Image sensing device

Abstract

The present disclosure provides an image sensing device, which includes a plurality of unit pixels, each of which includes a plurality of sub-pixels. Each unit pixel includes: a first isolation portion arranged between sub-pixels adjacent to each other; a second isolation portion formed to surround the sub-pixel; and a voltage application region arranged at a central portion of the unit pixel and configured to receive a first voltage as an input. Each sub-pixel includes: a control region formed to generate a current in a substrate on which the sub-pixel is arranged; and a detection region formed to capture electrons moving with the aid of the current.

Description

Technical Field

[0001] Technologies and embodiments disclosed in the present disclosure generally relate to an image sensing device capable of sensing a distance to a target object. Background Art

[0002] An image sensing device is a device that captures optical images by converting light into electrical signals using photosensitive semiconductor materials that react to light. With the development of the automotive, medical, computer, and communications industries, the demand for high-performance image sensing devices in various fields such as smartphones, digital cameras, game consoles, IoT (Internet of Things), robots, security cameras, and medical micro cameras is increasing.

[0003] Image sensing devices can be roughly divided into CCD (charge coupled device) image sensing devices and CMOS (complementary metal oxide semiconductor) image sensing devices. CCD image sensing devices provide better image quality, but they tend to consume more power and be larger in size than CMOS image sensing devices.

[0004] Compared to CCD image sensing devices, CMOS image sensing devices are smaller in size and consume less power. In addition, CMOS sensors are manufactured using CMOS manufacturing technology, so that photosensitive elements and other signal processing circuits can be integrated into a single chip, thereby enabling miniaturized image sensing devices to be produced at a lower cost. For these reasons, CMOS image sensing devices are being developed for many applications including mobile devices. Summary of the invention

[0005] Various embodiments of the disclosed technology are directed to an image sensing device having a structure optimized for distinguishing detection signals between adjacent sub-pixels.

[0006] According to an embodiment of the disclosed technology, an image sensing device may include: a plurality of unit pixels, wherein each of the unit pixels is configured to generate a photocharge indicating the detected incident light in response to the incident light, and includes: sub-pixels, each sub-pixel including a control area, the control area being configured to generate a current carrying the photocharge within a substrate on which the sub-pixel is arranged; and a detection area, the detection area being separated from the control area and configured to capture the photocharge carried by the current; a plurality of first isolation portions, the first isolation portions being arranged between two adjacent sub-pixels; a second isolation portion, the second isolation portions being arranged to surround the sub-pixels; and a voltage application area, the voltage application area being arranged at a central portion of the unit pixel and configured to receive a first voltage.

[0007] In some implementations, each of the first isolated portion and the second isolated portion is configured to receive a ground voltage that is higher than the first voltage.

[0008] In some implementations, each of the first isolation portions includes: a first doped region having a first depth; a second doped region having a second depth; and a third doped region formed to have a third depth, wherein the sum of the first depth, the second depth, and the third depth is the same as the depth of the substrate.

[0009] In some implementations, the first doping region and the second doping region have different doping densities with respect to each other.

[0010] In some implementations, the second isolation portion includes: a fourth doped region having a fourth depth; a fifth doped region having a fifth depth; and a sixth doped region having a sixth depth, wherein the sum of the fourth depth, the fifth depth, and the sixth depth is the same as the depth of the substrate.

[0011] In some implementations, the fourth doping region and the fifth doping region have different doping densities.

[0012] In some implementations, the control region is configured to receive a demodulated control signal, the demodulated control signal having a second voltage during a first period of time and having a third voltage during a second period of time.

[0013] In some implementations, each of the second voltage and the third voltage is higher than the first voltage.

[0014] In some implementations, the sub-pixels include first to fourth sub-pixels to which different demodulation control signals are applied.

[0015] In some implementations, first to fourth demodulation control signals are applied to first to fourth sub-pixels, respectively, and wherein the first demodulation control signal has a phase difference of 90° relative to the second demodulation control signal, the second demodulation control signal has a phase difference of 90° relative to the third demodulation control signal, the third demodulation control signal has a phase difference of 90° relative to the fourth demodulation control signal, and the fourth demodulation control signal has a phase difference of 90° relative to the first demodulation control signal.

[0016] In some implementations, the detection zone is disposed between the control zone and the second isolation portion.

[0017] In some implementations, the detection zone is arranged to surround the control zone, wherein an opening is arranged between the control zone and the voltage application zone.

[0018] In some implementations, current flows from each of the control region, the first isolation portion, and the second isolation portion to the voltage application region.

[0019] In some implementations, the voltage application region is spaced apart from each of the first isolation portions.

[0020] According to an embodiment of the disclosed technology, an image sensing device may include: sub-pixels arranged in a matrix array, each sub-pixel including a photoelectric conversion region, the photoelectric conversion region being configured to generate photocharges in response to incident light; a first isolation portion, the first isolation portion being arranged to isolate any two adjacent sub-pixels from each other; a second isolation portion, the second isolation portion being arranged along an edge of the sub-pixel; and a voltage application region, the voltage application region being arranged at a central portion of the matrix array and being configured to receive a first voltage as a negative (-) voltage.

[0021] In some implementations, each of the sub-pixels further includes: a detection region configured to capture the photocharges moving along the current; and a control region configured to allow the current to flow to the first isolation portion, the second isolation portion, and the voltage application region.

[0022] In some implementations, the control region is further configured to generate a hole current by receiving a control signal having a second voltage or a third voltage.

[0023] In some implementations, the voltage applying region is arranged to be spaced apart from the first isolation portion and the second isolation portion.

[0024] In some implementations, the first isolated portion and the second isolated portion are coupled to each other.

[0025] In some implementations, a voltage applied to the first isolated portion and the second isolated portion is different from the first voltage.

[0026] It is to be understood that both the foregoing general description and the following detailed description of the disclosed techniques are illustrative and explanatory and are intended to provide further explanation of the disclosure as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other features and advantageous aspects of the disclosed technology will become apparent with reference to the following detailed description when considered in conjunction with the accompanying drawings.

[0028] Figure 1 is a block diagram illustrating an embodiment of an image sensing device based on some implementations of the disclosed technology.

[0029] Figure 2is a schematic diagram showing an embodiment of a pixel array based on some implementations of the disclosed technology.

[0030] Figure 3 is a schematic diagram showing some implementations based on the disclosed technology. Figure 2 The connection relationship between the cross section of the unit pixel taken by the first cutting line shown in FIG. 1 and the constituent circuits connected to the first sub-pixel and the second sub-pixel.

[0031] Figure 4 It shows some implementation methods based on the disclosed technology. Figure 2 A cross-sectional view of an embodiment of a unit pixel taken along the second cutting line shown in FIG.

[0032] Figure 5 is a timing diagram illustrating the operation of an image sensing device based on some other implementations of the disclosed technology.

[0033] Figure 6 is a conceptual diagram showing an embodiment of a voltage to be applied to a unit pixel during an operation time of the unit pixel and a distribution of a potential generated in the operating unit pixel based on some implementations of the disclosed technology.

[0034] Figure 7 and Figure 8 is a conceptual diagram showing an embodiment of a method for forming a first isolation portion and a second isolation portion based on some implementations of the disclosed technology.

[0035] Fig. 9 is a schematic diagram showing an embodiment of a unit pixel with a detection area based on some other implementations of the disclosed technology. DETAILED DESCRIPTION

[0036] The present disclosure provides implementations and embodiments of an image sensing device capable of sensing the distance to a target object. Some implementations of the disclosed technology relate to an image sensing device having a structure optimized for distinguishing detection signals between adjacent sub-pixels. The disclosed technology provides an image sensing device that can allow a control area included in a unit pixel to be surrounded by an isolation portion, thereby improving electronic detection efficiency and reducing signal interference between adjacent sub-pixels. The disclosed technology provides an image sensing device in which a voltage input area is located at the center of each unit pixel, thereby reducing signal interference between adjacent sub-pixels and improving electronic transmission efficiency.

[0037] Hereinafter, various embodiments will be described with reference to the accompanying drawings. However, it should be understood that the disclosed technology is not limited to specific embodiments, but includes various variations, equivalents and / or alternatives of the embodiments. The embodiments of the disclosed technology can provide various effects that can be directly or indirectly recognized by the disclosed technology.

[0038] There have been a lot of developments and research on measuring range and depth (i.e., the distance to a target object) using image sensing devices. For example, in various devices (e.g., security devices, medical equipment, automobiles, game consoles, virtual reality (VR) / augmented reality (AR) devices, mobile devices, etc.), the demand for the above-mentioned depth measurement schemes using image sensors is rapidly increasing. The methods of measuring depth information using one or more image sensors are mainly classified into triangulation methods, time of flight (TOF) methods, and interferometry methods. In more detail, the time of flight (TOF) method in the above-mentioned depth measurement method has more available technical fields, can be processed and operated at higher speeds, and has higher cost-effectiveness, so the TOF method has higher importance.

[0039] TOF methods can be mainly classified into direct methods and indirect methods. Although the principle of calculating the distance to a target object (ie, depth) using emitted light and reflected light is generally applicable to both direct and indirect methods, the direct and indirect methods may have different measurement methods.

