WO2022141312A1 - Photosensitive sensor and manufacturing method therefor, and movable platform - Google Patents

Abstract

A photosensitive sensor, comprising one or more avalanche diodes, wherein each avalanche diode comprises: an active photosensitive region having a first side and a second side opposite to the first side, wherein the second side is provided with a light entrance surface; a first doped region and a second doped region located on the first side; and a first light reflecting structure close to the first side and provided opposite to the first doped region and the second doped region, and configured to reflect light from the active photosensitive region back to the active photosensitive region. The photosensitive sensor of the present application has high quantum absorption efficiency. Also provided are a manufacturing method and a movable platform.

Description

Photosensitive sensor, method for making the same, and movable platform technical field

The present application relates to the technical field of photosensitive sensors, and in particular, to a photosensitive sensor, a manufacturing method thereof, and a movable platform.

Background technique

Sensors using avalanche diodes (APD), such as time-of-flight sensors (TOF), are widely used in consumer electronics, security monitoring, industrial automation, artificial intelligence, Internet of Things and other fields for the collection and sorting of spatial distance data information for subsequent processing. and applications provide a source of information.

Silicon-based APDs are widely used, but due to the properties of silicon itself, its ability to absorb infrared light with longer wavelengths is weak, and a thicker active absorption region is required to have better quantum absorption efficiency (QE). It is difficult to form a thick active absorption region in the usual semiconductor process. Due to the insufficient thickness of the active absorption region, the quantum absorption efficiency is low, generally it is difficult to exceed 15%, and the sensor performance is low, which limits its application.

SUMMARY OF THE INVENTION

The present application provides a photosensitive sensor, a manufacturing method thereof, and a movable platform, which have high quantum absorption efficiency.

In a first aspect, an embodiment of the present application provides a photosensitive sensor, including: one or more avalanche diodes, each of the avalanche diodes includes:

The active photosensitive area has a first side and a second side opposite to the first side, and the second side is provided with a light incident surface:

a first doped region and a second doped region on the first side;

a first light-reflecting structure, located close to the first side and opposite to the first doped region and the second doped region, for reflecting light from the active photosensitive region back to the active photosensitive area.

In a second aspect, an embodiment of the present application provides a method for fabricating a photosensitive sensor, the method comprising:

provide a base;

One or more avalanche diodes are formed on the substrate, the avalanche diodes include an active photosensitive region, the active photosensitive region has a first side and a second side opposite the first side, and the The second side is provided with a light incident surface, and the avalanche diode further includes a first doped region and a second doped region located on the first side;

A first reflective structure is formed near the first side, the first reflective structure is disposed opposite the first doped region and the second doped region, and is used for reflecting light from the active photosensitive region back to the active photosensitive area.

In a third aspect, an embodiment of the present application provides a movable platform, including:

The aforementioned photosensitive sensor;

movement components;

a processor, wherein the processor controls the movement of the moving component according to the output signal of the photosensitive sensor.

The embodiments of the present application provide a photosensitive sensor, a method for manufacturing the same, and a movable platform. By arranging a reflective structure in the photosensitive sensor, at least part of the light can be repeatedly passed through the active photosensitive area, increasing the number of light in the active photosensitive area. Therefore, the probability of photons being absorbed can be increased, so that the photosensitive sensor has higher quantum absorption efficiency, and the detection accuracy and detection distance of the photosensitive sensor can be improved.

It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the disclosure of the embodiments of the present application.

Description of drawings

In order to explain the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a photosensitive sensor provided by an embodiment of the present application;

FIG. 2 is a schematic diagram of the principle of a photosensitive sensor used for distance measurement in an embodiment;

FIG. 3 is a schematic block diagram of a photosensitive sensor in one embodiment;

4 is a schematic structural diagram of a photosensitive sensor in an embodiment;

5 is a schematic structural diagram of a photosensitive sensor in another embodiment;

6 is a schematic structural diagram of a photosensitive sensor in another embodiment;

7 is a schematic structural diagram of a photosensitive sensor in yet another embodiment;

8 is a schematic structural diagram of a photosensitive sensor in yet another embodiment;

9a to 9d are schematic diagrams of non-planar structures;

10 is a schematic structural diagram of a photosensitive sensor in yet another embodiment;

11 is a schematic flowchart of a manufacturing method of a photosensitive sensor provided by an embodiment of the present application;

FIG. 12 is a schematic structural diagram of a movable platform provided by an embodiment of the present application.

