KR-102963420-B1 - Image Sensing Device

Abstract

An image sensing device according to one embodiment of the present invention includes a plurality of unit pixels, wherein each of the plurality of unit pixels includes a photoelectric conversion region formed within a substrate and generating a photocharge from incident light, a control region that generates a Hall current within the substrate, a detection region that captures the photocharge that moves by the Hall current, and a guard ring surrounding the control region, and the Hall current may flow between the control region and the guard ring.

Inventors

• 장재형
• 김종채
• 윤형준

Assignees

• 에스케이하이닉스 주식회사

Dates

Publication Date

20260511

Application Date

20201216

Claims (20)

1. In an image sensing device comprising a plurality of unit pixels, Each of the above plurality of unit pixels is, A photoelectric conversion region formed within a substrate and generating photocharge from incident light; A control region that generates a hole current within the above substrate; A detection region for capturing the photocharge that moves by the hole current; and It includes a guard ring surrounding the above control area, The above Hall current flows between the control region and the guard ring, and A demodulation control signal is applied to the above control area, and The above guard ring includes a first region doped with a P-type conductive impurity and a second region doped with the P-type conductive impurity, and An image sensing device in which the first region has a higher doping concentration of the impurity than the second region, and the doping depth of the substrate in the first region is shallower than the doping depth of the substrate in the second region.
2. In Article 1, The above plurality of unit pixels are arranged in the row direction and column direction of the pixel array, and The above guard ring is an image sensing device that controls the transfer of photocharges between adjacent unit pixels in the row direction and the column direction.
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4. In Article 1, An image sensing device in which the voltage of the above demodulation control signal is a first voltage or a second voltage.
5. In Article 1, The above demodulation control signal is one of the first demodulation control signal, the second demodulation control signal, the third demodulation control signal, and the fourth demodulation control signal, and The first demodulation control signal has a phase difference of 90 degrees with the second demodulation control signal, and The second demodulation control signal has a phase difference of 90 degrees with the third demodulation control signal, and The third demodulation control signal has a phase difference of 90 degrees with the fourth demodulation control signal, and The above-mentioned fourth demodulation control signal is an image sensing device having a phase difference of 90 degrees with the above-mentioned first demodulation control signal.
6. In Article 5, The four adjacent unit pixels mentioned above form a 2x2 matrix structure, and An image sensing device in which the demodulation control signals applied to each of the four unit pixels are different demodulation control signals.
7. In Article 1, An image sensing device in which the detection area surrounds the control area, and the guard ring surrounds the control area.
8. In Article 1, An image sensing device to which a third voltage is applied to the guard ring.
9. In Article 1, The above plurality of unit pixels are each An image sensing device further comprising a drain region for removing photocharges generated within the substrate.
10. In Article 9, A drain transistor is connected to the above drain region, and An image sensing device in which a drain transistor control signal is applied to the drain transistor.
11. In Article 10, The above drain transistor control signal is an image sensing device having a phase difference of 180 degrees with the demodulation control signal applied to the control region.
12. In Article 9, The above guard ring surrounds the above drain area, and The above drain region is an image sensing device positioned between the above control region and the above guard ring.
13. In Article 9, The above drain region is an image sensing device positioned between the above detection region and the above guard ring.
14. In Article 9, An image sensing device in which each of the above unit pixels includes two or more drain regions, and the drain regions share a single drain transistor.
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17. In an image sensing device comprising a plurality of unit pixels, Each of the above plurality of unit pixels is, A tap area including a control area that generates a hole current within a substrate and a detection area that captures photocharges moved by said hole current, and It includes a guard ring surrounding the above tab area, A demodulation control signal for generating the Hall current is applied to the above-mentioned tap area, and The above guard ring controls the transfer of photocharges between the tab regions included in each of the adjacent unit pixels, and An image sensing device in which the depth to which the control region extends into the substrate is smaller than the depth to which the guard ring extends into the substrate.
18. In Article 17, An image sensing device in which four adjacent unit pixels form a 2x2 matrix structure, and the demodulation control signals applied to each of the four unit pixels have different phases.
19. In Article 18, The above demodulation control signal is one of the first demodulation control signal, the second demodulation control signal, the third demodulation control signal, and the fourth demodulation control signal, and The first demodulation control signal has a phase difference of 90 degrees with the second demodulation control signal, and The second demodulation control signal has a phase difference of 90 degrees with the third demodulation control signal, and The third demodulation control signal has a phase difference of 90 degrees with the fourth demodulation control signal, and The above-mentioned fourth demodulation control signal is an image sensing device having a phase difference of 90 degrees with the above-mentioned first demodulation control signal.
20. In Article 19, The first to fourth demodulation control signals are applied to each of the four adjacent tap areas, and An image sensing device in which four adjacent unit pixels each independently perform an electronic detection operation.