[0040] The direct method can calculate the round trip time, and the distance to the target object can be measured using the calculated round trip time. The indirect method can measure the distance to the target object using the phase difference. The direct method has an advantage in long-distance measurement, so the direct method has been widely used in automobiles, etc. The indirect method has an advantage in short-distance measurement, so the indirect method has been widely used in various high-speed devices designed to operate at higher speeds, such as game consoles, portable cameras, etc. The indirect method is simpler in circuit design, so the indirect method can be implemented using relatively low cost.

[0041] The current-assisted photon demodulator (CAPD) method, as any of the pixel types corresponding to the indirect TOF sensor, is a method of detecting electrons that have been generated in a pixel by using a majority carrier current obtained by applying a voltage to a substrate, using a potential difference between electric fields. Thus, since the CAPD method is designed to use the majority carrier current, the CAPD method can detect electrons more quickly and can detect some electrons formed at a deep depth, making the CAPD method super efficient.

[0042] Figure 1 is a block diagram illustrating an embodiment of an image sensing device ISD based on some implementations of the disclosed technology.

[0043] refer to Figure 1 , the image sensing device ISD may measure the distance to the target object 1 using the time of flight (TOF) principle. The image sensing device ISD may include a light source 10, a lens module 20, a pixel array 30, and a control block 40.

[0044] The light source 10 can emit light to the target object 1 upon receiving the light modulation signal MLS from the control block 40. The light source 10 can be a laser diode (LD) or a light emitting diode (LED) for emitting light having a specific wavelength band (e.g., near infrared (NIR) light, infrared (IR) light, or visible light), or can be any one of a near infrared laser (NIR), a point light source, a monochromatic light source combined with a white lamp or a monochromator, and a combination of other laser sources. For example, the light source 10 can emit infrared light having a wavelength of 800 nanometers to 1000 nanometers. The light emitted from the light source 10 can be light modulated at a predetermined frequency (i.e., modulated light). Although Figure 1 For ease of description, only one light source 10 is shown, but the scope or spirit of the disclosed technology is not limited thereto, and a plurality of light sources may also be arranged near the lens module 20 .

[0045] The lens module 20 may collect light reflected from the target object 1 and may allow the collected light to be focused on the pixels (PX) of the pixel array 30. For example, the lens module 20 may include a focusing lens having a surface formed of glass or plastic or other cylindrical optical elements having a surface formed of glass or plastic. The lens module 20 may include a plurality of lenses arranged to focus on the optical axis.

[0046] The pixel array 30 may include unit pixels (PX) arranged continuously in a two-dimensional (2D) matrix structure, in which the unit pixels are arranged in a column direction and a row direction perpendicular to the column direction. The unit pixel (PX) may be a minimum unit repeatedly arranged in the same shape within the pixel array. Each unit pixel may include a plurality of sub-pixels arranged in a matrix array, thereby forming a unit pixel having sub-pixels.

[0047] The unit pixel (PX) may be formed on a semiconductor substrate. Each unit pixel (PX) may convert incident light received through the lens module 20 into an electrical signal corresponding to the amount of incident light, and thus may output a pixel signal using the electrical signal. In this case, the pixel signal may not indicate the color of the target object 1, and may be a signal indicating the distance to the target object 1.

[0048] Each unit pixel (PX) may be a current-assisted photon demodulator (CAPD) pixel. Figure 2The accompanying drawings describe the structure and operation of each unit pixel (PX).

[0049] The control block 40 can emit light to the target object 1 by controlling the light source 10, can process each pixel signal corresponding to the light reflected from the target object 1 by driving the unit pixel (PX) of the pixel array 30, and can measure the distance to the surface of the target object 1 using the processing result.

[0050] The control block 40 may include a row driver 41 , a demodulation driver 42 , a light source driver 43 , a timing controller 44 , and a readout driver 45 .

[0051] The row driver 41 may drive the unit pixel (PX) of the pixel array in response to the timing signal generated from the timing controller 44. For example, the row driver 41 may generate a control signal capable of selecting and controlling at least one row line from a plurality of row lines. The control signal may include a reset signal RST for controlling a reset transistor, a transmission signal TRG for controlling the transfer of photocharges accumulated in a detection region, a floating diffusion signal FDG for providing additional electrostatic capacity at a high illumination level, a selection signal SEL for controlling a selection transistor, and the like.

[0052] Although for ease of description Figure 1 The row driver 41 is shown arranged in the column direction (ie, vertical direction) of the pixel array 30 , but at least some parts of the row driver 41 may be arranged in the row direction (ie, horizontal direction) of the pixel array 30 .

[0053] The demodulation driver 42 may generate a demodulation control signal that can be applied to at least one of the plurality of sub-pixels in response to a timing signal generated from the timing controller 44. The demodulation control signal may generate a potential difference in the substrate. The potential difference generated in the substrate may generate a hole current for moving electrons of the substrate.

[0054] The light source driver 43 may generate a light modulation signal MLS capable of driving the light source 10 in response to a control signal from the timing controller 44. The light modulation signal MLS may be a signal modulated at a predetermined frequency.

[0055] The timing controller 44 may generate timing signals to control the row driver 41 , the demodulation driver 42 , the light source driver 43 , and the readout driver 45 .

[0056] The readout driver 45 may process the pixel signal received from the pixel array 30 under the control of the timing controller 44, and may thus generate pixel data formed in the shape of a digital signal. To this end, the readout driver 45 may include a correlated double sampler (CDS) circuit for performing correlated double sampling (CDS) on the pixel signal generated from the pixel array 30.

[0057] In addition, the readout driver 45 may include an analog-to-digital converter (ADC) for converting an output signal of the CDS circuit into a digital signal. In addition, the readout driver 45 may include a buffer circuit that temporarily stores pixel data generated from the analog-to-digital converter (ADC) and outputs the pixel data under the control of the timing controller 44. Meanwhile, since the pixel array 30 includes CAPD pixels, two column lines for transmitting pixel signals may be allocated to each column of the pixel array 30, and a structure for processing a pixel signal generated from each column line may be configured to correspond to the corresponding column line.

[0058] The light source 10 may emit light modulated at a predetermined frequency (i.e., modulated light) to a scene captured by the image sensing device ISD. The image sensing device ISD may sense the modulated light (i.e., incident light) reflected from the target object 1 included in the scene, and may thus generate depth information for each unit pixel (PX).

[0059] A time delay may occur between the modulated light and the incident light based on the distance between the image sensing device ISD and each target object 1. The time delay may be represented by a phase difference between a signal generated by the image sensing device ISD and a light modulation signal MLS controlling the light source 10. An image processor (not shown) may calculate the phase difference generated in the output signal of the image sensing device ISD, and may thus generate a depth image.

[0060] Figure 2 is a schematic diagram showing an embodiment of a pixel array 30 based on some implementations of the disclosed technology.

[0061] although Figure 2 The pixel array 30 is shown to include four unit pixels arranged in a matrix array including two rows and two columns, but other implementations are also possible. Therefore, the pixel array 30 may include any number of unit pixels (eg, the pixel array 30 may include N unit pixels), where N is a positive integer.

[0062] Each unit pixel (PX) may include first to fourth sub-pixels SP1 to SP4. The unit pixels (PX) may be substantially identical to each other in structure, so the following description will focus on the structure of the first to fourth sub-pixels SP1 to SP4. Figure 2 , a unit pixel (PX) located at a first row and a first column position in a matrix array including unit pixels (PX) is shown.

[0063] Each unit pixel (PX) may include: first to fourth sub-pixels SP1 to SP4; one or more first isolation portions 110 arranged between any two adjacent sub-pixels; a second isolation portion 120 formed to surround adjacent sub-pixels; and a voltage application region 150 located at the center of the unit pixel (PX).

[0064] In some implementations, the first isolation portion 110 can be arranged between any two adjacent sub-pixels, for example, between a first sub-pixel SP1 and a second sub-pixel SP2 that are adjacent to each other, between a second sub-pixel SP2 and a third sub-pixel SP3 that are adjacent to each other, between a third sub-pixel SP3 and a fourth sub-pixel SP4 that are adjacent to each other, and / or between a first sub-pixel SP1 and a fourth sub-pixel SP4 that are adjacent to each other.

[0065] The second isolation portion 120 may be arranged along the edge of the sub-pixel of the unit pixel. The second isolation portion 120 may be formed to surround the sub-pixels (eg, SP1 to SP4) of the unit pixel. Figure 2 In the embodiment of the present invention, the unit pixel includes four adjacent sub-pixels (e.g., SP1 to SP4) that form a (2×2) matrix array. The second isolation portion 120 may be arranged to isolate the sub-pixels of adjacent unit pixels. The sub-pixels of a unit pixel (PX) may be isolated from the sub-pixels of another unit pixel (PX) by means of the second isolation portion 120.

[0066] The first isolation portion 110 and the second isolation portion 120 may be coupled to each other. In some implementations, the first isolation portion 110 and the second isolation portion 120 may be formed simultaneously by an impurity implantation process. In some implementations, the same voltage may be applied to the first isolation portion 110 and the second isolation portion 120. In some implementations, the first isolation portion 110 and the second isolation portion 120 may be physically connected to each other.

[0067] The flow of electrons between adjacent sub-pixels may be controlled in response to a voltage applied to the first isolation portion 110. For example, by applying a voltage to the first isolation portion 110 and allowing current to flow between the control region 140 and the first isolation portion 110, current flowing between the control regions 140 respectively included in adjacent sub-pixels SP1 to SP4 may be reduced.