Description of reference numerals: 100, avalanche diode; 110, active photosensitive region; 111, first side; 112, second side; 113, fourth doping region; 120, first doping region; 130, second doping region Impurity region; 140, first reflective structure; 150, third doped region; 160, fifth doped region; 170, second reflective structure; 171, deep trench; 172, passivation layer; 173, buffer layer; 101, light incident surface; 102, avalanche breakdown area; 10, readout circuit; 11, shallow trench isolation; 20, peripheral circuit; 30, non-planar structure; 31, blind hole; 32, trench; 700, movable platform; 710, photosensitive sensor; 720, motion component; 701, processor; 702, memory; 703, bus.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

The flowcharts shown in the figures are for illustration only, and do not necessarily include all contents and operations/steps, nor do they have to be performed in the order described. For example, some operations/steps can also be decomposed, combined or partially combined, so the actual execution order may be changed according to the actual situation.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and features in the embodiments may be combined with each other without conflict.

Please refer to FIG. 1. FIG. 1 is a schematic structural diagram of a photosensitive sensor provided by an embodiment of the present application. The photosensitive sensor includes an avalanche diode, a time-of-flight sensor, and/or a lidar.

In some embodiments, a photosensitive sensor may be used with the movable platform. Exemplarily, the movable platform may include at least one of an unmanned aerial vehicle, a gimbal, an unmanned vehicle, an assisted driving vehicle, an unmanned vehicle, and the like. Further, the unmanned aerial vehicle may be a rotary-wing drone, such as a quad-rotor drone, a hexa-rotor drone, an octa-rotor drone, or a fixed-wing drone.

Exemplarily, the photosensitive sensor is used for three-dimensional scanning and spatial distance measurement, such as lidar/autopilot/drone barrier/AR (Augmented Reality, augmented reality)/VR (Virtual Reality, virtual reality)/artificial intelligence, etc. Provide input information.

Exemplarily, as shown in Figure 2, the light source is used to actively emit light to illuminate the object, and then the photosensitive sensor is used to receive the light reflected from the object. According to the distance between different positions on the object and the photosensitive sensor, three-dimensional (3D) information of the object can also be obtained.

Exemplarily, the infrared light of a specific wavelength is emitted to illuminate the object, and the avalanche diode 100 is used to receive the infrared light of the specific wavelength reflected back by the object, so as to avoid the interference of natural light in the environment.

Specifically, as shown in FIG. 1 and FIG. 3 , the photosensitive sensor includes one or more avalanche diodes 100 . Exemplarily, the adjacent avalanche diodes 100 may be isolated by a deep trench isolation (DTI for short) structure or a shallow trench isolation (STI for short) structure to prevent crosstalk between the avalanche diodes 100 . .

For example, the avalanche diode 100 includes an avalanche photodiode (Avalanche Photon Diode, APD). Avalanche photodiodes usually add reverse bias to the P-N junction of a photodiode made of silicon or germanium, and the incident light is absorbed by the P-N junction to form a photocurrent. Increasing the reverse bias will generate a photocurrent. The phenomenon of "avalanche" (that is, the photocurrent surges exponentially), so this kind of diode is called an avalanche photodiode.

In some embodiments, as shown in FIG. 3 , the photosensor further includes a readout circuit 10 . The readout circuit 10 includes, for example, an amplifier, such as a transimpedance amplifier, capable of converting the photocurrent into a voltage signal. Of course, it is not limited to this, for example, the readout circuit 10 may also include a temperature compensation circuit or the like.

In some embodiments, as shown in FIG. 3 , the photosensitive sensor further includes a peripheral circuit 20, and the peripheral circuit 20 is used to provide a reverse bias voltage to the avalanche diode 100, of course, it is not limited to this, for example, the peripheral circuit 20 can be used to Calculate the distance from the measured object from the time from emission to reflection.

Specifically, as shown in FIG. 1 , each avalanche diode 100 includes: an active photosensitive region 110 , a first doped region 120 and a second doped region 130 , and a first reflective structure 140 .

Wherein, as shown in FIG. 1 , the active photosensitive region 110 has a first side 111 and a second side 112 opposite to the first side 111 , and the second side 112 is provided with a light incident surface 101 . The first doped region 120 and the second doped region 130 are located on the first side 111 . Exemplarily, the light incident surface 101 may be the surface itself of the second side 112 of the active photosensitive area 110 , but is not limited thereto, for example, may also be the surface of the photosensitive sensor substrate on the side away from the active photosensitive area 110 . The substrate may include a substrate and/or an epitaxial layer.

In some embodiments, the doping type of the first doped region 120 and the doping type of the second doped region 130 are different. For example, the first doping region 120 is P-type doping, and the second doping region 130 is N-type doping; or the first doping region 120 is N-type doping, and the second doping region 130 is P-type doping .

Exemplarily, the first doped region 120 is used for electrically connecting a first applied voltage, and the second doped region 130 is used for electrically connecting a second applied voltage, and the first applied voltage is different from the second applied voltage. It can be understood that a reverse bias voltage can be provided to the avalanche diode 100 through the first doped region 120 and the second doped region 130 .

