TOF sensor having pixel structure including shared area

Abstract

A time of flight (TOF) sensor having a pixel structure including a shared area is disclosed. The TOF sensor according to at least one of various embodiments of the present disclosure has a pixel structure including a plurality of pixels for sensing a phase difference in a received image signal. A specific area is formed between a first pixel and a second pixel from among the plurality of pixels, and the specific area can be an area shared by the first pixel and the second pixel.

Description

TOF sensor with pixel structure including shared area

[0001] The present disclosure relates to a Time of Flight (ToF) sensor having a pixel structure including a shared area.

[0002] ToF (Time of Flight) sensor is a technology used to measure the distance between objects.

[0003] These ToF sensors can calculate the distance to an object by measuring the time it takes for light to reflect from the object and return using optical methods.

[0004] In the past, when sensing the phase difference in the image signal received by the ToF sensor, the sensitivity was reduced due to noise, and methods designed for noise removal, etc. had the problem of difficulty in high-speed operation.

[0005] Accordingly, there is a need for a pixel structure that can operate at high speed while removing noise and increasing sensitivity.

[0006] The present disclosure aims to provide a ToF (Time of Flight) sensor and an operating method thereof that minimizes noise of the ToF sensor while improving pixel sensitivity.

[0007] Another object of the present disclosure is to provide a ToF sensor having a pixel structure having an overlapping and / or phase swap function between a plurality of pixels in a row and / or column unit, and an operating method thereof.

[0008] The technical problems of the present disclosure are not limited to those described in this article, but include those that can be understood through the description of the invention.

[0009] A Time of Flight (ToF) sensor according to at least one of the various embodiments of the present disclosure may be formed with a pixel structure including a plurality of pixels that sense a phase difference in a received image signal, wherein a specific region is formed between a first pixel and a second pixel among the plurality of pixels, and the specific region may be a region shared by the first pixel and the second pixel.

[0010] In a ToF sensor according to at least one of the various embodiments of the present disclosure, at least one photodiode and a photogate for each of the first pixel and the second pixel may be formed in the shared area.

[0011] In a ToF sensor according to at least one of the various embodiments of the present disclosure, each photogate formed in the shared area may extend to photogates formed in each of the first pixel and the second pixel.

[0012] In a ToF sensor according to at least one of the various embodiments of the present disclosure, the pixel structure may be configured such that a phase difference between the first pixel and the second pixel can be inverted in a row unit through the shared area.

[0013] In a ToF sensor according to at least one of the various embodiments of the present disclosure, the pixel structure may be such that a phase difference between the first pixel and the second pixel can be reversed in a column unit through the shared area.

[0014] In a ToF sensor according to at least one of the various embodiments of the present disclosure, the extension is performed using a junction diode under a storage gate, and the pixel structure may not have N+ formed in the active area around the photodiode.

[0015] In a ToF sensor according to at least one of the various embodiments of the present disclosure, the photogate formed in the shared area may be connected to the photogates of the first pixel and the second pixel by metal.

[0016] In a ToF sensor according to at least one of the various embodiments of the present disclosure, in the pixel structure, a 4-tap structure is provided between the first pixel, the shared area, and the second pixel, with the first tap and the second tap being arranged alternately and sequentially, and each tap can be connected to an output terminal of a different pixel in a column unit.

[0017] In a ToF sensor according to at least one of the various embodiments of the present disclosure, the shared area may be one of a pixel or a non-pixel.

[0018] In a ToF sensor according to at least one of the various embodiments of the present disclosure, the pixel structure may not be physically separated between adjacent pixels according to a Shallow Trench Isolation (STI) process.

[0019] According to at least one of the various embodiments of the present disclosure, the following effects are achieved.

[0020] First, it has the advantage of being able to improve pixel sensitivity.

[0021] Second, it has the advantage of minimizing sensor noise.

[0022] Third, there is an advantage in being able to propose a pixel structure with page swap functionality.

[0023] The technical effects of the embodiments are not limited to those described in this article, but include those that can be understood through the description of the invention.

[0024] Figure 1 is a diagram illustrating the transmission, reflection, and reception principles in a ToF system.

[0025] Figure 2 is a drawing illustrating the distance, phase distance, and FPPN of the target plane.

[0026] FIG. 3 is a drawing illustrating a ToF pixel structure according to an embodiment of the present disclosure.

[0027] FIG. 4 is a drawing illustrating a ToF pixel structure according to another embodiment of the present disclosure.