[0068] In addition, the movement of electrons between adjacent unit pixels may be controlled in response to a voltage applied to the second isolation portion 120. For example, by applying a voltage to the second isolation portion 120 and allowing current to flow between the second isolation portion 120 and the control region 140, current flowing between the control regions 140 respectively included in adjacent unit pixels (PX) may be reduced.

[0069] By using the first isolation portion 110 and the second isolation portion 120 , noise generated by electron movement between adjacent sub-pixels SP1 to SP4 or adjacent unit pixels (PX) may be reduced.

[0070] The voltage applying region 150 may be disposed at the center of each unit pixel (PX). The center of the unit pixel (PX) may be located at the same distance from the center of each of the first to fourth subpixels SP1 to SP4 included in each unit pixel (PX).

[0071] The voltage applying region 150 may be spaced apart from the first isolation portion 110. Since the voltage applying region 150 is spaced apart from the first isolation portion 110, different voltages may be applied to the voltage applying region 150 and the first isolation portion 110.

[0072] Each of the first to fourth sub-pixels SP1 to SP4 may include a detection region 130 and a control region 140, the structures of which are designed to be conductive and can be used to receive a voltage signal to be electrically biased to capture electrons in each sub-pixel. In this case, the detection region 130 may be arranged between the control region 140 and the second isolation portion 120, and may receive a detection voltage.

[0073] The detection region 130 may capture electrons moving along a current flowing between the control region 140 and the voltage application region 150 , a current flowing between the control region 140 and the second isolation portion 120 , and / or a current flowing between the control region 140 and the first isolation portion 110 .

[0074] Demodulation control signals having different phase differences may be applied to the control areas 140 respectively included in the first to fourth subpixels SP1 to SP4. Each demodulation control signal may be a signal having an activation voltage during a first time period or a deactivation voltage during a second time period. The demodulation control signal may have the same phase difference as the modulated light, or may have a predetermined phase difference relative to the modulated light.

[0075] The four sub-pixels SP1 to SP4 included in the unit pixel (PX) may detect electrons corresponding to incident light incident at a time point when a demodulation control signal applied to each of the sub-pixels SP1 to SP4 has an activation voltage with respect to the incident light.

[0076] Figure 3 is a schematic diagram showing some implementations based on the disclosed technology. Figure 2 1 and 2 , and shows a connection relationship between a cross section of a unit pixel (PX) taken along a first cutting line AA′ and constituent circuits connected to the first sub-pixel SP1 and the second sub-pixel SP2.

[0077] The following will refer to Figure 2 The structure and operation of the unit pixel (PX) are described with reference to a cross section of the unit pixel (PX) taken along the first cutting line AA′ shown in FIG. 1 and a circuit connected to the unit pixel (PX).

[0078] Apart from Figure 2 In addition to the first isolation portion 110, the second isolation portion 120, the detection area 130, the control area 140 and the voltage application area 150 shown in FIG. Figure 3 The unit pixel (PX) shown in FIG. 1 may further include a photoelectric conversion region 160 and a passivation layer 170 .

[0079] The region where the first isolation part 110, the second isolation part 120, the detection region 130, the control region 140, the voltage applying region 150, the photoelectric conversion region 160 and the passivation layer 170 are located will hereinafter be referred to as the sensing region 300. Electrons corresponding to incident light may be generated in the sensing region 300.

[0080] The first isolation portion 110, the second isolation portion 120, the detection area 130, the control area 140, and the passivation layer 170 may be formed on a semiconductor substrate or an epitaxial layer. For example, the semiconductor substrate may refer to a silicon wafer, and the epitaxial layer may refer to a crystal growth layer formed on the silicon wafer. Therefore, the sensing area 300 may be formed on a semiconductor substrate, and light (i.e., incident light) may be incident on one surface of the semiconductor substrate. In this case, the surface on which the light is incident will be referred to as a light receiving surface hereinafter.

[0081] Each of the first isolation portion 110 , the second isolation portion 120 , the detection region 130 , and the control region 140 may be formed to have a predetermined depth relative to a surface of the semiconductor substrate or the epitaxial layer facing or opposite to a light receiving surface of incident light.

[0082] The second isolation portion 120 may be formed to have the same depth as the semiconductor substrate or epitaxial layer so that the photoelectric conversion regions 160 included in adjacent unit pixels (PX) may be physically isolated from each other. In addition, the first isolation portion 110 and the second isolation portion 120 may be formed to have the same depth.

[0083] The first isolation portion 110 and the second isolation portion 120 may be doped with the same impurities. For example, the first isolation portion 110 and the second isolation portion 120 may be doped with P-type impurities.

[0084] The first isolation portion 110 and the second isolation portion 120 may include a plurality of doping regions with different impurity densities. For example, the first isolation portion 110 may include a first doping region 112, a second doping region 114, and a third doping region 116. In addition, the second isolation portion 120 may include a fourth doping region 122, a fifth doping region 124, and a sixth doping region 126.

[0085] The first doping region 112 may be doped at a higher density than each of the second doping region 114 and the third doping region 116. The second doping region 114 may be doped at a higher density than the third doping region 116, or may be doped at the same density as the third doping region 116. Each of the first doping region 112, the second doping region 114, and the third doping region 116 may be doped with P-type impurities.

[0086] The fourth doping region 122 may be doped at a higher density than each of the fifth doping region 124 and the sixth doping region 126. The fifth doping region 124 may be doped at a higher density than the sixth doping region 126, or may be doped at the same density as the sixth doping region 126. Each of the fourth doping region 122, the fifth doping region 124, and the sixth doping region 126 may be doped with P-type impurities.

[0087] The plurality of doping regions included in the first isolation portion 110 and the plurality of doping regions included in the second isolation portion 120 may be formed by the same process according to doping concentration (density). For example, the third doping region 116 included in the first isolation portion 110 may be formed by the same ion implantation process as the sixth doping region 126 included in the second isolation portion 120. In some implementations, the first doping region 112 may be formed by the same ion implantation process as the fourth doping region 122, and the second doping region 114 may be formed by the same ion implantation process as the fifth doping region 124.

[0088] The depth of the first doping region 112 in the substrate may be referred to as a first depth. In addition, the depth of the second doping region 114 in the substrate may be referred to as a second depth. The depth of the third doping region 116 in the substrate may be referred to as a third depth.

[0089] The first depth may refer to a depth measured in a direction from a surface facing or opposite to a light receiving surface of incident light to a boundary between the first doping region 112 and the second doping region 114. The second depth may refer to a depth measured in a direction from a boundary between the first doping region 112 and the second doping region 114 to a boundary between the second doping region 114 and the third doping region 116. The third depth may refer to a depth measured in a direction from a boundary between the second doping region 114 and the third doping region 116 to a boundary between the third doping region 116 and the passivation layer 170. Therefore, the sum of the first to third depths may be equal to the thickness of the semiconductor substrate or the thickness of the epitaxial layer.

[0090] The depth of the fourth doping region 122 in the substrate may be referred to as a fourth depth. In addition, the depth of the fifth doping region 124 in the substrate may be referred to as a fifth depth. The depth of the sixth doping region 126 in the substrate may be referred to as a sixth depth.

[0091] The fourth depth may refer to a depth measured in a direction from a surface facing or opposite to a light receiving surface of incident light to a boundary between the fourth doping region 122 and the fifth doping region 124. The fifth depth may refer to a depth measured in a direction from a boundary between the fourth doping region 122 and the fifth doping region 124 to a boundary between the fifth doping region 124 and the sixth doping region 126. The sixth depth may refer to a depth measured in a direction from a boundary between the fifth doping region 124 and the sixth doping region 126 to a boundary between the sixth doping region 126 and the passivation layer 170. Therefore, the sum of the fourth to sixth depths may be equal to the thickness of the semiconductor substrate or the thickness of the epitaxial layer.

[0092] In some implementations, the first depth can be the same as the fourth depth, and the second depth can be the same as the fifth depth. In addition, the third depth can be the same as the sixth depth.

[0093] As mentioned earlier, the ground voltage (V GND ) may be applied to the first isolation portion 110 and the second isolation portion 120. For example, a ground voltage (V GND ) can be zero volts (0V). The ground voltage (V GND ) may be applied to the first doping region 112 and the fourth doping region 122 .

[0094] The detection area 130 and the control area 140 may be included in each of the sub-pixels SP1 to SP4 included in the unit pixel (PX). Figure 2 As can be seen from the cross section of the unit pixel taken along the first cutting line AA′ shown in FIG. 1 , each of the first sub-pixel SP1 and the second sub-pixel SP1 may include a detection area 130 and a control area 140 .

[0095] The detection region 130 may be doped with impurities different from those of the first isolation portion 110 and the second isolation portion 120. For example, the detection region 130 may be doped with N-type impurities.

[0096] The detection region 130 may include a plurality of doping regions having different impurity densities. For example, the detection region 130 may include a seventh doping region 132 and an eighth doping region 134. The density of the seventh doping region 132 may be higher than the density of the eighth doping region 134. The seventh depth formed in the substrate by the seventh doping region 132 may be less than the eighth depth formed in the substrate by the eighth doping region 134.

[0097] The seventh depth may refer to a depth measured in a direction from a surface facing or opposite to a light receiving surface of incident light to a boundary between the seventh doping region 132 and the eighth doping region 134. The eighth depth may refer to a depth measured in a direction from a boundary between the seventh doping region 132 and the eighth doping region 134 to a boundary between the eighth doping region 134 and the photoelectric conversion region 160.