Exemplarily, metal lines are also provided near the first side 111 , for example, a metal line connected to the first doped region 120 and a metal line connected to the second doped region 130 are provided. The side of the photosensitive sensor close to the first side 111 can be referred to as the front of the photosensitive sensor, and the side close to the second side 112 can be referred to as the back of the photosensitive sensor, and the second side 112 of the active photosensitive area 110 is provided with a light incident surface 101 , that is, the photosensitive sensor enters the light through the back, so the photosensitive sensor can be called a back-illuminated photosensitive sensor. When light enters the active photosensitive area 110 from the front of the photosensitive sensor, it can be prevented from being blocked by the metal wire, and the detection accuracy and detection distance of the photosensitive sensor can be improved by entering light from the back.

Specifically, as shown in FIG. 1 , the first light-reflecting structure 140 is located close to the first side 111 and opposite to the first doped region 120 and the second doped region 130 , and is used to reflect the light from the active photosensitive region 110 back to the active photosensitive region 110 . It can be understood that if the photosensitive sensor does not include the first reflective structure 140, the light from the active photosensitive area 110 will not enter the active photosensitive area 110 after penetrating the active photosensitive area 110. The first reflective structure 140 can enable at least part of the light to travel through the active photosensitive area 110 repeatedly, increasing the optical path in the active photosensitive area 110, thereby increasing the probability of photons being absorbed, so that the photosensitive sensor has a higher The quantum absorption efficiency can improve the detection accuracy and detection distance of the photosensitive sensor.

Exemplarily, when the photosensitive sensor includes a plurality of avalanche diodes 100 , the first light-reflecting structures 140 of different avalanche diodes 100 may be provided separately, or may be provided integrally. It can be determined according to the manufacturing process of the photosensitive sensor. When the first light-reflecting structures 140 of different avalanche diodes 100 are integrally disposed, the light penetrating the active photosensitive region 110 can be prevented from being transmitted through the space between the first light-reflecting structures 140 of adjacent avalanche diodes 100, so the quantum absorption efficiency higher.

In some embodiments, the surface of the first light-reflecting structure 140 facing the active photosensitive region 110 includes a plane and/or a non-planar curved surface. As shown in FIG. 1 , the surface of the first reflective structure 140 facing the active photosensitive region 110 includes a flat surface. As shown in FIG. 4 , the surface of the first reflective structure 140 facing the active photosensitive region 110 includes a curved surface. Of course, it is not limited to this. For example, the surface of the first light-reflecting structure 140 facing the active photosensitive area 110 may also include an irregular plane, and the light from the active photosensitive area 110 may also be reflected back to the active photosensitive area 110 .

Exemplarily, the curved surface includes at least one of an inner side surface of a cylinder, an inner side surface of an elliptical cylinder, an inner side surface of a sphere, and an inner side surface of an ellipsoid. As shown in FIG. 4 , the curved surface includes the inner side surface of an elliptical cylinder or the inner side surface of an ellipsoid.

In some embodiments, the first light-reflecting structure 140 converges and reflects the light from the active photosensitive area 110 back to the active photosensitive area 110 . For example, when the surface of the first light-reflecting structure 140 facing the active photosensitive region 110 includes a non-planar curved surface, the convergent reflection of light can be achieved, as shown in FIG. 4 , so that at least part of the light reflected back to the active photosensitive region 110 can be The active photosensitive region 110 has a larger optical path and has a higher quantum absorption efficiency.

In some embodiments, the first light-reflecting structure 140 diffusely reflects light from the active photosensitive area 110 back to the active photosensitive area 110 . Exemplarily, the surface of the first light-reflecting structure 140 facing the active photosensitive region 110 may be a rough surface, such as a rough plane or a rough non-planar curved surface, so that at least part of the light reflected back to the active photosensitive region 110 can be The photosensitive area 110 has a larger optical path. For example, when light vertically incident on the active photosensitive area 110 is reflected by the first light-reflecting structure 140 , it is reflected back to the active photosensitive area 110 at a larger angle and has a larger optical path. , with high quantum absorption efficiency.

In some embodiments, the first light-reflecting structure 140 includes a metal layer. For example, the material of the metal layer is aluminum, copper, gold, tungsten, or an alloy of at least one of them. Of course, it is not limited to this, for example, the first light-reflecting structure 140 includes an oxide layer, such as a silicon dioxide layer.

In some embodiments, the first light-reflecting structure 140 is spaced apart from or integrated with the first doped region 120 and the second doped region 130 . The details can be determined according to the manufacturing process of the photosensitive sensor.

In some embodiments, the projection of the first light-reflecting structure 140 on the active photosensitive region 110 at least covers the entire active photosensitive region 110 . Therefore, all the light passing through the first side 111 of the active photosensitive region 110 can be reflected back to the active photosensitive region 110 , with higher quantum absorption efficiency.

