit side of the filter 402.

[0063] For example, the filter 402 can be an infrared filter that filters out infrared light and transmits visible light. Alternatively, for another example, the filter 402 can be a dual-bandpass filter that transmits wavelengths in two ranges of the ambient light, such as visible light and infrared light, or visible light and ultraviolet light, or ultraviolet light and infrared light, and so on.

[0064] FIG. 4 illustrates a structure of an image sensor, which is a back side illumination (BSI) image sensor. The image sensor 403 can include a microlens 101, a filter 102, a photoelectric conversion device layer 103, and a wiring layer 104. The filter 102 is located on the light exit side of the microlens 101.

[0065] In the back side illumination image sensor shown in FIG. 4, the photoelectric conversion device layer 103 is located between the filter 102 and the wiring layer 104. The wiring layer 104 can interconnect devices in the photoelectric conversion device layer 103 to form a circuit structure.

[0066] Continuing to FIG. 4, light can be received by the photoelectric conversion device layer 103 after passing through the microlens 101 and the filter 102, which can improve photoelectric conversion efficiency.

[0067] The photoelectric conversion device layer 103 includes a plurality of pixel structures, each of which can serve as a pixel of the image sensor. For example, the plurality of pixel structures can be arranged in a Bayer array.

[0068] The filter 102 can filter colors of light from the microlens 101 so that the image sensor can output a color image. For example, the filter 102 includes a color filter (CF). Colors of light filtered by adjacent pixel structures can include at least three primary colors, such as red (R), green (G), and blue (B).

[0069] FIG. 5 illustrates a structure of the photoelectric conversion device layer 103 in an image sensor according to an embodiment of the present disclosure. The photoelectric conversion device layer 103 includes a semiconductor substrate in which a photoelectric conversion structure is integrated, such as a photodiode.

[0070] In some examples, as shown in FIG. 5, the semiconductor substrate includes a P-type semiconductor substrate that is doped with P-type impurities, and the P-type semiconductor substrate has an N-type doped region therein. The P-type semiconductor substrate and the N-type doped region form a PN junction, which forms a photodiode for photoelectric conversion.

[0071] In some other examples, as shown in FIG. 6, the semiconductor substrate includes a P-type semiconductor substrate having an N-type doped region therein, the P-type semiconductor substrate and the N-type doped region forming a PN junction. In addition, a P+ heavy doping is introduced in the N-type doped region of the photodiode PD, and the introduction of the P+ heavy doping suppresses the dark current generated by the defects of the Si and SiO2 lattice mismatch on the surface of the photodiode PD.

[0072] FIGS. 5 and 6 exemplarily show two photodiode structures, and the present application includes the examples of FIGS. 5 and 6, but is not limited to these photovoltaic conversion structures.

[0073] As shown in FIGS. 5 and 6, in the image sensor, a plurality of photodiodes can be integrated, and the plurality of photodiodes can be arranged in an array, and a shallow trench isolation region can be arranged between some of the photodiodes to suppress the mutual interference between the photodiodes.

[0074] Continuing to see FIGS. 5 and 6, the semiconductor substrate has a light-incident side for receiving light, and a back light side opposite to the light-incident side. The filter 102 and the microlens 101 shown in FIG. 4 are arranged on the light-incident side.

[0075] When the light passes through the microlens 101 and the filter 102 and is received by the photodiode for photovoltaic conversion, a dark current can occur on the light-incident side of the semiconductor substrate.

[0076] In order to suppress the dark current on the light-incident side of the image sensor, some process structures that can be implemented are given in the embodiments of the present application.

[0077] For example, in FIGS. 5 and 6, a first film layer, a second film layer, and a third film layer are arranged on the light-incident side of the semiconductor substrate, the first film layer is stacked on the semiconductor substrate, the second film layer is stacked on the first film layer, and the third film layer is stacked on the second film layer. The first film layer and the third film layer can be passivation layers made of high dielectric material (High-K).

[0078] The first film layer and the third film layer both have electronegativity, which can be understood as the ability of an atom of an element to attract bonding electrons in a molecule. The greater the electronegativity, the stronger the ability to attract electrons.

[0079] As shown in FIGS. 5 and 6, since the first film layer has electronegativity, it can attract the electrons on the surface of the semiconductor substrate, and holes are induced on the surface of the semiconductor substrate.