[0098] The detection region 130 may receive a detection voltage as an input. A plurality of circuits may be coupled to the detection region 130 so that the detection region 130 may process the collected electrons and convert the electrons into electrical signals. A plurality of circuits may be formed in each of the sub-pixels (eg, SP1 and SP2) that respectively include the detection region 130.

[0099] The control region 140 may be doped with the same impurities as the first isolation portion 110 and the second isolation portion 120. For example, the control region 140 may be doped with P-type impurities.

[0100] The control region 140 may include a plurality of doping regions having different impurity densities. For example, the control region 140 may include a ninth doping region 142 and a tenth doping region 144 .

[0101] The density of the ninth doping region 142 may be higher than that of the tenth doping region 144. The ninth doping region 142 may be formed at a ninth depth in the substrate less than the tenth doping region 144 is formed at a tenth depth in the substrate.

[0102] The ninth depth may refer to a depth measured in a direction from a surface facing or opposite to a light receiving surface of incident light to a boundary between the ninth doping region 142 and the tenth doping region 144. The tenth depth may refer to a depth measured in a direction from a boundary between the ninth doping region 142 and the tenth doping region 144 to a boundary between the tenth doping region 144 and the photoelectric conversion region 160.

[0103] The demodulation control signals V corresponding to the sub-pixels SP1 to SP4 are CS1 To V CS4 The control area 140 may be applied to the sub-pixels SP1 to SP4. As described above, the demodulated control signal V CS1 To V CS4 There can be different phase differences.

[0104] For example, the first demodulation control signal (V CS1 ) may be applied to the control area 140 included in the first sub-pixel SP1, and the second demodulation control signal (V CS2 ) may be applied to the control area 140 included in the second sub-pixel SP2, and the third demodulation control signal (V CS3) may be applied to the control area 140 included in the third sub-pixel SP3, and the fourth demodulation control signal (V CS4 ) may be applied to the control region 140 included in the fourth sub-pixel SP4.

[0105] Demodulation control signal V CS1 To V CS4 Each of the second voltages (V 2 ) and the third voltage (V 3 ) is repeatedly applied to the control area 140 at predetermined time intervals.

[0106] The second voltage (V 2 ) may refer to a voltage generated when current occurs between the control area 140 included in each of the sub-pixels SP1 to SP4 and the first isolation portion 110, between the control area 140 included in each of the sub-pixels SP1 to SP4 and the second isolation portion 120, and / or between the control area 140 included in each of the sub-pixels SP1 to SP4 and the voltage application area 150.

[0107] The above current may be referred to as Hall current. As the Hall current is generated, the detection region 130 adjacent to the control region 140 may capture electrons. For example, the second voltage (V 2 ) may be 1.2 volts (1.2V). 2 )'s logic value of the demodulation driver 42 may be at a logic high level (H).

[0108] The third voltage (V 3 ) may refer to a voltage generated when no current flows between the control region 140 included in each of the sub-pixels SP1 to SP4 and the first isolation portion 110 and / or between the control region 140 included in each of the sub-pixels SP1 to SP4 and the second isolation portion 120. For example, the third voltage (V 3 ) can refer to the ground voltage (V GND ). It is used to apply the third voltage (V 3 )'s logic value of the demodulation driver 42 may be at a logic low level (L).

[0109] Each demodulation control signal can allow the second voltage (V 2 ) and the third voltage (V 3 ) is applied to the control zone 140 at predetermined time intervals.

[0110] Will refer to it later Figure 5 Demodulation control signals applied to sub-pixels respectively are described.

[0111] The photoelectric conversion region 160 may be arranged for the sub-pixels SP1 to SP4 included in the unit pixel (PX).

[0112] The photoelectric conversion region 160 may be arranged to occupy as large a space as possible to improve light receiving efficiency (Rx) of the unit pixel (PX).

[0113] The photoelectric conversion region 160 may receive incident light, and may generate electrons corresponding to the received incident light.

[0114] The detection region 130 may capture electrons corresponding to the received light and may thereby generate a phase signal.

[0115] Since the first isolation portion 110 is formed to be spaced apart from the voltage applying region 150 , the photoelectric conversion region 160 included in one unit pixel (PX) may not be completely isolated for each sub-pixel.

[0116] The second isolation portion 120 may be formed to surround sub-pixels (eg, SP1 to SP4) included in each unit pixel (PX) and may be formed to have the same depth as the substrate or epitaxial layer so that the photoelectric conversion regions 160 included in adjacent unit pixels (PX) may be isolated from each other.

[0117] The passivation layer 170 may be formed by doping P-type impurities on a semiconductor substrate or an epitaxial layer.

[0118] The ground voltage (V GND ) is applied to the passivation layer 170. For example, a ground voltage (V GND ) can be zero volts (0V). Since the ground voltage (V GND ) is applied to the passivation layer 170, so current can flow between the passivation layer 170 and the control region 140 that receives the activation voltage.

[0119] For the sub-pixels SP1 to SP4 included in the unit pixel (PX), a region in which a plurality of circuits connected to the detection region 130 of the respective sub-pixels SP1 to SP4 are arranged will hereinafter be referred to as a circuit region 310 .

[0120] Figure 3 An embodiment of a plurality of circuits connected to each of the detection areas 130 included in the first sub-pixel SP1 and the second sub-pixel SP2 , respectively, is shown.

[0121] The circuit area 310 may include a plurality of circuits to process the electrons captured by the detection area. The control signals RST, TRG, FDG, and SEL may be received from the row driver 41. In addition, the pixel voltage (V px ) can be the power supply voltage (VDD) or the source voltage (VSS).

[0122] although Figure 2 Although not shown in the figure, the circuit area 310 can be arranged between the unit pixels (PX). Alternatively, in some other implementations, the circuit area 310 can be formed to overlap with the unit pixel (PX). The position of the circuit area 310 can be changed according to the layout structure of such pixels, but is not limited thereto.

[0123] First, a circuit for processing electrons captured by the detection region 130 included in the first sub-pixel SP1 will be described in detail below.

[0124] The circuit area 310 may include a reset transistor RX_1 , a transfer transistor TX_1 , a first capacitor C1_1 , a second capacitor C2_1 , a floating diffusion transistor FDX_1 , a drive transistor DX_1 , and a select transistor SX_1 .

[0125] The reset transistor RX_1 may be activated in response to a logic high level of a reset signal RST supplied to a gate thereof, so that the potential of the floating diffusion area FD_1 and the potential of the detection area 130 may be reset to a predetermined level (eg, the pixel voltage V px ). In addition, when the reset transistor RX_1 is activated (ie, active state), the transfer transistor TX_1 may also be activated (ie, active state) to reset the floating diffusion area FD_1.

[0126] The transfer transistor TX_1 may be activated (ie, an active state) in response to a logic high level of a transfer signal TRG supplied to a gate thereof, so that electrons accumulated in the detection region 130 may be transferred to the floating diffusion region FD_1 .

[0127] The first capacitor C1_1 may be coupled to the floating diffusion region (FD_1) such that the first capacitor C1_1 may provide a predetermined electrostatic capacity.

[0128] The second capacitor C2_1 may be selectively coupled to the floating diffusion area FD_1 according to the operation of the floating diffusion transistor FDX_1 , so that the second capacitor C2_1 may provide an additional predetermined electrostatic capacity.

[0129] Each of the first capacitor C1_1 and the second capacitor C2_1 may include, for example, at least one of a metal-insulator-metal (MIM) capacitor, a metal-insulator-polysilicon (MIP) capacitor, a metal-oxide-semiconductor (MOS) capacitor, and a junction capacitor.

[0130] The floating diffusion transistor FDX_1 may be activated (ie, active state) in response to a logic high level of a floating diffusion signal FDG supplied to a gate thereof, so that the floating diffusion transistor FDX_1 may couple the second capacitor C2_1 to the floating diffusion area FD_1 .

[0131] For example, when the amount of incident light is sufficient to correspond to a relatively high illumination condition, the row driver 41 may activate the floating diffusion transistor FDX_1 so that the floating diffusion transistor FDX_1 enters an activated state and the floating diffusion area FD_1 may be coupled to the second capacitor C2_1. Therefore, when the amount of incident light is sufficient to correspond to a high illumination level, the floating diffusion area FD_1 may accumulate more photocharges therein, which enables a high dynamic range (HDR) to be ensured.

[0132] When the amount of incident light is insufficient and thus corresponds to a relatively low illumination level, the row driver 41 may control the floating diffusion transistor FDX_1 to be deactivated (ie, inactive state) so that the floating diffusion area FD_1 may be isolated from the second capacitor C2_1 .

[0133] In some other implementations, the floating diffusion transistor FDX_1 and the second capacitor C2_1 may be omitted as desired.

[0134] The drain of the driving transistor DX_1 is coupled to the pixel voltage (Vpx), and the source of the driving transistor DX_1 is coupled to the vertical signal line SL_1 by means of the selection transistor SX_1, so that the load (MOS) and the source follower circuit of the constant current source circuit CS_1 coupled to one end of the vertical signal line SL_1 can be configured. Therefore, the driving transistor DX_1 can output a current corresponding to the potential of the floating diffusion area FD_1 coupled to the gate of the driving transistor DX_1 to the vertical signal line SL_1 through the selection transistor SX_1.

[0135] The selection transistor SX_1 may be activated (ie, an active state) in response to a logic high level of a selection signal SEL supplied to a gate thereof, so that a pixel signal generated from the driving transistor DX_1 may be output to the vertical signal line SL_1 .

