CN116435378A - Semiconductor device with a semiconductor layer having a plurality of semiconductor layers - Google Patents

Abstract

The application provides a semiconductor device, including a substrate, a light reflection layer and an epitaxial layer, the light reflection layer is arranged on the substrate; the epitaxial layer is arranged on the side of the light reflection layer away from the substrate, and the side of the epitaxial layer away from the substrate has The P-type doped part, the first P-type part and the floating diffusion part, the P-type doped part is arranged in contact with the first P-type part, the P-type doped part is in contact with the light reflection layer, and the first P-type part is in contact with the light reflection layer. The layers are arranged at intervals, and the floating diffusion part is located in the first P-type part and arranged at intervals with the P-type doped part, so as to improve the light conversion efficiency.

Description

Semiconductor device

technical field

The present application relates to the technical field of semiconductors, and in particular to a semiconductor device.

Background technique

For photodiode (photodiode) devices, the epitaxial layer is a crucial structure, which has many effects on photoelectric conversion efficiency and dark current. However, when the wavelength of the received light changes, the light conversion efficiency of the epitaxial layer is not good. For example, when the wavelength of light changes to the non-visible light region, for example, the received light is infrared light, the existing epitaxial layer design cannot meet the requirements of non-visible light. conversion requirements, resulting in poor photoconversion efficiency.

Contents of the invention

In view of this, the present application provides a semiconductor device to improve light conversion efficiency.

The application provides a semiconductor device, including:

Substrate;

a light reflective layer disposed on the substrate;

an epitaxial layer disposed on the side of the light reflection layer away from the substrate, the side of the epitaxial layer away from the substrate has a P-type doped part, a first P-type part and a floating diffusion part, the The P-type doped part is arranged in contact with the first P-type part, the P-type doped part is in contact with the light reflection layer, the first P-type part is arranged at intervals from the light reflection layer, and the floating The diffusion part is located in the first P-type part and spaced apart from the P-type doped part.

In some embodiments, the material of the light reflection layer includes at least one of silicon nitride, silicon oxynitride and silicon oxide.

In some embodiments, the thickness of the light reflection layer is 400-1000 nm.

In some embodiments, the side of the epitaxial layer is provided with an isolation part.

In some embodiments, the isolation part is an ion-doped part.

In some embodiments, the material of the isolation part is an insulating material.

In some embodiments, the thickness of the epitaxial layer is 3-4um.

In some embodiments, it further includes a first N-type portion and a second P-type portion, the first N-type portion is located between the P-type doped portion and the second P-type portion.

In some embodiments, it further includes a second N-type portion located in the first P-type portion, and the second N-type portion is located on a side of the floating diffusion portion away from the P-type doped portion, And it is spaced apart from the floating diffusion part.

In some embodiments, a polysilicon portion is provided on a side of the epitaxial layer away from the substrate, and the polysilicon portion is located on the first P-type portion.

The application provides a semiconductor device, including a substrate, a light reflection layer and an epitaxial layer, the light reflection layer is arranged on the substrate; the epitaxial layer is arranged on the side of the light reflection layer away from the substrate, and the side of the epitaxial layer away from the substrate has The P-type doped part, the first P-type part and the floating diffusion part, the P-type doped part is arranged in contact with the first P-type part, the P-type doped part is in contact with the light reflection layer, and the first P-type part is in contact with the light reflection layer. The layers are arranged at intervals, and the floating diffusion part is located in the first P-type part and arranged at intervals with the P-type doped part. A light reflective layer is set between the epitaxial layer and the substrate, so that when the light passes through the epitaxial layer, it is reflected at the interface between the epitaxial layer and the light reflective layer, thereby reflecting the light back into the epitaxial layer, thereby reducing the absorption length purpose, and reduce the light penetration rate, thereby improving the light conversion efficiency, at the same time, because most of the light is reflected by the light reflective layer, reducing the light irradiation into the substrate, thereby reducing the possibility of light crosstalk between substrates , thereby improving the performance of the device.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a semiconductor device provided in the present application.