For example, referring to FIG. 5, a portion of the first doped region 120 and a third doped region 150 form the avalanche breakdown region 102, and the electric field between the first doped region 120 and the second doped region 130 can The carriers generated by driving the active photosensitive region 110 to induce incident light generate an avalanche effect in the avalanche breakdown region 102 , so that the first doped region 120 and the second doped region 130 are turned on. It can be understood that the specific structure of the avalanche diode 100 is not limited to this, and FIG. 5 is only for illustration.

In some embodiments, as shown in FIG. 5 , the active photosensitive region 110 includes a fourth doping region 113 , and the doping concentration of the fourth doping region 113 is lower than that of the first doping region 120 and/or the second doping region 113 . Concentration in region 130. Therefore, the active photosensitive region 110 is relatively easy to induce incident light to generate carriers.

Exemplarily, as shown in FIG. 5 , the third doping region 150 is located between the first doping region 120 and the active photosensitive region 110 , and the doping concentration of the third doping region 150 is lower than Doping concentration of the first doping region 120 and/or the second doping region 130 .

Exemplarily, the doping concentration of the third doping region 150 is higher than the doping concentration of the fourth doping region 113 , so that the carriers induced by the active light-sensing region 110 have an avalanche effect in the avalanche breakdown region 102 .

In some embodiments, as shown in FIG. 5 , the avalanche diode 100 further includes a fifth doped region 160 located between the first doped region 120 and the second doped region 130; the fifth doped region 160 is located between the first doped region 120 and the second doped region 130; The doping concentration of the impurity region 160 is lower than the doping concentration of the first doping region 120 and/or the second doping region 130 . The first doped region 120 and the second doped region 130 are turned on only when the avalanche effect occurs in the avalanche breakdown region 102, thereby improving the accuracy of the photosensitive sensor.

Exemplarily, as shown in FIG. 5 , the first doped region 120 and the third doped region 150 are arranged in layers, and the layers of the stacked first doped region 120 and the third doped region 150 are located in the fifth doped region 160 . On one side, the second doped region 130 is located on the other side of the fifth doped region 160 .

Exemplarily, the doping types of the first doping region 120 and the fifth doping region 160 are different from the doping types of the second doping region 130 , the third doping region 150 and the fourth doping region 113 ; The doping concentration of the first doping region 120 is higher than that of the fifth doping region 160 , the doping concentration of the second doping region 130 is higher than that of the third doping region 150 , and the doping concentration of the third doping region 150 is higher than that of the third doping region 150 . The doping concentration of 150 is higher than that of the fourth doping region 113 .

For example, the doping type of the first doping region 120 and the fifth doping region 160 is P-type doping, and the doping type of the second doping region 130 , the third doping region 150 , and the fourth doping region 113 are P-type doping. Type is N-type doped. Or the doping type of the first doping region 120 and the fifth doping region 160 is N-type doping, and the doping type of the second doping region 130 , the third doping region 150 and the fourth doping region 113 is P type doping.

Exemplarily, the first doped region 120 is a P+ type heavily doped region, the second doped region 130 is an N+ heavily doped region, the third doped region 150 is an N type doped region, and the fourth doped region 113 is an N-lightly doped region. The first doping region 120 can be connected to a negative voltage (-10V to -30V), the second doping region 130 can be connected to a positive voltage (0v to 10V), and the fourth doping region 113 is an active region for photon absorption, where light is The region is absorbed to generate electron/hole pairs, and the photogenerated electron-hole pairs enter the third doped region 150 after being accelerated by an electric field, and an avalanche effect occurs when driven by a strong electric field.

Optionally, referring to FIG. 6 , the photosensitive sensor further includes a second reflective structure 170 perpendicular to the surface of the second side 112 , and the second reflective structure 170 is disposed on at least one side of the active photosensitive area 110 ; the second reflective structure 170 It is used to reflect the light from the active photosensitive area 110 back to the active photosensitive area 110 .

As shown in FIG. 6 , by arranging the second light-reflecting structure 170 in the photosensitive sensor, at least part of the light can pass through the active photosensitive area 110 repeatedly, and the optical path in the active photosensitive area 110 is increased, thereby increasing the The probability of photons being absorbed makes the photosensitive sensor have high quantum absorption efficiency, which can improve the detection accuracy and detection distance of the photosensitive sensor.

In some embodiments, as shown in FIG. 6 , the second light-reflecting structure 170 is formed in the deep trench 171 on at least one side of the active photosensitive region 110 . Therefore, the second light-reflecting structure 170 can be provided in the photosensitive sensor through the semiconductor processing technology. For example, after the front surface device of the photosensitive sensor is completed, the deep trench 171 and the second reflective structure 170 are formed by etching the back surface of the photosensitive sensor to the front surface.

Exemplarily, as shown in FIG. 6 , the deep trench 171 extends from the second side 112 toward the first side 111 , so the deep trench 171 may be referred to as a deep back trench 171 (BDTI).