[0136] To process electrons captured by the detection region 130 included in the second subpixel SP2 , the circuit region 310 may include a reset transistor RX_2 , a transfer transistor TX_2 , a first capacitor C1_2 , a second capacitor C2_2 , a floating diffusion transistor FDX_2 , a drive transistor DX_2 , and a select transistor SX_2 .

[0137] Although the circuit for processing electrons captured by the detection area 130 included in the second subpixel SP2 may operate at a different time point from other circuits for processing electrons captured by the detection area 130 included in the first subpixel SP1, the circuit for processing electrons captured by the detection area 130 included in the second subpixel SP2 may be substantially the same in structure and operation as other circuits for processing electrons captured by the detection area 130 included in the first subpixel SP1. Therefore, for ease of description, a detailed description of the structure and operation will be omitted here.

[0138] Pixel signals transmitted from the circuit area 310 to the vertical signal line SL_1 and pixel signals transmitted from the circuit area 310 to the vertical signal line SL_2 may be subjected to noise removal and analog-to-digital (ADC) conversion processing so that each pixel signal may be converted into image data.

[0139] although Figure 3 Each of the reset signal RST, transfer signal TRG, floating diffusion signal FDG, and selection signal SEL shown in FIG. 1 is represented by a single signal line, but each of the reset signal RST, transfer signal TRG, floating diffusion signal FDG, and selection signal SEL may be supplied through a plurality of signal lines (e.g., two signal lines). In this case, a circuit for processing electrons captured by the detection area 130 included in the first sub-pixel SP1 and other circuits for processing electrons captured by the detection area 130 included in the second sub-pixel SP2 may operate at different time points based on signals supplied via the plurality of signal lines.

[0140] An image processor (not shown) can calculate first image data obtained from electrons captured by the first subpixel SP1, second image data obtained from electrons captured by the second subpixel SP2, third image data obtained from electrons captured by the third subpixel (not shown), and fourth image data obtained from electrons captured by the fourth subpixel (not shown), thereby calculating the phase difference using the first to fourth image data.

[0141] Figure 4 It shows some implementation methods based on the disclosed technology. Figure 2 FIG. 1 is a cross-sectional view of an embodiment of a unit pixel (PX) taken along a second cutting line BB′ shown in FIG.

[0142] Already referenced Figure 3 The circuit area ( Figure 3 310) and connected to the circuit area ( Figure 3 310) detection area 130, so for ease of description, here will be Figure 4 The circuit area is omitted ( Figure 3Although not shown in the figure, it should be noted that the circuit for processing the captured electrons can also be connected to the detection area 130 included in the third sub-pixel SP3.

[0143] Already referenced Figure 2 and Figure 3 The second isolation portion 120, the detection region 130, the control region 140, the photoelectric conversion region 160 and the passivation layer 170 are described, so here we will start from Figure 4 Its detailed description is omitted.

[0144] although Figure 4 For the convenience of description, a cross-sectional view of a unit pixel taken along a line from the first subpixel SP1 to the third subpixel SP3 is shown, but the scope or spirit of the disclosed technology is not limited thereto, and other cross-sectional views of the unit pixel taken along a line from the second subpixel SP2 to the fourth subpixel SP4 may be similar to those of FIG. Figure 4 Basically the same.

[0145] As from Figure 4 It can be seen that the photoelectric conversion region 160 can be formed as one region in the entirety of the sub-pixels (eg, SP1 and SP3).

[0146] The voltage applying region 150 may be formed at the center of the unit pixel (PX). In this case, the center of the unit pixel (PX) may refer to a position spaced the same distance from the control regions 140 respectively included in the four adjacent sub-pixels SP1 to SP4.

[0147] The voltage applying region 150 may be doped with the same impurities as the first isolation portion 110 and the second isolation portion 120. For example, the voltage applying region 150 may be doped with P-type impurities.

[0148] The voltage applying region 150 may include a plurality of doping regions having different impurity densities. For example, the voltage applying region 150 may include an eleventh doping region 152 and a twelfth doping region 154 .

[0149] The density of the eleventh doping region 152 may be higher than the density of the twelfth doping region 154. The eleventh doping region 152 may be formed to an eleventh depth in the substrate less than the twelfth doping region 154 may be formed to a twelfth depth in the substrate.

[0150] The eleventh depth may refer to a depth measured in a direction from a surface facing or opposite to a light receiving surface of incident light to a boundary between the eleventh doping region 152 and the twelfth doping region 154. The twelfth depth may refer to a depth measured in a direction from a boundary between the eleventh doping region 152 and the twelfth doping region 154 to a boundary between the twelfth doping region 154 and the photoelectric conversion region 160.

[0151] The first voltage (V 1 ) is applied to the voltage application region 150. The first voltage (V 1 ) may be lower than the second voltage (V 2 ) and the third voltage (V 3 ). For example, the first voltage (V 1 ) can be set to -0.2V to -0.5V.

[0152] When the first voltage (V 1 ) is applied to the voltage application region 150, current can flow between the voltage application region 150 and the control region 140. 1 ) and a second voltage (ie, activation voltage V 2 ) increases, and current can easily flow between the voltage application area 150 and the control area 140.

[0153] Electrons generated by the photoelectric conversion region 160 can move by means of a current flowing between the voltage application region 150 and the control region 140. 2 ) is applied to the control region 140, the electrons generated by the photoelectric conversion region 160 can move from the voltage application region 150 to the receiving region 150 to receive the second voltage (V 2 ) control area 140.

[0154] Detection voltage (V DR ) may be applied to the detection region 130. As described above, the detection voltage (V DR ) can be higher than the second voltage (V 2 ). When the detection voltage (V DR ) is applied to the detection zone 130, electrons moving along the current flowing between the voltage application zone 150 and the control zone 140 can be detected in the detection zone 130.

[0155] In addition, in some implementations, the detection zone 130 may not be formed between the voltage application zone 150 and the control zone 140. If the detection zone 130 is formed between the voltage application zone 150 and the control zone 140, the flow of electrons between the voltage application zone 150 and the control zone 140 may be interrupted by the detection voltage applied to the detection zone 130.

[0156] If the first voltage (V 1 ) is lower than the third voltage (V 3 ), then even when the third voltage (V 3 ) is applied to the control area 140, current can also flow between the control area 140 and the voltage application area 150.

[0157] However, upon receiving the third voltage (V 3 The intensity of the current flowing between the control area 140 and the voltage application area 150 may be smaller than that when receiving the second voltage (V 2 )'s intensity of the current flowing between the control area 140 and the voltage application area 150.

[0158] The signal corresponding to the electrons captured by the first sub-pixel SP1 may be referred to as a first sub-pixel signal. Likewise, the signal corresponding to the electrons captured by the third sub-pixel SP3 may be referred to as a third sub-pixel signal.

[0159] The first sub-pixel signal and the third sub-pixel signal may be demodulation control signals (eg, V CS1 and V CS3 ). An image processor (not shown) may generate phase data based on pixel signals detected by the sub-pixels SP1 to SP4.

[0160] Figure 5 is a timing diagram showing the operation of an image sensing device ISD based on some other implementations of the disclosed technology.

[0161] Figure 5 The modulated light (ML), the incident light (IL) and the first demodulation control signal V CS1 To the fourth demodulation control signal V CS4 .

[0162] For sub-pixels (eg, SP1 to SP4 ) included in one unit pixel (PX), the sub-pixels to which demodulation control signals having the same phase are applied may be arranged at the same position in the unit pixel (PX) of the pixel array 30 .

[0163] For ease of description, the following will refer to Figure 5 Description applies to the Figure 2 The first demodulation control signal V of the sub-pixels SP1 to SP4 in the unit pixel (PX) shown in FIG. CS1 To the fourth demodulation control signal V CS4 .

[0164] The first demodulation control signal V CS1 To the fourth demodulation control signal V CS4 The voltages may be generated by the demodulation driver 42 and may be applied to the control areas 140 respectively included in the sub-pixels (eg, SP1 to SP4).

[0165] The first demodulation control signal V with different phase differences CS1 To the fourth demodulation control signal V CS4 The demodulation control signal VCS1 To V CS4 Each of may have the same phase as the modulated light, and may have a predetermined phase difference relative to the modulated light.

[0166] For example, the demodulation control signal (V CS1 ) may be applied to the first sub-pixel SP1. In addition, a demodulation control signal (V CS2 ) may be applied to the second sub-pixel SP2. A demodulation control signal (V CS3 ) may be applied to the third sub-pixel SP3. In addition, a demodulation control signal (V CS4 ) may be applied to the fourth sub-pixel SP4.

[0167] The first demodulation control signal (V CS1 ) can be used to periodically increase the second voltage (V 2 ) and the third voltage (V 3 ) is applied to the signal of the control area 140 of the first sub-pixel SP1.

[0168] Similarly, the second demodulation control signal (V CS2 ) can be used to periodically increase the second voltage (V 2 ) and the third voltage (V 3 ) applied to Figure 2 In addition, the third demodulated control signal (V CS3 ) can be used to periodically increase the second voltage (V 2 ) and the third voltage (V 3 ) applied to Figure 2 The fourth demodulated control signal (V CS4 ) can be used to periodically increase the second voltage (V 2 ) and the third voltage (V 3 ) applied to Figure 2 The signal of the control area 140 of the fourth sub-pixel SP4 is shown in FIG.