Reference signs:

10. Semiconductor device; 100, substrate; 200, light reflection layer; 300, epitaxial layer; 310, P-type doped part; 320, first P-type part; 330, floating diffusion part; 340, first N-type 350, the second P-type part; 360, the second N-type part; 370, the doping part; 400, the polysilicon part.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are only some of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of this application. In the case of no conflict, the following embodiments and technical features thereof can be combined with each other.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

The application provides a semiconductor device, including a substrate, a light reflection layer and an epitaxial layer, the light reflection layer is arranged on the substrate; the epitaxial layer is arranged on the side of the light reflection layer away from the substrate, and the side of the epitaxial layer away from the substrate has The P-type doped part, the first P-type part and the floating diffusion part, the P-type doped part is arranged in contact with the first P-type part, the P-type doped part is in contact with the light reflection layer, and the first P-type part is in contact with the light reflection layer. The layers are arranged at intervals, and the floating diffusion part is located in the first P-type part and arranged at intervals with the P-type doped part.

In this application, by setting a light reflective layer between the epitaxial layer and the substrate, when the light passes through the epitaxial layer, reflection occurs at the interface between the epitaxial layer and the light reflective layer, thereby reflecting the light back into the epitaxial layer , so as to achieve the purpose of reducing the absorption length and reduce the light penetration rate, thereby improving the light conversion efficiency. The possibility of crosstalk between the bottom, thus improving the performance of the device.

Please refer to FIG. 1 , which is a schematic structural diagram of a semiconductor device provided in the present application. The present application provides a semiconductor device 10 . The semiconductor device 10 includes a substrate 100 , a light reflection layer 200 , an epitaxial layer 300 , and a polysilicon portion 400 . The substrate 100 is a silicon substrate 100 . The light reflection layer 200 is disposed on the substrate 100 .

The epitaxial layer 300 is disposed on the side of the light reflection layer 200 away from the substrate 100, and the side of the epitaxial layer 300 away from the substrate 100 has a P-type doped part 310, a first P-type part 320, a floating diffusion part 330, a first N type part 340, the second P-type part 350 and the second N-type part 360, the P-type doped part 310 is arranged in contact with the first P-type part 320 and the light reflection layer 200, and the first N-type part 340 is located in the P-type doped part 310 and the second P-type part 350, and the first N-type part 340 and the second P-type part 350 are both in contact with the first P-type part 320, and the second P-type part 350 is provided with a shallow trench structure , in the direction from the epitaxial layer 300 toward the substrate 100, the projection of the shallow trench structure does not overlap with the projection of the first N-type portion 340, the first P-type portion 320 is spaced apart from the light reflection layer 200, and the floating diffusion portion 330 The second N-type portion 360 is spaced in the first P-type portion 320, and the floating diffusion 330 is spaced from the second P-type portion 350, the P-type doped portion 310, and the first N-type portion 340. The second The N-type portion 360 is located on the side of the floating diffusion portion 330 away from the P-type doped portion 310, the number of the second N-type portion 360 is three, the number of the floating diffusion portion 330 is one, and the second N-type portion 360 is away from the P-type doped portion 310. One side of the floating diffusion part 330 is provided with a doped part 370, the doping concentrations of the first N-type part 340 and the second N-type part 360 are different, and the P-type doped part 310, the first P-type part 320 and the second The doping concentration of the P-type portion 350 is different, and the doping portion 370 is spaced apart from the second N-type portion 360 . The thickness r of the epitaxial layer 300 is 3-4um. Specifically, the thickness r of the epitaxial layer 300 may be 3um, 3.2um, 3.5um, 3.8um, or 4um.

The polysilicon portion 400 is disposed on the side of the epitaxial layer 300 away from the substrate 100 , on the first P-type portion 320 , and is connected to corresponding wires to transmit corresponding signals.