Exemplarily, the second light-reflecting structure 170 includes HK dielectric material filled in the deep trench 171 . For example, the HK dielectric material includes at least one of hafnium oxide, aluminum oxide, and tantalum oxide. Exemplarily, as shown in FIG. 7 , the HK dielectric material induces a passivation layer 172 on the side of the active photosensitive region 110 close to the second light-reflecting structure 170 , and the passivation layer 172 generates less carriers than the active photosensitive region 170 . Carriers generated by the rest of the region 110 except for the passivation layer 172 . The HK dielectric material filled in the deep trench 171 can induce a hole accumulation layer on the surface of silicon close to silicon dioxide, which can passivate the silicon surface and reduce the interference of surface carrier emission on the device. .

Exemplarily, the second light-reflecting structure 170 further includes a buffer layer 173 between the HK dielectric material and the trench walls of the deep trench 171 . For example, the buffer layer 173 includes a silicon dioxide buffer layer 173 . The silicon dioxide buffer layer 173 is disposed close to the silicon interface of the deep trench 171 .

Optionally, referring to FIG. 8 , the light incident surface 101 is provided with a non-planar structure 30 , and the non-planar structure 30 can change the direction in which light enters the active photosensitive region 110 . By providing the non-planar structure 30 on the light incident surface 101, at least part of the light can be incident on the active photosensitive region 110 at a larger angle, thereby increasing the optical path in the active photosensitive region 110, thereby increasing the amount of light absorbed by the photons. probability, so that the photosensitive sensor has high quantum absorption efficiency, which can improve the detection accuracy and detection distance of the photosensitive sensor. For example, when the light enters the light incident surface 101 perpendicularly, the non-planar structure 30 increases the angle of the light entering the active photosensitive region 110, and can be incident on the active photosensitive region 110 obliquely. Since the active photosensitive region 110 is relatively thin, the light is inclined Incident to the active photosensitive region 110 can increase the optical path of light in the active photosensitive region 110 . When light is obliquely incident on the active photosensitive region 110 , the first light-reflecting structure 140 can also reflect the light to be obliquely incident back to the active photosensitive region 110 , so that the photosensitive sensor has higher quantum absorption efficiency.

In some embodiments, the non-planar structure 30 includes blind holes 31 and/or trenches 32 , which can be formed by an etching process, as shown in FIGS. 9 a to 9 d , where the shaded parts are parts that need to be etched.

For example, the blind holes 31 may include blind holes 31 with a circular cross section and/or blind holes 31 with a square cross section, but certainly not limited thereto, for example, may include blind holes 31 with a rectangular cross section and the like. For example, the grooves 32 include at least one of linear grooves, spiral grooves, and annular grooves.

Exemplarily, as shown in FIGS. 8 and 9 , the hole wall of the blind hole 31 and/or the groove wall of the groove 32 is perpendicular to the surface of the second side 112 or forms an obtuse angle or an acute angle.

Exemplarily, as shown in FIGS. 8 and 9 , the width of the notch of the groove 32 is greater than or equal to the width of the groove bottom of the groove 32 .

Exemplarily, as shown in FIGS. 9 a to 9 d , a plurality of grooves 32 are arranged in parallel or at least two grooves 32 are intersected.

In some embodiments, as shown in FIG. 10 , the photosensitive sensor includes a first reflective structure 140 , a second reflective structure 170 and a non-planar structure 30 of the light incident surface 101 . More light can be made to repeatedly pass through the active photosensitive area 110, and the optical path in the active photosensitive area 110 can be increased, thereby increasing the probability of photons being absorbed, so that the photosensitive sensor has higher quantum absorption efficiency, The detection accuracy and detection distance of the photosensitive sensor can be improved.

In some embodiments, as shown in FIG. 10 , a shallow trench isolation 11 is provided between the readout circuit 10 and the first doped region 120 , the second doped region 130 , and the avalanche breakdown region 102 to increase the photosensitive Changan device’s reliability.

In the photosensitive sensor provided by the embodiments of the present application, by arranging a reflective structure in the photosensitive sensor, at least part of the light can be repeatedly passed through the active photosensitive area, and the optical path in the active photosensitive area can be increased, thereby increasing the photons being absorbed by the photons. The probability of absorption makes the photosensitive sensor have high quantum absorption efficiency, which can improve the detection accuracy and detection distance of the photosensitive sensor.

Please refer to FIG. 11 in conjunction with the foregoing embodiment. FIG. 11 is a schematic flowchart of a manufacturing method of a photosensitive sensor provided by another embodiment of the present application.

As shown in FIG. 11 , the manufacturing method of the embodiment of the present application includes steps S110 to S130.

S110, providing a substrate.

The substrate may include a substrate and/or an epitaxial layer.