[0028] FIGS. 5 and 6 are drawings illustrating a circuit diagram type according to one embodiment of the present disclosure.

[0029] FIGS. 7 to 10 are drawings illustrating a physical pixel structure according to an embodiment of the present disclosure.

[0030] FIG. 11 is a schematic diagram illustrating signal processing in a ToF pixel according to an embodiment of the present disclosure.

[0031] Hereinafter, an invention according to an embodiment for solving the above problem will be described in more detail with reference to the drawings.

[0032] The suffixes "module" and "part" used in the following description are given solely for the convenience of writing this specification and do not impart any particularly significant meaning or role to the components themselves. Therefore, the terms "module" and "part" may be used interchangeably.

[0033] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0034] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0035] In this application, it should be understood that terms such as “include,” “have,” or “comprising” are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0036] This specification discloses a pixel structure of a sensor according to at least one of various embodiments of the present disclosure. Here, the sensor may include, for example, a Time of Flight (ToF) sensor or a ToF-based image sensor.

[0037] In the following specification, for convenience of explanation, a ToF sensor is used as an example, and the pixel structure of the ToF sensor is disclosed.

[0038] Fig. 1 (a) is illustrated to explain the principles of emission, reflection, and reception in a ToF system (or ToF sensor) in relation to the present disclosure, and Fig. 1 (b) is illustrated to explain four phase step samples.

[0039] As illustrated in (a) of Fig. 1, the ToF system may include an optical transmitter (Tx) and an optical receiver (Rx).

[0040] Here, an optical transmitter (Tx) can transmit a modulated signal that is reflected by an object, while an optical receiver (Rx) can detect the reflected signal.

[0041] At this time, the distance to the target can be measured based on the round-trip time of light from the optical transmitter (Tx) to the optical receiver (Rx). Meanwhile, if the signal is periodic, the phase change between the transmitted signal and the signal reflected from the object and received can be used as an indicator of the round-trip time.

[0042] Figure 1 illustrates the process by which an optical signal travels back and forth through the environment to a target. The distance can be calculated as in Equation 1 based on the time delay Δt and the speed of light c.

[0043]

[0044] An integrated system utilizing the TOF principle can measure distance using either pulse mode control or continuous wave (CW) mode control.

[0045] The continuous wave (CW) mode control method can estimate the phase between the two signals by using the cross-correlation operation between the transmitting and receiving signals.

[0046] As one method of phase measurement, four samples of the transmitted signal, each 90° in phase, can be considered. Electrical accumulation from the reflected signal during the four samples is performed, and the amount of photons can be detected at Q1, Q2, Q3, and Q4, as illustrated in (b) of Fig. 1.

[0047]

[0048] Looking more closely at the continuous wave (CW) phase φ, the difference between (Q3- Q4) and (Q1- Q2) can normalize the constant offset of the returned signal. The offset can occur when ambient light interferes with the transmitted signal. Additionally, the ratio between (Q3- Q4) and (Q1- Q2) can provide amplitude normalization. In reality, the amount of energy received is reduced compared to the transmitted energy due to dispersion, which results in a reduced amplitude. Independence of signal offset and attenuation is necessary for robust phase estimation. The amplitude (A) and offset (B) of the returned signal can be estimated according to Equation 3.

[0049]

[0050]

[0051] The amplitude A and offset B of the reflected signal affect the depth measurement accuracy σ. The measurement variance can be approximated by Equation 4, where the modulation contrast ratio c d This indicates how well the ToF sensor separates and collects photoelectrons. Higher amplitude, higher modulation frequency (up to physical limits), and higher modulation contrast can actually improve accuracy. Large offsets can lead to saturation and inaccuracy.

[0052]

[0053] A pixel structure of a ToF sensor according to an embodiment of the present disclosure is disclosed.

[0054] There are methods such as making the phase between rows different (0-180 row, 90-270 row), making the phase different for each pixel, and inverting the phase of the gate switch. This is because four phases (0-180, 90-270) are required to extract the distance in ToF, and since FPN (Fixed Phase Noise) occurs due to the offset effect between each switch, the phase must be inverted again to read out. In order to improve this, two phases are arranged for each pixel and the phase inversion between switches (e.g., 0-180 -> 180-0) is performed, and these are synthesized during subsequent data processing.