For existing semiconductor devices, if the wavelength of light changes to the non-visible light region, such as infrared light, the existing epitaxial layer design cannot meet the conversion requirements of non-visible light, resulting in poor light conversion efficiency. However, in the present application, by disposing the light reflective layer 200 between the epitaxial layer 300 and the substrate 100, when light passes through the epitaxial layer 300, it is reflected at the interface between the epitaxial layer 300 and the light reflective layer 200, thereby The light is reflected back into the epitaxial layer 300, so as to achieve the purpose of reducing the absorption length, and reduce the light transmittance, thereby improving the light conversion efficiency. At the same time, because most of the light is reflected by the light reflection layer 200, the light irradiation to In the substrate 100, the possibility of light crosstalk between the substrates 100 is reduced, thereby improving the performance of the device.

In this application, by disposing the light reflection layer 200 between the epitaxial layer 300 and the substrate 100, when the wavelength of the light received by the semiconductor device 10 changes, the conversion efficiency of light can be improved without increasing the thickness of the epitaxial layer 300 , and at the same time, the production cost of the device is reduced.

It should be noted that the average distance traveled by a particle when it is injected into a substance to when the particle is absorbed or transformed into other particles is the absorption length.

In one embodiment, the material of the light reflection layer 200 includes at least one of silicon nitride, silicon oxynitride and silicon oxide.

In this application, silicon nitride, silicon oxynitride, and silicon oxide are used to form the light reflection layer 200 to further increase the amount of reflection of light at the interface between the epitaxial layer 300 and the light reflection layer 200, thereby reflecting more light back to the In the epitaxial layer 300 , the absorption length can be further reduced, and the light transmittance can be reduced. At the same time, the possibility of light crosstalk between the substrates 100 can be further reduced, thereby improving the performance of the device.

In one embodiment, the thickness d of the light reflection layer 200 is 400-1000 nm. Specifically, the thickness d of the light reflection layer 200 may be 400 nm, 500 nm, 600 nm, 720 nm, 830 nm or 1000 nm.

In this application, the thickness d of the light reflection layer 200 is set to 400-1000nm to further increase the amount of reflection of light at the interface between the epitaxial layer 300 and the light reflection layer 200, thereby reflecting more light back to the epitaxial layer 300 In order to further reduce the absorption length and reduce the light transmittance, at the same time, further reduce the possibility of light crosstalk between the substrates 100, thereby improving the performance of the device.

In one embodiment, when the thickness d of the light reflection layer 200 is 620nm, the light reflectance of the light reflection layer 200 can reach more than 90%, so as to further reduce the absorption length and reduce the light transmittance. At the same time, And further reduce the possibility of light crosstalk between the substrates 100, thereby improving the performance of the device.

In one embodiment, when the thickness d of the light reflection layer 200 is 750 nm, the light reflectance of the light reflection layer 200 can reach more than 95%, so as to further reduce the absorption length and reduce the light transmittance. At the same time, And further reduce the possibility of light crosstalk between the substrates 100, thereby improving the performance of the device.

In an embodiment, the side of the epitaxial layer 300 is provided with an isolation part, and there may be multiple isolation parts.

In this application, the side of the epitaxial layer 300 is formed as an isolation part to prevent light from leaking from the side of the epitaxial layer 300, thereby achieving the purpose of reducing the absorption length, ensuring the effect of light conversion, and at the same time avoiding the impact of light on other structures , thus ensuring the performance of the device.

In an embodiment, the reflectance of the isolation portion is lower than the reflectance of the light reflection layer 200 , so that the light reflection layer 200 and the isolation portion can increase the light reflectivity while reducing the material cost.

In one embodiment, the isolation part is an ion-doped part. Specifically, by performing ion implantation on the side of the epitaxial layer 300, the ion-doped portion can be N-type doped or P-type doped to form an isolation portion to prevent light from leaking from the side of the epitaxial layer 300, ensuring The effect of light conversion is improved, and at the same time, the light is prevented from affecting other structures, thereby ensuring the performance of the device. .