S120, forming one or more avalanche diodes on the substrate, the avalanche diodes including an active photosensitive region, the active photosensitive region having a first side and a second side opposite to the first side, The second side is provided with a light incident surface, and the avalanche diode further includes a first doped region and a second doped region located on the first side.

Exemplarily, thinning processing is performed on the backside of the photosensitive sensor, that is, the substrate, the entire substrate can be removed, or a part of the substrate can be removed, for example, a part of the substrate is still left on the second side of the active photosensitive region. Exemplarily, the light incident surface may be the surface itself of the second side of the active photosensitive region, but is not limited thereto, for example, it may also be the surface of the photosensitive sensor substrate on the side away from the active photosensitive region.

S130 , forming a first light-reflecting structure near the first side, the first light-reflecting structure is disposed opposite the first doping region and the second doping region, and is used to convert the light from the active photosensitive region Light is reflected back to the active photosensitive area.

Exemplarily, the surface of the first light-reflecting structure facing the active photosensitive region includes a plane and/or a non-planar curved surface.

Exemplarily, the first light-reflecting structure includes a metal layer.

Exemplarily, the first light-reflecting structure and the first doped region and the second doped region are arranged spaced apart or integrally arranged.

Exemplarily, the projection of the first light-reflecting structure on the substrate at least covers all the active photosensitive regions.

In some embodiments, the manufacturing method further includes: forming a second light-reflecting structure perpendicular to the substrate on a side of the substrate away from the avalanche diode, and the second light-reflecting structure is disposed on the active photosensitive the outer side of the area; the second light-reflecting structure is used for reflecting the light from the active photosensitive area back to the active photosensitive area.

Exemplarily, forming a second light-reflecting structure perpendicular to the substrate on the side of the substrate away from the avalanche diode includes: forming a deep trench on the side of the substrate away from the avalanche diode; The deep trenches are filled with HK dielectric material.

Exemplarily, before filling the deep trench with the HK dielectric material, a buffer layer is formed on the groove wall of the deep trench.

In some embodiments, the manufacturing method further includes: forming a non-planar structure on the light incident surface, and the non-planar structure can change the direction in which light enters the active photosensitive region.

Exemplarily, the non-planar structures include blind holes and/or trenches.

The specific principles and implementation manners of the manufacturing method of the photosensitive sensor provided by the embodiment of the present application are similar to those of the photosensitive sensor of the foregoing embodiments, and are not repeated here.

In the manufacturing method of the photosensitive sensor provided by the embodiment of the present application, by arranging a reflective structure in the photosensitive sensor, at least part of the light can be repeatedly passed through the active photosensitive area, and the optical path in the active photosensitive area is increased, so that it can be Increasing the probability of photons being absorbed makes the photosensitive sensor have higher quantum absorption efficiency, which can improve the detection accuracy and detection distance of the photosensitive sensor.

Please refer to FIG. 12 in conjunction with the foregoing embodiments. FIG. 12 is a schematic block diagram of a movable platform 700 provided by an embodiment of the present application. Exemplarily, the movable platform may include at least one of an unmanned aerial vehicle, a gimbal, an unmanned vehicle, and the like. Further, the unmanned aerial vehicle may be a rotary-wing drone, such as a quad-rotor drone, a hexa-rotor drone, an octa-rotor drone, or a fixed-wing drone.

As shown in FIG. 12 , the movable platform includes the photosensitive sensor 710 and the motion component 720 of the previous embodiment. The motion assembly 720 may include one or more propellers, one or more motors corresponding to the one or more propellers, and one or more electronic governors (referred to as ESCs for short).

Photosensitive sensors 710 include, for example, avalanche diodes, time-of-flight sensors, and/or lidars. Exemplarily, the photosensitive sensor is used for three-dimensional scanning and spatial distance measurement, such as lidar/autopilot/drone barrier/AR (Augmented Reality, augmented reality)/VR (Virtual Reality, virtual reality)/artificial intelligence, etc. Provide input information.

The movable platform 700 includes one or more processors 701 , and the one or more processors 701 work individually or collectively to control the movement of the motion component 720 according to the output signal of the photosensitive sensor 710 .

Illustratively, the removable platform 700 further includes a memory 702 for storing program instructions.

Exemplarily, the processor 701 and the memory 702 are connected through a bus 703, and the bus 703 is, for example, an I2C (Inter-integrated Circuit) bus.

Specifically, the processor 701 may be a micro-controller unit (Micro-controller Unit, MCU), a central processing unit (Central Processing Unit, CPU) or a digital signal processor (Digital Signal Processor, DSP) or the like.

Specifically, the memory 702 may be a Flash chip, a read-only memory (ROM, Read-Only Memory) magnetic disk, an optical disk, a U disk, a mobile hard disk, and the like.