[0055] However, this method drives the photogates with a 90-degree phase difference per row, and adjacent pixels must be arranged so that their phases are inverted by 180 degrees. For example, in a 2-tap (e.g., photogate A, B) / pixel structure, when implementing a 4-tap structure, the phases are inverted to reduce the FPN caused by the mismatch of the left and right elements of the pixels.

[0056] However, this method has the disadvantage that mismatches between the output within the pixel, i.e. column to column, are output (V 0,90 and V 180,270 ) has a fixed location, making it difficult to solve.

[0057] To solve this, the metal routing is crossed once to invert the phase between adjacent pixels, which breaks the routing symmetry and causes FPN.

[0058] Accordingly, in the present disclosure, a pixel structure having a phase swap function between columns is disclosed so that the sensitivity of pixels can be improved by overlapping adjacent pixels while minimizing the fixed phase pattern noise (FPPN) of the ToF sensor, as low-noise pixel readout is required for sensing a phase difference in an image signal received by a ToF sensor using a modulated light source, and high sensitivity, high-speed operation, etc. are required.

[0059] Figure 2 is a drawing illustrating the distance, phase distance, and FPPN of the target plane.

[0060] FPPN, which corresponds to FPN within the depth frame, is a defect caused by a mismatch between pixels and readout.

[0061] Referring to (a) of FIG. 2, a ToF pixel may have two switches in one photodiode, each storing a photodiode signal with a phase difference of 180 degrees, and may have two output lines for each pixel.

[0062] The offset and column-to-column mismatch characteristics between transistors that constitute a switch can be expressed as the FPN of the phase signal, as shown in (c) of Fig. 2. In (c) of Fig. 2, the uppermost graph represents the target plane distance, the middle graph represents the distance, and the lowermost graph represents the FPPN.

[0063] Therefore, in this case, to minimize FPPN, it is necessary to use two frame data as shown in (b) of Fig. 2, i.e., to additionally read out a frame that reverses the phase difference between taps A and B (0-180, 180-0). Therefore, referring to Equation 5 of the frame rate due to reading out an additional frame, the speed inevitably decreases by half.

[0064]

[0065]

[0066]

[0067] FIG. 3 is a drawing illustrating a ToF pixel structure according to an embodiment of the present disclosure.

[0068] FIG. 3 illustrates an example of a pixel structure to which an adjacent pixel overlapping method according to an embodiment of the present disclosure is applied.

[0069] In the case of the pixel structure described above, the phase difference between adjacent rows must be inverted, but to invert the phase difference between adjacent rows like this, the metal routing must be crossed.

[0070] On the other hand, in a pixel structure according to an embodiment of the present disclosure, a method of overlapping adjacent pixels is proposed. This is a method of simultaneously reading out the left and right signals of a photogate switch (PG) according to the overlapping of adjacent pixels. In other words, the phase difference between rows can be inverted so that the mismatch phenomenon between columns in the readout is eliminated. When depth is calculated in a ToF sensor according to this method, the offset between transistors (TR) can be eliminated.

[0071] The pixel structure can be, for example, a 2x2 array as a basic unit. Therefore, typically, one pixel may include one storage diode (SD) and two photodiodes (PD). Additionally, each pixel may have one tap, to which a photogate (PG) switch may be connected. However, this is not a limitation.

[0072] In Fig. 3, a two-tap structure is disclosed.

[0073] In the pixel structure according to the present disclosure, an overlapping area (350) (hereinafter referred to as a “shared area”) exists between the first pixel (310) and the second pixel (320). However, the present disclosure is not limited to this term.

[0074] Meanwhile, in the present disclosure, such shared area may be a pixel or may not be a pixel (e.g., non-pixel).

[0075] In FIG. 3, a photodiode (PD) exists in the shared area (350). Therefore, the photodiode (PD) included in the shared area (330) can be involved in both the first pixel (310) and the second pixel (320).

[0076] Meanwhile, referring to FIG. 3, two tabs (tab A and tab B) are configured based on the shared area (350).

[0077] In FIG. 3, the phases of the first pixel (310) and the second pixel (320) and the phases of the third pixel (330) and the fourth pixel (340) can be inverted in row units. That is, data with a phase of 0 degrees can be acquired in tap A, and data with a phase of 180 degrees can be acquired in tap B.

[0078] On the other hand, the phases of the first pixel (310) and the third pixel (330) and the phases of the second pixel (320) and the fourth pixel (340) in the column unit may be the same. That is, only data with a phase of 0 degrees can be acquired through the photogate (PG_A) switch of tab A, and only data with a phase of 180 degrees can be acquired through the photogate (PG_B) switch of tab B.