Description

Image Sensing Device The present disclosure relates to an image sensing device for detecting the distance to a target object. An image sensing device is a device that captures images by utilizing the light-reactive properties of semiconductors. Recently, with the development of the computer and telecommunications industries, there is increasing demand for image sensing devices with enhanced performance in various fields, including smartphones, digital cameras, game consoles, the Internet of Things, robots, and cameras. Image sensing devices can be broadly classified into CCD (Charge Coupled Device) image sensing devices and CMOS (Complementary Metal Oxide Semiconductor) image sensing devices. CCD image sensing devices have less noise and superior image quality compared to CMOS image sensing devices, but CMOS image sensing devices have a simple driving method and can be implemented with various scanning methods. In addition, CMOS image sensing devices can integrate signal processing circuits onto a single chip through semiconductor manufacturing processes, making product miniaturization easy, power consumption very low, and manufacturing costs low. Recently, CMOS image sensing devices have been gaining attention due to their characteristics that make them more suitable for mobile devices. Demand for image sensing devices that measure depth is surging in sectors such as security, medical equipment, automobiles, gaming consoles, VR/AR, and mobile devices. Representative methods for measuring depth include triangulation, time of flight, and interferometry; among these, the time of flight method offers a wide range of applications, fast processing speeds, and cost advantages. Time of flight (ToF) methods are broadly classified into direct and indirect types; while the principle of calculating distance using incident and reflected light is the same, they are distinguished by the measurement method. The direct method measures distance by calculating round-trip time, while the indirect method measures distance using phase difference. The direct method is advantageous for long-distance measurements and is used in applications such as automobiles, whereas the indirect method is utilized in devices requiring shorter distances and faster processing speeds, such as game consoles and mobile cameras. The indirect method has the advantage of simpler circuitry and being relatively cheaper compared to the direct method. CAPD (Current-Assisted Photonic Demodulator), one of the pixel types of an in-direct ToF sensor, is a method that detects electrons generated inside the pixel using the potential difference of an electric field by applying voltage to a substrate and utilizing the majority current. Because CAPD uses the majority current, it can detect electrons quickly and is also excellent in terms of efficiency as it can detect even electrons formed deep inside the substrate. FIG. 1 is a schematic diagram illustrating the configuration of an image sensing device according to one embodiment of the present invention. FIG. 2 is a simplified diagram showing a pixel array according to one embodiment of the present invention. Figure 3 is a diagram exemplarily showing a unit pixel included in the pixel array illustrated in Figure 2. FIG. 4 is a diagram showing the connection relationship between elements included in a unit pixel and a cross-section cut along the first cutting line of FIG. 3. FIG. 5 is a diagram illustrating the photocharge detection operation of an image sensing device including a guard ring. FIG. 6 is a timing diagram for explaining the operation of an image sensing device according to one embodiment of the present invention. FIG. 7 is a simplified diagram showing a pixel array according to another embodiment of the present invention. FIG. 8 is a diagram showing an example of a unit pixel included in the pixel array illustrated in FIG. 7. FIG. 9 is a diagram showing the connection relationship between elements included in a unit pixel and a cross-section cut along the second cutting line of FIG. 8. Figure 10 is a diagram illustrating the photocharge removal operation in the drain region. FIG. 11 is a timing diagram for explaining the operation of an image sensing device according to another embodiment of the present invention. FIGS. 12 to 13 are drawings for explaining a distance measurement method of an image sensing device according to an embodiment of the present invention. FIGS. 14a to 14c are drawings showing different embodiments of drain areas included in a unit pixel. Hereinafter, various embodiments of the present invention are described with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments and should be understood to include various modifications, equivalents, and/or alternatives of the embodiments of the present invention. FIG. 1 is a schematic diagram illustrating the configuration of an image sensing device (ISD) according to