The one or more processors 701 are configured to call program instructions stored in the memory 702 , and when executing the program instructions, control the motion component 720 to move according to the output signal of the photosensitive sensor 710 .

The specific principles and implementation manners of the movable platform provided by the embodiments of the present application are similar to the photosensitive sensors of the foregoing embodiments, and details are not described herein again.

It should be understood that the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the application.

It will also be understood that, as used in this application and the appended claims, the term "and/or" refers to and including any and all possible combinations of one or more of the associated listed items.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalents within the technical scope disclosed in the present application. Modifications or substitutions shall be covered by the protection scope of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (47)

A photosensitive sensor, comprising: one or more avalanche diodes, each of the avalanche diodes comprising: The active photosensitive area has a first side and a second side opposite to the first side, and the second side is provided with a light incident surface: a first doped region and a second doped region on the first side; a first light-reflecting structure, located close to the first side and opposite to the first doped region and the second doped region, for reflecting light from the active photosensitive region back to the active photosensitive area. The photosensitive sensor according to claim 1, wherein a surface of the first light-reflecting structure facing the active photosensitive region comprises a plane and/or a non-planar curved surface. The photosensitive sensor according to claim 2, wherein the curved surface comprises at least one of an inner side surface of a cylinder, an inner side surface of an elliptical cylinder, an inner side surface of a sphere, and an inner side surface of an ellipsoid. The photosensitive sensor according to any one of claims 1-3, wherein the first reflective structure condenses and reflects the light from the active photosensitive area back to the active photosensitive area. The photosensitive sensor according to any one of claims 1-3, wherein the first reflective structure diffusely reflects light from the active photosensitive area back to the active photosensitive area. The photosensitive sensor according to any one of claims 1-3, wherein the first reflective structure comprises a metal layer. The photosensitive sensor according to claim 6, wherein the material of the metal layer is aluminum, copper, gold, tungsten, or an alloy of at least one of them. The photosensitive sensor according to any one of claims 1-3, wherein the first light-reflecting structure and the first doped region and the second doped region are arranged spaced apart or integrally arranged. The photosensitive sensor according to any one of claims 1-3, wherein the projection of the first light-reflecting structure on the active photosensitive area at least covers all of the active photosensitive area. The photosensitive sensor according to any one of claims 1-9, further comprising a second light-reflecting structure perpendicular to the surface of the second side, the second light-reflecting structure being disposed on the active photosensitive at least one side of the area; the second light-reflecting structure is used for reflecting the light from the active photosensitive area back to the active photosensitive area. The photosensitive sensor according to claim 10, wherein the second light-reflecting structure is formed in a deep trench on at least one side of the active photosensitive region. The photosensitive sensor according to claim 11, wherein the second light-reflecting structure comprises HK dielectric material filled in the deep trench. The photosensitive sensor according to claim 12, wherein the HK dielectric material comprises at least one of hafnium oxide, aluminum oxide, and tantalum oxide. The photosensitive sensor according to claim 12, wherein the HK dielectric material induces a passivation layer on the side of the active photosensitive region close to the second light-reflecting structure, and the passivation layer produces a passivation layer. The carriers are less than those generated by the rest of the active photosensitive region except the passivation layer. The photosensitive sensor according to claim 12, wherein the second light-reflecting structure further comprises a buffer layer located between the HK dielectric material and the groove wall of the deep trench. The photosensor according to claim 15, wherein the buffer layer comprises a silicon dioxide buffer layer. 12. The photosensor of claim 11, wherein the deep trench extends toward the first side on the second side. The photosensitive sensor according to any one of claims 1-17, wherein the light incident surface is provided with a non-planar structure, and the non-planar structure can change the direction in which light enters the active photosensitive region. The photosensitive sensor according to claim 18, wherein the non-planar structure comprises blind holes and/or trenches. The photosensitive sensor according to claim 19, wherein the hole wall of the blind hole and/or the groove wall of the groove are perpendicular to the surface of the second side or at an obtuse angle or at an acute angle. The photosensitive sensor according to claim 19, wherein the width of the notch of the groove is greater than or equal to the width of the groove bottom of the groove. The photosensitive sensor according to claim 19, wherein a plurality of the grooves are arranged in parallel or at least two of the grooves are arranged to intersect. The photosensitive sensor according to claim 19, wherein the groove comprises at least one of a linear groove, a spiral groove, and an annular groove. The photosensitive sensor according to any one of claims 1-23, wherein the doping type of the first doped region and the doping type of the second doped region are different. The photosensitive sensor according to claim 24, wherein the first doped region is electrically connected to a first applied voltage, the second doped region is electrically connected to a second applied voltage, and the first applied voltage is connected to the first applied voltage. The second applied voltage is different. The photosensitive sensor according to claim 25, wherein a portion of the first doped region and the third doped region form an avalanche breakdown region, and a portion between the first doped region and the second doped region forms an avalanche