[0169] The first sub-pixel SP1 can detect the first demodulation control signal (V CS1 ) has a second voltage (V 2 ). The second sub-pixel SP2 can detect the electrons corresponding to the incident light received at the time point of the second demodulation control signal (V CS2 ) has a second voltage (V 2) time point. The third sub-pixel SP3 can detect the electrons corresponding to the incident light received at the third demodulation control signal (V CS3 ) has a second voltage (V 2 ) received at the time point of the incident light. The fourth sub-pixel SP4 can detect the electrons corresponding to the incident light received at the time point of the fourth demodulation control signal (V CS4 ) has a second voltage (V 2 ) corresponds to the electron corresponding to the incident light received at the time point.

[0170] For example, when the first demodulation control signal V CS1 To the fourth demodulation control signal V CS4 Each of them has a second voltage (V 2 ), electrons generated by each of the first to fourth sub-pixels SP1 to SP4 may be captured by the detection area 130.

[0171] After the captured electrons move through the transfer transistor TX, the electrons accumulated in the floating diffusion region (FD) may be output as a pixel signal after passing through the drive transistor DX and the select transistor SX.

[0172] After the pixel signal is output, the first to fourth sub-pixels SP1 to SP4 can be reset to a predetermined voltage (eg, pixel voltage V px ).

[0173] Each of the sub-pixels SP1 to SP4 may include a reset transistor RX and a transfer transistor TX, so that a reset signal RST and a transfer signal TRG may be applied to each of the sub-pixels SP1 to SP4. The reset signal RST and the transfer signal TRG may be applied to each of the sub-pixels SP1 to SP4 by means of a row driver 41.

[0174] When the pixel signal of the unit pixel (PX) is detected, the first voltage (V 1 ) can be applied to the voltage application region 150. As described above, since the first voltage (V 1 ) is applied to the voltage applying region 150, the electrons can be easily detected by the detection region 130, and noise caused by the movement of electrons flowing between adjacent sub-pixels (eg, SP1 and SP3) can be reduced.

[0175] Modulated light (ML) may refer to light emitted by the light source 10 controlled by the control block 40 toward the target object 1. The modulated light (ML) may be generated to alternately have a high level section (i.e., a period of emitting light) and a low level section (i.e., a period of not emitting light).

[0176] The incident light (IL) may refer to light that is incident on the substrate to generate electron-hole pairs by a photoelectric conversion effect. The incident light (IL) may have a phase difference (θ) that changes with the distance between the image sensing device ISD and the target object 1.

[0177] Figure 5 The level of each of the modulated light (ML) and the incident light (IL) shown in may refer to the intensity of the light. For example, "H" may refer to high-intensity light, and "L" may refer to low-intensity light.

[0178] When electrons generated by the incident light (IL) are captured in the detection area 130 included in each of the sub-pixels SP1 to SP4, the first demodulation control signal (V CS1 ), the second demodulation control signal (V CS2 ), the third demodulation control signal (V CS3 ) and the fourth demodulation control signal (V CS4 ) can alternately apply a second voltage (V 2 ) and the third voltage (V 3 ).

[0179] is used to demodulate the second voltage (V 2 ) applied to the demodulation driver 42 of the control area 140 can be regarded as a logic high level (H). In addition, the third voltage (V 3 ) applied to the demodulation driver 42 of the control area 140 can be regarded as a logic low level (L). For example, the second voltage (V 2 ) may be 1.2V, and the third voltage (V 3 ) can be zero volts (0V).

[0180] In addition, the first demodulation control signal (V CS1 ) can have the same phase as the modulated light (ML), and the second demodulation control signal (V CS2 ) may have a phase difference of 180° (π) relative to the modulated light (ML), and the third demodulation control signal (V CS3 ) may have a phase difference of 90° (π / 2) relative to the modulated light (ML), and the fourth demodulation control signal (V CS4 ) can have a phase difference of 270° (3π / 2) relative to the modulated light (ML).

[0181] In some implementations, for ease of description, it is assumed that no phase difference occurs between the optical modulation signal MLS generating the modulated light (ML) and the modulated light (ML), so that the optical modulation signal MLS and the modulated light (ML) may have the same phase.

[0182] The second voltage (V 2 ) and the third voltage (V 3 ) With the help of the first demodulation control signal V CS1 To the fourth demodulation control signal V CS4 The control area 140 included in each of the sub-pixels SP1 to SP4 is periodically applied, so that the sensing operation of the sub-pixels SP1 to SP4 will be described below focusing on the first period PR1 to the twelfth period PR12.

[0183] The first demodulation control signal (V CS1 ) may have a second voltage (V 2 ), and may have a third voltage (V 3 ).

[0184] The second demodulation control signal (V CS2 ) may have a second voltage (V 2 ), and may have a third voltage (V 3 ).

[0185] The third demodulation control signal (V CS3 ) may have a second voltage (V 2 ), and may have a third voltage (V 3 ).

[0186] The fourth demodulation control signal (V CS4 ) may have a second voltage (V 2 ), and may have a third voltage (V 3 ).

[0187] The first demodulation control signal V is respectively applied to the sub-pixels SP1 to SP4 included in one unit pixel (PX). CS1 To the fourth demodulation control signal VCS4 The second voltage (V 2 ). Therefore, the second voltage (V 2 ) can be simultaneously applied to two arbitrary sub-pixels (e.g., SP1 and SP3) included in one unit pixel (PX).

[0188] For example, the first demodulation control signal (V CS1 ) and a third demodulation control signal (V CS3 ) can have the second voltage (V 2 Therefore, during the third period PR3 and the ninth period PR9, the second voltage (V 2 ) may be applied to the control regions 140 respectively included in the first and third sub-pixels SP1 and SP3.

[0189] The first isolation portion 110 included in the unit pixel (PX) may control the movement of electrons flowing between adjacent sub-pixels (eg, SP1 and SP2), so that the demodulation driver 42 may simultaneously apply the second voltage (V 2 ) to capture electrons.

[0190] For the second voltage (V 2 ) The demodulation control signals applied to the control area 140 respectively included in the adjacent sub-pixels SP1 to SP4 are simultaneously applied to the control area 140, so that the time for detecting electrons from each of the sub-pixels SP1 to SP4 can be reduced.

[0191] The incident light (IL) having a phase difference (θ) with respect to the modulated light (ML) may be incident on the substrate. For example, the incident light (IL) may have a high intensity (H) indicating a high level in the second period PR2, the third period PR3, the fourth period PR4, the eighth period PR8, the ninth period PR9, and the tenth period PR10.

[0192] Each of the first to fourth sub-pixels SP1 to SP4 may be controlled by a demodulation control signal V applied to the first to fourth sub-pixels SP1 to SP4, respectively. CS1 To V CS4 Electrons generated by incident light (IL) are captured in the period having a logic high level (H).

[0193] The first sub-pixel SP1 may capture electrons generated by the incident light (IL) in the second period PR2 , the third period PR3 , the eighth period PR8 , and the ninth period PR9 .

[0194] The first demodulation control signal (V cs1 ) can be a second voltage (V 2 ) and the third voltage (V 3 ) is configured in a periodically repeated manner so that the amount of electrons captured by the first subpixel SP1 in the second period PR2 and the third period PR3 can be the same as the amount of electrons captured by the first subpixel SP1 in the eighth period PR8 and the ninth period PR9. In this case, the electrons captured by the first subpixel SP1 in the second period PR2 and the third period PR3 can be defined as Q(0).

[0195] The second sub-pixel SP2 may capture electrons generated by the incident light (IL) in the fourth period PR4 and the tenth period PR10.

[0196] The second demodulation control signal (V CS2 ) can be a second voltage (V 2 ) and the third voltage (V 3 ) is configured in a periodically repeated manner so that the amount of electrons captured by the second sub-pixel SP2 in the fourth period PR4 can be the same as the amount of electrons captured by the second sub-pixel SP2 in the tenth period PR10. In this case, the electrons captured by the second sub-pixel SP2 in the fourth period PR4 can be defined as Q(π).

[0197] The third subpixel SP3 may capture electrons generated by the incident light (IL) in the third period PR3 , the fourth period PR4 , the ninth period PR9 , and the tenth period PR10 .

[0198] The third demodulation control signal (V CS3 ) may be configured in a manner that the second voltage (V2) and the third voltage (V3) are periodically repeated, so that the amount of electrons captured by the third sub-pixel SP3 in the third period PR3 and the fourth period PR4 may be the same as the amount of electrons captured by the third sub-pixel SP3 in the ninth period PR9 and the tenth period PR10. In this case, the electrons captured by the third sub-pixel SP3 in each of the third period PR3 and the fourth period PR4 may be defined as Q(π / 2).

[0199] The fourth sub-pixel SP4 may capture electrons generated by the incident light (IL) in the eighth period PR8.

[0200] In this case, electrons captured by the fourth subpixel SP4 in the eighth period PR8 may be defined as Q(3π / 2).

[0201] The image sensing device ISD may perform a sensing operation and distance information detection in units of four adjacent unit pixels (eg, SP1 , SP2 , SP3 , and SP4 ) included in one unit pixel (PX).

[0202] Each unit pixel (PX) arranged in the pixel array 30 may include first to fourth sub-pixels SP1, SP2, SP3, and SP4. Each of the first to fourth sub-pixels SP1 to SP4 may receive a first demodulation control signal V CS1 To the fourth demodulation control signal V CS4 That is, the sub-pixels SP1 to SP4 arranged in the pixel array 30 can receive the demodulation control signal V CS1 To V CS4 .