[0079] In summary, in accordance with a pixel structure implemented so that a shared area (350) exists between adjacent pixels according to an embodiment of the present disclosure, a signal with an inverted phase can be obtained in a row unit, and a signal with the same phase can be obtained in a column unit.

[0080]

[0081]

[0082] Referring to Equation 6, we can see that we can obtain an inverted output for each row. On the other hand, we can obtain a fixed output for each column.

[0083] FIG. 4 is a drawing illustrating a ToF pixel structure according to another embodiment of the present disclosure.

[0084] In Fig. 3, a 2-tap pixel structure based on a shared area is disclosed, while in Fig. 4, a 4-tap pixel structure based on a shared area is disclosed.

[0085] Figure 4 (a) shows a structure in which two tabs are added to the pixel structure of Figure 3 described above.

[0086] In (a) of Fig. 4, based on the basic unit, four tabs are sequentially arranged: tab B (first tab), tab A (second tab), tab B (third tab), and tab A (fourth tab).

[0087] Based on the plan view of the pixel basic unit shown in (a) of Fig. 4, the first node OD ) Tab A is placed on the left, and Tab B is placed on the right.

[0088] Meanwhile, in the present disclosure, the second node (Node A ), tab A is placed on the right side as described above, and tab B is placed on the left side. The tab B added in this way is different from the aforementioned Fig. 3.

[0089] In addition, the present disclosure provides a third node (Node B ), tab B is placed on the left as above, and tab A is placed on the right. The added tab A is different from the aforementioned Fig. 3.

[0090] Meanwhile, the first tap (tap B) can be connected to the third pixel via the photogate switch (PG_B). The second tap (tap A) can be connected to the first pixel via the photogate switch (PG_A). The third tap (tap B) can be connected to the second pixel via the photogate switch (PG_B). Finally, the fourth tap (tap A) can be connected to the fourth pixel via the photogate switch (PG_A).

[0091] Based on this tab structure and the arrangement relationship of the photogate switch, the pixel structure of Fig. 4 (a) can obtain a signal of inverted phase in the row unit, as in Fig. 3.

[0092] Meanwhile, based on the arrangement relationship of the tab structure and the photogate switch, the pixel structure of Fig. 4 (a) can obtain a signal of inverted phase even in column units, unlike Fig. 3.

[0093]

[0094]

[0095]

[0096]

[0097] Referring to mathematical equations 7 and 8 of Fig. 4 (a), when readout is performed simultaneously from tabs A and B, mismatch can be eliminated at the column level. That is, by changing the positions of tabs A and B, outputs with a 0-degree phase and a 180-degree phase can be output alternately in one column.

[0098] In this respect, Figures 3 and 4 differ. Specifically, while Figure 3 features pixel overlap, Figure 4 also enables column page swaps in addition to pixel overlap. This eliminates or minimizes not only row-level deviations but also column-level deviations.

[0099] Meanwhile, when applying the arrangement relationship of the photogate switch as shown in FIG. 4 of the present disclosure, there is no need for additional metal routing or cross-platform metal routing as in the past when designing a pixel structure. Therefore, problems arising from including metal routing or applying cross-platform metal routing can be prevented.

[0100] In addition, (b) to (d) of FIG. 4 illustrate examples of output terminal configurations at each node illustrated in (a) of FIG. 4.

[0101] Figure 4 (b) shows the first node (Node OD ) shows an example of the configuration of the output terminal. Fig. 4 (c) shows the second node (Node A ) shows an example of the configuration of the output terminal. Fig. 4 (d) shows the third node (Node B ) is an example of the configuration of the output terminal. However, this is only an example of the circuit configuration of the output terminal at the corresponding node and is not limited thereto.

[0102] FIGS. 5 and 6 are drawings illustrating a schematic type according to an embodiment of the present disclosure.

[0103] Figures 5 and 6 illustrate the layout of the pixel structure for each circuit type of the present disclosure.

[0104] Here, for convenience of explanation, FIGS. 5 and 6 are described based on the pixel structure of FIG. 4, but are not limited thereto.

[0105] First, Fig. 5 (a) shows the first circuit diagram type. Fig. 5 (b) shows the first circuit diagram type part of Fig. 5 (a) on the pixel structure layout.