breakdown region. The electric field can drive the carriers generated by the active photosensitive region to induce an avalanche effect in the avalanche breakdown region, so that the first doped region and the second doped region are turned on. The photosensitive sensor according to claim 26, wherein the active photosensitive region comprises a fourth doping region, and the doping concentration of the fourth doping region is lower than that of the first doping region and/or concentration of the second doped region. The photosensitive sensor according to claim 27, wherein the third doping region is located between the first doping region and the active photosensitive region, and the third doping region is the third doping region. The doping concentration of the region is lower than the doping concentration of the first doping region and/or the second doping region. The photosensitive sensor according to claim 28, wherein the doping concentration of the third doping region is higher than the doping concentration of the fourth doping region. The photosensor according to claim 28, wherein the avalanche diode further comprises a fifth doping region, the fifth doping region is located between the first doping region and the second doping region time; the doping concentration of the fifth doping region is lower than the doping concentration of the first doping region and/or the second doping region. The photosensitive sensor according to claim 30, wherein the first doped region and the third doped region are arranged in layers, and the layers of the stacked first doped region and the third doped region are located in On one side of the fifth doping region, the second doping region is located on the other side of the fifth doping region. The photosensitive sensor according to claim 31, wherein the first doping region, the doping type of the fifth doping region and the second doping region, the third doping region, The doping types of the fourth doping region are different; the doping concentration of the first doping region is higher than the doping concentration of the fifth doping region, and the doping concentration of the second doping region The doping concentration of the third doping region is higher than the doping concentration of the third doping region, and the doping concentration of the fourth doping region is higher. The photosensitive sensor according to claim 32, wherein the doping type of the first doping region and the fifth doping region is P-type doping, and the second doping region and the fifth doping region are P-type doping. The doping type of the third doping region and the fourth doping region is N-type doping; or The doping type of the first doping region and the fifth doping region is N-type doping, and the doping type of the second doping region, the third doping region and the fourth doping region is N-type doping. The heterotype is P-type doping. The photosensitive sensor according to any one of claims 1-26, wherein the photosensitive sensor further comprises a readout circuit, the readout circuit is connected to the first doped region, the second doped region, Shallow trench isolation is provided between the avalanche breakdown regions. The photosensitive sensor according to any one of claims 1-34, wherein the photosensitive sensor comprises an avalanche diode, a time-of-flight sensor and/or a lidar. A manufacturing method of a photosensitive sensor, characterized in that the method comprises: provide a base; One or more avalanche diodes are formed on the substrate, the avalanche diodes include an active photosensitive region, the active photosensitive region has a first side and a second side opposite the first side, and the The second side is provided with a light incident surface, and the avalanche diode further includes a first doped region and a second doped region located on the first side; A first reflective structure is formed near the first side, the first reflective structure is disposed opposite the first doped region and the second doped region, and is used for reflecting light from the active photosensitive region back to the active photosensitive area. The manufacturing method according to claim 36, wherein the surface of the first light-reflecting structure facing the active photosensitive region comprises a plane and/or a non-planar curved surface. The manufacturing method according to claim 36, wherein the first light-reflecting structure comprises a metal layer. The manufacturing method according to claim 36, wherein the first light-reflecting structure and the first doped region and the second doped region are arranged spaced apart or integrally arranged. The manufacturing method according to claim 36, wherein the projection of the first light-reflecting structure on the substrate at least covers all the active photosensitive regions. The manufacturing method according to any one of claims 36-40, wherein the manufacturing method further comprises: A second reflective structure perpendicular to the substrate is formed on the side of the substrate away from the avalanche diode, and the second reflective structure is disposed outside the active photosensitive region; the second reflective structure is used to Light from the active photosensitive area is reflected back to the active photosensitive area. The manufacturing method according to claim 41, wherein the forming a second light-reflecting structure perpendicular to the substrate on the side of the substrate away from the avalanche diode comprises: forming a deep trench on a side of the substrate away from the avalanche diode; The deep trenches are filled with HK dielectric material. The manufacturing method according to claim 42, wherein a buffer layer is formed on the groove wall of the deep groove before the HK dielectric material is filled in the deep groove. The manufacturing method according to any one of claims 36-43, wherein the manufacturing method further comprises: A non-planar structure is formed on the light incident surface, and the non-planar structure can change the direction in which light enters the active photosensitive region. The manufacturing method according to claim 44, wherein the non-planar structure comprises blind holes and/or trenches. A movable platform is characterized in that, comprising: The photosensitive sensor of any one of claims 1-35; movement components; a processor, wherein the processor controls the movement of the moving component according to the output signal of the photosensitive sensor. The movable platform according to claim 46, wherein the movable platform comprises at least one of the following: an unmanned aerial vehicle, a gimbal, and an unmanned vehicle.

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