[0203] Each of the sub-pixels SP1, SP2, SP3, and SP4 may output a pixel signal corresponding to electrons applied to the floating diffusion area FD. An image processor (not shown) may acquire a distance from the image sensing device ISD to the target object 1 by processing the output pixel signal.

[0204] The image sensing device ISD may calculate a phase difference (θ) using the detected electrons Q(0), Q(π / 2), Q(π), and Q(3π / 2).

[0205] Electrons generated by incident light (IL) applied to the pixel array 30 may be captured by four adjacent sub-pixels SP1 , SP2 , SP3 , and SP4 in different partitioned manners according to corresponding phases.

[0206] The first demodulation control signal (V CS1 ), a second demodulation control signal (V CS2 ), a third demodulation control signal (V CS3 ) and a fourth demodulation control signal (V CS4 ) may each have a phase difference of π / 2 (rad). An image processor (not shown) may receive image data corresponding to Q(0), image data corresponding to Q(π), image data corresponding to Q(π / 2), and image data corresponding to Q(3π / 2) from four adjacent sub-pixels SP1, SP2, SP3, and SP4, respectively.

[0207] The image processor (not shown) may calculate a phase difference based on the image data, and may acquire a distance from the image sensing device ISD to the target object 1 .

[0208] Figure 61 is a conceptual diagram showing an embodiment of a voltage to be applied to a unit pixel (PX) during an operation time of the unit pixel (PX) and a distribution of a potential generated in the operating unit pixel (PX) based on some implementations of the disclosed technology.

[0209] As from Figure 6 It can be seen that when the unit pixel (PX) operates in the seventh period PR7 and the eighth period PR8, Figure 6 2 and 3 show voltages applied to the first and third sub-pixels SP1 and SP3.

[0210] although Figure 6 For the convenience of description, the operation time points of the seventh period PR7 and the eighth period PR8 are exemplarily shown, but during the operation time of the fourth period PR4 and the fifth period PR5, the potential distributions of two arbitrary sub-pixels (for example, SP2 and SP4) included in the unit pixel (PX) may also be different from those of the first period PR7 and the eighth period PR8. Figure 6 At this time, the area of ​​the second sub-pixel SP2 may correspond to Figure 6 The area of ​​the first sub-pixel SP1 shown in FIG. 1 and the area of ​​the fourth sub-pixel SP4 may correspond to Figure 6 The area of ​​the third sub-pixel SP3 is shown in FIG.

[0211] In addition, the first demodulation control signals V applied to the sub-pixels SP1 to SP4 are respectively CS1 To the fourth demodulation control signal V CS4 It may be repeated at predetermined time intervals so that the above potential distribution may also be similarly applied to other operation time points.

[0212] For example, for the first period PR1 and the second period PR2, the voltage applied to the first sub-pixel SP1 and the third sub-pixel SP3 may be Figure 6 Those voltages are essentially the same.

[0213] refer to Figure 6 During the seventh period PR7 and the eighth period PR8, the second voltage (V 2 ) (eg, 1.2 V) may be applied to the control region 140 included in the first sub-pixel SP1, and a third voltage (V 3 ) (eg, 0 V) ​​may be applied to the control region 140 included in the second sub-pixel SP2.

[0214] In addition, a first voltage (eg, -0.2 V to -0.5 V) may be applied to the voltage applying region 150, and a ground voltage (V GND ) (eg, 0 V) ​​may be applied to the second isolation portion 120 .

[0215] in this case, Figure 6, a portion of the current flowing between the voltage applying region 150 and the control region 140 is shown. In addition, the current may also flow between the control region 140 and the second isolation portion 120 included in the first sub-pixel SP1.

[0216] This flow of current may be opposite in direction to the movement of electrons. When current flows from the control region 140 included in the first subpixel SP1 to the voltage applying region 150, the electrons may move from the voltage applying region 150 to the control region included in the first subpixel SP1.

[0217] During the operation time of the unit pixel (PX), the detection voltage (V DR ) may be applied to the detection zone 130. In this case, the detection zone 130 may capture electrons moving along the current.

[0218] When a negative (-) voltage is applied to the voltage application region 150, the voltage application region 150 is connected to the voltage application region 150 to which the third voltage (V 3 ) may cause a potential difference between the control regions 140. The current can be received from the third voltage (V 3 ) flows to the control region 140 receiving a negative (-) voltage (eg, the first voltage V 1 ) of the voltage application area 150. Figure 6 , current may flow between the control area 140 and the voltage applying area 150 included in the third sub-pixel SP3.

[0219] Since the third voltage (V 3 ) generates a potential difference between the control area 140 and the voltage application area 150, so that the third voltage (V 3 ) moves to a sub-pixel (eg, SP3) that receives a second voltage (V 2 ) may decrease. At this time, the electrons whose movement is limited may be the electrons generated in the previous detection operation time (for example, the electrons generated in the third sub-pixel SP3 in the third period PR3 to the fifth period PR5).

[0220] If there is no potential difference between the voltage applied to the voltage application area 150 and the voltage applied to the control area 140, the third voltage (V 3 ) of the sub-pixel (e.g. Figure 6 The electrons generated by SP3 but not captured in the detection operation may easily move toward the receiving second voltage (V 2 ) of the sub-pixel (e.g. Figure 6 SP1) Mobile.

[0221] When the negative (-) voltage (V 1 ) is applied to the voltage application region 150, the first voltage (V1 ) is lower than the third voltage (V 3 ), so that the current can flow between the voltage application region 150 and the receiving third voltage (V 3 ) flows between the control regions 140. As a result, the Figure 6 Electrons generated in the SP3 of FIG. 1 but not captured in the detection operation may not easily flow to adjacent sub-pixels (eg Figure 6 SP1) Mobile.

[0222] Figure 6 The potential energy distribution corresponding to the cross section of the unit pixel (PX) is shown.

[0223] Electrons can move from a low voltage region to a high voltage region. As the voltage of the region becomes lower, it means that the potential energy of the electrons generated in the region becomes higher.

[0224] As from Figure 5 It can be seen that during the operation time of the unit pixel (PX), the first voltage (V 1 ) can be applied to the voltage application area 150.

[0225] Since the first voltage (V 1 ) is lower than the second voltage (V 2 ), the third voltage (V 3 ) and the detection voltage (V DR ) of each of which has a low voltage (e.g., -0.2V to -0.5V), so a first voltage (V 1 ) can have the highest potential.

[0226] exist Figure 5 In the first period PR1 and the second period PR2 shown in FIG. 2 ) may be applied to the control region 140 of the first sub-pixel SP1. The second voltage (V 2 ) is higher than the third voltage (V 3 ) and is lower than the first voltage (V 1 ), so that the electrons generated in the first sub-pixel SP1 can move toward the applied second voltage (V 2 ) area moves.

[0227] The third voltage (V 3 ) may be applied to the control area 140 of the third sub-pixel SP3. 3 ) is higher than the first voltage (V 1 ), so the electrons generated in the third sub-pixel SP3 may not easily cross the voltage application area 150. Therefore, the first voltage (V 1) The movement of electrons generated in adjacent sub-pixels causes noise.

[0228] Detection voltage (V DR ) may be applied to the detection region 130 included in the unit pixel (PX). For example, the detection voltage (V DR ) may be set to 2.8 V. Electrons generated in the sub-pixels (eg, SP1 to SP4) may move toward the detection region 130 corresponding to the lowest potential region.

[0229] Subpixels (eg, SP1 to SP4) included in each unit pixel (PX) may be isolated from adjacent unit pixels (PX) by second isolation portions 120. Second isolation portions 120 may physically and electrically isolate photoelectric conversion regions 160 respectively included in unit pixels (PX) from each other.

[0230] Since the second isolation portion 120 is formed to have the same depth as the formation depth of the photoelectric conversion region 160 , movement of electrons flowing between adjacent unit pixels (PX) may be prevented.

[0231] In addition, when the ground voltage (V GND ) is applied to the second isolation portion 120 and is lower than the detection voltage (V DR ), the electrons can be prevented from moving toward the adjacent unit pixel (PX) by means of the second isolation portion 120.

[0232] Figure 7 and Figure 8 is a diagram showing an embodiment of a method for forming a first isolation portion and a second isolation portion based on some implementations of the disclosed technology.

[0233] refer to Figure 7 The first isolation portion 110 may include a first doping region 112 , a second doping region 114 , and a third doping region 116 . The second isolation portion 120 may include a fourth doping region 122 , a fifth doping region 124 , and a sixth doping region 126 .

[0234] The third doping region 116 may have a lower density than the first doping region 112 and may be formed by ion implantation. The sixth doping region 126 may have a lower density than the fourth doping region 122 and may be formed by ion implantation. In this case, the conductivity type of the implanted ions may be P-type, and P-type ions may be used for such ion implantation.

[0235] exist Figure 7 In the embodiment of the present invention, the depth of the isolation portions 110 and 120 formed by the ion implantation process may be limited by the ion implantation depth limitation.

[0236] exist Figure 7 In an embodiment, when the third doping region 116 is formed to have the same direction as the first doping region 112 and the second doping region 114 when viewed from the substrate, the formation depth of the first isolation portion 110 may be limited. Similarly, when the sixth doping region 126 is formed to have the same direction as the fourth doping region 122 and the fifth doping region 124 when viewed from the substrate, the formation depth of the second isolation portion 120 may be limited. In some implementations, "formed to have the same direction" may refer to doping impurities in the same direction from the front side of the substrate or the back side of the substrate.