[0080] In addition, the third film layer also has electronegativity, and the third film layer can also attract the electrons on the surface of the semiconductor substrate. Under the joint action of the third film layer and the first film layer, more holes can be induced on the surface of the semiconductor substrate.

[0081] In some scenarios, the surface of the light-in side of the semiconductor substrate has dangling bonds, and the application introduces a first film layer and a third film layer with electronegativity, and uses the joint action of the first film layer and the third film layer to induce more holes on the surface of the semiconductor substrate, so that photoelectrons avoid defects introduced by dangling bonds on the surface of the semiconductor substrate, thereby inhibiting dark current.

[0082] In addition, when the structure is applied in the camera module of an electronic device, it can also weaken the imaging quality and the risk of white spots appearing in the imaging, thereby improving the imaging quality.

[0083] The first film layer can be selected from at least one of aluminum oxide AlO, hafnium oxide HfO, aluminum nitride AlN, and aluminum oxynitride AlON; and the third film layer can also be selected from at least one of aluminum oxide AlO, hafnium oxide HfO, aluminum nitride AlN, and aluminum oxynitride AlON.

[0084] In some examples, the materials of the first film layer and the third film layer can be the same, for example, in the example of FIG. 7, the first film layer and the third film layer can both be aluminum oxide AlO layers.

[0085] In other examples, the materials of the first film layer and the third film layer can be different, for example, in the example of FIG. 8, the first film layer can be an aluminum oxide AlO layer, and the third film layer can be a hafnium oxide HfO layer.

[0086] In the examples of the application involving two film layers with the same material, it can be understood that the main materials of the two film layers, which can be the materials with the largest mass fraction, are the same. In the examples of the application involving two film layers with different materials, it can be understood that the main materials of the two film layers, which can be the materials with the largest mass fraction, are different.

[0087] In the examples of FIG. 7 and FIG. 8, the second film layer stacked between the first film layer and the third film layer can act as a separation interface, for example, the second film layer can be selected from at least one of silicon oxide SiO2 or tantalum oxide TaO.

[0088] In the examples of FIG. 7 and FIG. 8, the first film layer and the third film layer both have electronegativity, and the second film layer is selected from at least one of silicon oxide SiO2 or tantalum oxide TaO, as a separation layer of the first film layer and the third film layer.

[0089] FIG. 9 is another structure given by an embodiment of the application, in which the first film layer, the second film layer, and the third film layer all have electronegativity, the material of the second film layer is different from the material of the first film layer, and the material of the second film layer is different from the material of the third film layer.

[0090] In the example, not only the first film layer and the third film layer can induce holes in the semiconductor substrate, but also the second film layer stacked between the first film layer and the third film layer can induce holes. In this way, more holes can be generated on the surface of the semiconductor substrate, and the surface dark current of the semiconductor substrate can be better inhibited.

[0091] In the example, the materials of the first film layer and the third film layer can be the same, and the material of the second film layer is selected to be different and have electronegativity. For example, the first film layer and the third film layer are both aluminum oxide AlO layers, and the second film layer is a hafnium oxide HfO layer.

[0092] In another example, the materials of the first film layer, the second film layer, and the third film layer are all different. For example, the first film layer is an aluminum oxide AlO layer, the second film layer is a hafnium oxide HfO layer, and the third film layer is an aluminum nitride AlN layer.

[0093] In some optional structures, more layers with electronegativity can be stacked on the third film layer. As shown in FIGS. 11 and 12.

[0094] In FIGS. 11 and 12, an example is shown in which four film layers are stacked on the semiconductor substrate, and the first film layer, the second film layer, the third film layer, and the fourth film layer are stacked in turn away from the semiconductor substrate.

[0095] The fourth film layer can be selected to be at least one of a silicon oxide SiO2 layer or a tantalum oxide TaO layer, or a material with electronegativity.

[0096] In some examples, the material of the fourth film layer can be the same as the material of the second film layer. For example, in the example shown in FIG. 11, the second film layer and the fourth film layer are both silicon oxide SiO2 layers. In this example, the material of the first film layer and the material of the third film layer are the same, and both are aluminum oxide AlO layers. This structure is easy to implement in terms of process.

[0097] In the example shown in FIG. 12, the material of the fourth film layer is the same as the material of the second film layer, and the second film layer and the fourth film layer are both hafnium oxide HfO layers. In this example, the material of the first film layer and the material of the third film layer are the same, and both are aluminum oxide AlO layers.