In an embodiment, the material of the isolation part is insulating material. Specifically, a deep trench is provided on the side of the epitaxial layer 300, and an insulating material is filled in the deep trench. The insulating material includes at least one of silicon nitride, silicon oxynitride, and silicon oxide to form a deep trench that can block light. Groove structure, the material filled in the deep groove is different from the material of the light reflection layer, so as to prevent light from leaking from the side of the epitaxial layer 300, ensuring the effect of light conversion, and at the same time, avoiding the impact of light on other structures, thereby ensuring the device performance.

In one embodiment, the side of the light reflection layer 200 close to the epitaxial layer 300 has several protrusions, the protrusions are used to reflect light, and every two adjacent protrusions can be arranged at intervals or connected, from the direction of the epitaxial layer towards the substrate Above, the shape of the protrusion can be circular, triangular, quadrangular, hexagonal or irregular, etc., which is not limited here.

In the present application, protrusions for reflecting light are provided on the side of the light reflection layer 200 close to the epitaxial layer 300, so that the light can be reflected from multiple angles, so that the light is evenly distributed in the epitaxial layer 300, so as to further improve the performance of the epitaxial layer 300. The light conversion efficiency is high, and the dark current is reduced, thereby improving the performance of the semiconductor device 10 .

In one embodiment, there are several microstructures on the upper surface of the protrusion.

In this application, microstructures are provided on the upper surface of the protrusions to reflect light, so that light can be reflected from multiple angles, so that light can be evenly distributed in the epitaxial layer 300, so as to further improve the light conversion efficiency of the epitaxial layer 300 , and reduce the dark current, thereby improving the performance of the semiconductor device 10 .

The present application provides a semiconductor device 10. A light reflective layer 200 is provided between the epitaxial layer 300 and the substrate 100, so that when light passes through the epitaxial layer 300, it is reflected at the interface between the epitaxial layer 300 and the light reflective layer 200. , so as to reflect the light back into the epitaxial layer 300, so as to achieve the purpose of reducing the absorption length, without increasing the thickness of the epitaxial layer 300, and reducing the light transmittance, thereby improving the light conversion efficiency and reducing the cost.

The above is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process conversion made by using the specification and accompanying drawings of the application, such as the mutual technical characteristics between the various embodiments Combination, or direct or indirect application in other related technical fields, are all included in the scope of patent protection of this application.

Claims (10)

1. A semiconductor device, comprising:

a substrate;

a light reflection layer disposed on the substrate;

the epitaxial layer is arranged on one side, far away from the substrate, of the light reflection layer, one side, far away from the substrate, of the epitaxial layer is provided with a P-type doping part, a first P-type part and a floating diffusion part, the P-type doping part is in contact with the first P-type part, the P-type doping part is in contact with the light reflection layer, the first P-type part is in interval arrangement with the light reflection layer, and the floating diffusion part is located in the first P-type part and is in interval arrangement with the P-type doping part.

2. The semiconductor device according to claim 1, wherein a material of the light reflecting layer includes at least one of silicon nitride, silicon oxynitride, and silicon oxide.

3. The semiconductor device according to claim 1, wherein the thickness of the light reflecting layer is 400 to 1000nm.

4. A semiconductor device according to any one of claims 1-3, characterized in that the side of the epitaxial layer is provided with spacers.

5. The semiconductor device according to claim 4, wherein the isolation portion is an ion doped portion.

6. The semiconductor device according to claim 4, wherein a material of the spacer is an insulating material.

7. A semiconductor device according to any of claims 1-3, characterized in that the thickness of the epitaxial layer is 3-4um.

8. The semiconductor device of any of claims 1-3, further comprising a first N-type portion and a second P-type portion, the first N-type portion being located between the P-type doped portion and the second P-type portion.

9. The semiconductor device of any of claims 1-3, further comprising a second N-type portion in the first P-type portion, the second N-type portion being located on a side of the floating diffusion away from the P-type doping and spaced apart from the floating diffusion.

10. A semiconductor device according to any of claims 1-3, characterized in that the side of the epitaxial layer remote from the substrate is provided with a polysilicon portion, which is located on the first P-type portion.

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