[0237] Therefore, when the doped regions included in the first isolation portion 110 and the second isolation portion 120 are formed after being doped in the same direction relative to the substrate, the thickness of the substrate or the epitaxial layer in which the first isolation portion 110 and the second isolation portion 120 are doped may be limited.

[0238] refer to Figure 8 The first isolation portion 110 may include a first doping region 112 , a second doping region 114 , and a third doping region 116 . The second isolation portion 120 may include a fourth doping region 122 , a fifth doping region 124 , and a sixth doping region 126 .

[0239] and Figure 7 The implementation methods are different. Figure 8 The embodiment of the present invention shows that the third doping region 116 is doped in the opposite direction of the first doping region 112 and the second doping region 114 relative to the substrate. Similarly, the sixth doping region 126 is doped in the opposite direction of the fourth doping region 122 and the fifth doping region 124 relative to the substrate. For example, the first doping region 112, the second doping region 114, the fourth doping region 122 and the fifth doping region 124 can be doped from the front side of the substrate, and the third doping region 116 and the sixth doping region 126 can be doped from the back side of the semiconductor substrate or the epitaxial layer. The doping method of the third doping region 116 and the sixth doping region 126 described above can be called a back implantation process.

[0240] The third doping region 116 may have a lower density than the first doping region 112 and may be formed by an ion implantation process. Similarly, the sixth doping region 126 may have a lower density than the fourth doping region 122 and may be formed by an ion implantation process. The conductivity type of the implanted ions may be P-type, so that P-type ions may be used for such ion implantation.

[0241] When the third doping region 116 is doped in the opposite direction to the first doping region 112 and the second doping region 114 , the first isolation portion 110 may be formed on the entirety of the semiconductor substrate or the epitaxial layer without limiting the thickness of the epitaxial layer or the semiconductor substrate.

[0242] Similarly, when the sixth doping region 126 is doped in the opposite direction to the fourth doping region 122 and the fifth doping region 124 , the second isolation portion 120 can be formed on the entirety of the semiconductor substrate or epitaxial layer without limiting the thickness of the epitaxial layer or the semiconductor substrate.

[0243] exist Figure 8 In the embodiment of the present invention, the third doping region 116 and the sixth doping region 126 may be formed after the first doping region 112 , the second doping region 114 , the fourth doping region 122 , and the fifth doping region 124 are formed.

[0244] In addition, in such a manner that the isolation portions 110 and 120 can be formed simultaneously with the formation of the first doping region 112, the second doping region 114, the fourth doping region 122 and the fifth doping region 124, the doping positions of the impurities forming the third doping region 116 and the sixth doping region 126 can be determined using a photoresist (PR) mask.

[0245] Fig. 9 FIG. 4 is a schematic diagram showing an embodiment of a unit pixel 900 having multiple detection areas 930 based on some other implementations of the disclosed technology.

[0246] refer to Fig. 9 , each detection region 930 may be formed around each control region 940 , and may be formed to open a gap (spacing) between the voltage application region 950 and each control region 940 .

[0247] When each detection region 930 is formed to be opened between the voltage application region 950 and each control region 940, the current flowing between the voltage application region 950 and each control region 940 may not be affected by the detection voltage (V DR )’s impact.

[0248] In addition, the control region 940 and the detection region 930 included in each of the sub-pixels SP1 to SP4 may be formed adjacent to the second isolation portion 920 for the corresponding sub-pixels SP1 to SP4 .

[0249] If the control region 940 and the detection region 930 are formed adjacent to the second isolation portion 920, the voltage applying region 950 and the detection region 930 are located adjacent to the second isolation portion 920, compared to other cases where the control region 940 and the detection region 930 are formed at the center of each sub-pixel SP1 to SP4. 2 ) can increase the length of the current path flowing between each control area.

[0250] If the voltage application area 950 receives the second voltage (V 2) increases, the electrons generated by the corresponding sub-pixels SP1 to SP4 can easily move along the flow of current.

[0251] Since the control region 940 and the detection region 930 are formed adjacent to the second isolation portion 920 , electrons generated between the voltage applying region 950 and each control region 940 can be easily captured by means of the detection region 930 .

[0252] It is apparent from the above description that an image sensing device based on some implementations of the disclosed technology may allow a control region included in a unit pixel to be surrounded by an isolation portion, thereby improving electronic detection efficiency and reducing signal interference between adjacent sub-pixels.

[0253] Furthermore, due to the voltage applying region located at the center of each unit pixel, signal interference between adjacent sub-pixels can be reduced, and electron transfer efficiency can be improved.

[0254] The embodiments of the disclosed technology can provide various effects that can be directly or indirectly recognized through the above disclosure.

[0255] Those skilled in the art will appreciate that the disclosed technology may be implemented in other specific ways than those set forth herein.

[0256] Although some exemplary embodiments have been described, it should be understood that variations of the disclosed embodiments and other embodiments may be devised based on what is described and / or illustrated in this disclosure.

[0257] CROSS-REFERENCE TO RELATED APPLICATIONS

[0258] The present disclosure claims priority to and the benefit of Korean Patent Application No. 10-2021-0015576, filed on February 3, 2021, the disclosure of which is incorporated by reference in its entirety as a part of the present disclosure.

Claims

1. An image sensing device, the image sensing device include: Multiple unit pixels, Each of the unit pixels generates a photocharge indicating the detected incident light in response to the incident light, and includes: sub-pixels, each sub-pixel comprising a control region, the control region generating a current carrying the photocharge in a substrate on which the sub-pixel is arranged; and a detection region, the detection region being separated from the control region and capturing the photocharges carried by the current; a plurality of first isolation portions, wherein the first isolation portions are arranged between two adjacent sub-pixels; a second isolation portion, the second isolation portion being arranged to surround the sub-pixel; and A voltage applying region is arranged at a central portion of the unit pixel and receives a first voltage.

2. The image sensing device according to claim 1, in, Each of the first isolation portion and the second isolation portion receives a ground voltage higher than the first voltage.

3. The image sensing device according to claim 1, in, Each of the plurality of first isolation portions comprises: a first doped region having a first depth; a second doped region having a second depth; and A third doping region is formed to have a third depth, The sum of the first depth, the second depth and the third depth is the same as the depth of the substrate.

4. The image sensing device according to claim 3, in, The first doping region and the second doping region have different doping densities from each other.

5. The image sensing device according to claim 1, in, The second isolation portion comprises: a fourth doped region having a fourth depth; a fifth doped region having a fifth depth; and a sixth doped region having a sixth depth, The sum of the fourth depth, the fifth depth and the sixth depth is the same as the depth of the substrate.

6. The image sensing device according to claim 5, in, The fourth doping region and the fifth doping region have different doping densities from each other.

7. The image sensing device according to claim 1, in, The control section receives a demodulation control signal, the demodulation control signal having a second voltage in a first period and having a third voltage in a second period.

8. The image sensing device according to claim 7, in, Each of the second voltage and the third voltage is higher than the first voltage.

9. The image sensing device according to claim 8, in, The sub-pixels include first to fourth sub-pixels to which different demodulation control signals are applied.

10. The image sensing device according to claim 9, in, The first to fourth demodulation control signals are applied to the first to fourth sub-pixels, respectively, and Wherein, the first demodulation control signal has a phase difference of 90° with respect to the second demodulation control signal; The second demodulation control signal has a phase difference of 90° relative to the third demodulation control signal; The third demodulation control signal has a phase difference of 90° with respect to the fourth demodulation control signal; and The fourth demodulation control signal has a phase difference of 90° with respect to the first demodulation control signal.

11. The image sensing device according to claim 1, in, The detection zone is arranged between the control zone and the second isolation portion.

12. The image sensing device according to claim 11, in, The detection zone is arranged to surround the control zone, Wherein, an opening is arranged between the control area and the voltage application area.

13. The image sensing device according to claim 1, in, A current flows from each of the control region, the first isolation portion, and the second isolation portion to the voltage applying region.

14. The image sensing device according to claim 1, in, The voltage applying region is spaced apart from each of the first isolation portions.

15. An image sensing device, the image sensing device include: sub-pixels arranged in a matrix array, each sub-pixel including a photoelectric conversion region that generates photocharges in response to incident light; a first isolation portion, the first isolation portion being arranged to isolate any two adjacent sub-pixels from each other; a second isolation portion, the second isolation portion being arranged along an edge of the sub-pixel; as well as A voltage applying region is arranged at a central portion of the matrix array and receives a first voltage which is a negative voltage.

16. The image sensing device according to claim 15, in, Each of the sub-pixels further comprises: a detection region that captures the photocharges moving along the current; and A control region that allows the current to flow to the first isolation portion, the second isolation portion, and the voltage application region.

17. The image sensing device according to claim 16, in, The control region further generates a hole current by receiving a control signal having a second voltage or a third voltage.

18. The image sensing device according to claim 16, in, The voltage applying region is arranged to be spaced apart from the first isolation portion and the second isolation portion.

19. The image sensing device according to claim 16, in, The first isolation portion and the second isolation portion are coupled to each other.

20. The image sensing device according to claim 16, in, A voltage applied to the first isolation portion and the second isolation portion is different from the first voltage.

Images