[0098] In FIG. 13, an example is shown in which five film layers are stacked on the semiconductor substrate, and the first film layer, the second film layer, the third film layer, the fourth film layer, and the fifth film layer are stacked in turn away from the semiconductor substrate.

[0099] The material of the fifth film layer can be the same as the material of the first film layer, or the material of the fifth film layer can be the same as the material of the third film layer.

[0100] The first film layer, the third film layer and the fifth film layer can be made of materials with electronegativity, the second film layer is a boundary layer between the first film layer and the third film layer, and the fourth film layer is a boundary layer between the third film layer and the fifth film layer.

[0101] For example, in the example of FIG. 13, the first film layer, the third film layer and the fifth film layer are all AlO layers, and the second film layer and the fourth film layer are both SiO2 layers.

[0102] For another example, as shown in FIG. 14, the first film layer, the third film layer and the fifth film layer are all AlO layers, the second film layer is a HfO layer, and the fourth film layer is a SiO2 layer.

[0103] For another example, the first film layer and the third film layer are made of the same electronegative material, and the fifth film layer is made of a different electronegative material.

[0104] The structure of the stack of more layers such as the examples of FIGS. 11-14 can generate more holes on the surface of the semiconductor substrate, better suppress the dark current on the surface of the semiconductor substrate, and suppress the white spot phenomenon of the formed image.

[0105] The embodiment of the present application also provides a preparation method of an image sensor, and the image sensor prepared by using the method can suppress the dark current on the surface of the semiconductor substrate, weaken the white spot phenomenon, and improve the image quality.

[0106] As shown in FIG. 15, a process flow of a preparation method of an image sensor is given, which includes the following steps.

[0107] S1: forming a photoelectric conversion structure in a semiconductor substrate. For example, a photodiode is formed in the semiconductor substrate.

[0108] S2: sequentially preparing a first film layer, a second film layer and a third film layer on the light-incident side of the semiconductor substrate; the first film layer and the third film layer have electronegativity, the second film layer includes silicon oxide or tantalum oxide, or has electronegativity, the material of the second film layer is different from the material of the first film layer, and the material of the second film layer is different from the material of the third film layer.

[0109] In the preparation method of the example of the present application, at least three film layers can be prepared on the light-incident side of the semiconductor substrate, and these film layers include at least two film layers with electronegativity. More holes can be generated by using these film layers with electronegativity, so that the photoelectrons can avoid the defects introduced by the dangling bonds on the surface of the semiconductor substrate, and the dark current is reduced.

[0110] FIGS. 16A-16F exemplarily show structure schematic diagrams corresponding to respective steps in a preparation method of an image sensor.

[0111] As shown in FIG. 16A, a photoelectric conversion structure is prepared in a semiconductor substrate, for example, a photodiode is prepared.

[0112] Referring to FIG. 16B, a wiring layer is formed on the semiconductor substrate containing the photoelectric conversion structure, which is used to connect the photodiode or connect the photodiode and other electronic devices to form a circuit structure.

[0113] Referring to FIG. 16C, the structure formed in FIG. 16B is disposed on a chip, and the wiring layer faces the chip.

[0114] In some examples, the chip can be a logic chip used to control the image sensor. In other examples, the chip can be a carrier chip, which can be a wafer without devices.

[0115] Referring to FIG. 16D, the semiconductor substrate is thinned.

[0116] Referring to FIG. 16E, a film layer structure for suppressing dark current is formed on the side of the thinned semiconductor substrate away from the wiring layer.

[0117] For example, in FIG. 16E, a first film layer, a second film layer, and a third film layer are sequentially formed. The first film layer and the third film layer are both electronegative, and the second film layer serves as an interface layer between the first film layer and the third film layer. For example, the first film layer and the third film layer are both aluminum oxide AlO layers, and the second film layer is a silicon oxide SiO2 layer.

[0118] In some optional implementation processes, the first film layer, the second film layer, and the third film layer can be formed by using an atomic layer deposition (ALD) method. Alternatively, a chemical vapor deposition (CVD) or a physical vapor deposition (PVD) can also be used.

[0119] In some examples, the first film layer and the third film layer are formed by using the same material, such as both being aluminum oxide AlO, so as to be compatible with the existing CMOS process equipment and not to challenge the manufacturing process.

[0120] In another preparation process, more film layers with electronegativity can be formed on the third film layer.

[0121] Referring to FIG. 16F, a filter is disposed on the multilayer film layer structure formed in FIG. 16E. For example, the filter can be disposed by using a bonding process.

[0122] A microlens is disposed on the filter.

[0123] In the image sensor made by using the images shown in Figs. 16A to 16F, because the multilayer film layer structure with electronegativity is arranged on the side of the semiconductor substrate for receiving light, holes can be generated by using the film layer structure, and the holes can make photoelectrons avoid the defects introduced by dangling bonds on the surface of the semiconductor substrate, so that the dark current on the surface of the semiconductor substrate can be inhibited, and the white spot phenomenon of the image can be inhibited, and the imaging quality can be optimized.

[0124] In addition, when manufacturing the image sensor, the CMOS process can be compatible, and the manufacturing equipment and manufacturing process flow are not challenged.

[0125] The image sensor provided by the embodiments of the present application can have various integrated modes, and two exemplary modes are given as follows.

[0126] In one example, as shown in Fig. 17, a logic chip for controlling the image sensor can be three-dimensionally stacked with the image sensor.

[0127] In another example, as shown in Figs. 18 and 19, the pixel area and the logic area for controlling the pixel area of the image sensor can be integrated in one chip, for example, the logic area is arranged along the periphery of the pixel area, and the pixel logic integrated chip shown in Fig. 18, in which the pixel area and the logic area are integrated, is arranged on the carrier die.

[0128] In the description of the present specification, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0129] The above description is only a specific implementation of the present application, but the protection scope of the present application is not limited to this, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An image sensor, characterized by, The image sensor comprises: a semiconductor substrate having an incident light side for receiving light; a photoelectric conversion structure formed in the semiconductor substrate; a plurality of film layers including a first film layer, a second film layer, and a third film layer, which are stacked in sequence in a direction away from the semiconductor substrate on the incident light side; the first film layer and the third film layer have electronegativity; the second film layer comprises silicon oxide or tantalum oxide, or has electronegativity; the material of the second film layer is different from the material of the first film layer, and the material of the second film layer is different from the material of the third film layer.

2. The image sensor of claim 1, wherein, The material of the first film layer is the same as the material of the third film layer.

3. The image sensor of claim 1, wherein, The material of the first film layer is different from the material of the third film layer.

4. The image sensor according to claim 2 or 3, characterized in that, The material of the first film layer or the material of the third film layer comprises at least one of aluminum oxide, hafnium oxide, aluminum nitride, and aluminum oxynitride.

5. The image sensor according to any one of claims 1 to 4, wherein, The material of the second film layer with electronegativity comprises hafnium oxide.

6. The image sensor according to any one of claims 1 to 5, wherein, The plurality of film layers further comprises: a fourth film layer disposed on a side of the third film layer away from the second film layer; the material of the fourth film layer is the same as the material of the second film layer.

7. The image sensor of claim 6, wherein, The plurality of film layers further comprises: a fifth film layer disposed on a side of the fourth film layer away from the third film layer; the material of the fifth film layer is the same as the material of the first film layer, or the material of the fifth film layer is the same as the material of the third film layer.

8. The image sensor according to any one of claims 1 to 7, wherein, The image sensor further comprises a filter and a microlens; the filter is disposed on a side of the plurality of film layers away from the semiconductor substrate; the microlens is disposed on a side of the filter away from the plurality of film layers.

9. An electronic device, comprising: The image sensor comprises: a circuit board; the image sensor according to any one of claims 1-8 is electrically connected to the circuit board.

10. A method of fabricating an image sensor, characterized by, The preparation method comprises: forming a photoelectric conversion structure in a semiconductor substrate; sequentially preparing a first film layer, a second film layer, and a third film layer on an incident light side of the semiconductor substrate; the first film layer and the third film layer have electronegativity, the second film layer comprises silicon oxide or tantalum oxide, or has electronegativity, the material of the second film layer is different from the material of the first film layer, and the material of the second film layer is different from the material of the third film layer.

11. The method of claim 10, wherein, The material of the first film layer is the same as the material of the third film layer.

12. The method of claim 10, wherein, The material of the first film layer is different from the material of the third film layer.

13. The method according to claim 11 or 12, characterized in that, The material of the first film layer or the material of the third film layer comprises at least one of aluminum oxide, hafnium oxide, aluminum nitride, and aluminum oxynitride.

14. The method according to any one of claims 10-13, characterized in that, After the third film layer is prepared, the preparation method further comprises: preparing a fourth film layer on the third film layer, the material of the fourth film layer is the same as the material of the second film layer.

Images