[0106] Referring to (b) of Fig. 5, the first circuit diagram type can be defined as a polygonal shape. The polygonal shape can include a rectangle, a square, etc.

[0107] If a ToF sensor is implemented with the pixel layout illustrated in (b) of Fig. 5, the regularity of signal output of PG_A and PG_B within the basic pixel unit, i.e., the 2x2 array, can be guaranteed. However, the pixel layout according to the type of the first circuit may have relatively lower layout efficiency compared to (b) of Fig. 6 described later.

[0108] However, Fig. 6 (a) shows the second circuit diagram type. Fig. 6 (b) shows the second circuit diagram type part of Fig. 6 (a) on the pixel structure layout.

[0109] Meanwhile, referring to (b) of Fig. 6, the second circuit diagram type can be defined as a shape other than a polygon, for example, a trapezoidal shape.

[0110] If a ToF sensor is implemented with the pixel layout shown in (b) of Fig. 6, the efficiency of the layout of PG_A and PG_B within the basic pixel unit, i.e., the 2x2 array, can be improved, for example, the driving route of PG_A and PG_B can be simplified (e.g., using 3 lines instead of 4 lines). However, depending on the pixel layout type in the first circuit, the output of the signal to be processed by the switch through the photogate switch can be complicated. This is due to the zigzag connection, which can complicate the operation.

[0111] Meanwhile, as illustrated in (c) of FIG. 6, when a mirror type photogate (PG) switch (620) is used, the number of photogates can be reduced. For example, referring to (b) of FIG. 6, one photogate (PG) switch is placed between two photodiodes, but if the mirror type is utilized, only one photogate (PG) switch (620) can be placed between four photodiodes (610). In this way, by reducing the number of photogate (PG) switches, it is advantageous in securing space, and thus the degree of freedom in design can be increased. In addition, the efficiency of the circuit can be improved.

[0112] FIGS. 7 to 10 are drawings illustrating a physical pixel structure according to an embodiment of the present disclosure.

[0113] In conventional pixel structures, pixels are physically separated from each other by using Shallow Trench Isolation (STI) between adjacent pixels.

[0114] In Fig. 7, a pixel structure according to a first embodiment is disclosed. At this time, Fig. 7 (a) may represent a plan view, and Fig. 7 (b) may represent a cross-sectional view.

[0115] Fig. 7 is basically the same as the conventional pixel structure described above. That is, referring to (a) and (b) of Fig. 7, it can be seen that adjacent pixels are physically separated based on STI.

[0116] In the present disclosure, the sensitivity against the same pitch can be improved by using an adjacent pixel overlapping structure, i.e., a shared area between adjacent pixels, similar to pixel binning, which groups or combines multiple pixels and processes them as a single large pixel.

[0117] In addition, according to the adjacent pixel overlapping structure of the present disclosure, the directional signals (left, right) of the photogates (PG_A, PG_B) can be simultaneously stored in a storage node. Here, the directional signal can refer to a signal having a slight difference in current and voltage depending on the left and right arrangement of the switch in a semiconductor process, for example.

[0118] Even in the first embodiment, although adjacent pixels are separated from each other by the STI process, the physical separation through STI can be artificially connected by connecting adjacent gates (711, 712) with metal.

[0119] In Fig. 8, a pixel structure according to a second embodiment is disclosed. Similarly, Fig. 8 (a) may represent a plan view, and Fig. 8 (b) may represent a cross-sectional view.

[0120] Referring to (a) and (b) of FIG. 8, a shared area (813) may exist between adjacent pixels, i.e., a first pixel (811) and a second pixel (812). In this case, the shared area (813) may be a pixel.

[0121] A gate called a photogate (PG) may be connected between the first pixel (811) and the shared pixel (813) through metal routing. Similarly, a gate called a photogate (PG) may be connected (i.e., merged) between the second pixel (812) and the shared pixel through metal routing.

[0122] Therefore, in the second embodiment, unlike the first embodiment, a shared pixel (813) exists between adjacent pixels (811, 812), and since this shared pixel (813) plays the same role as an adjacent pixel of the target pixel, it is expressed as overlapping. In this way, since the shared pixel (813) exists, STI processing between adjacent pixels through STI may not be necessary, as in the first embodiment.

[0123] Additionally, the second embodiment is characterized by having a smaller number of photodiodes (PDs) than the first embodiment. While four photodiodes (PDs) were required to connect two gates in the first embodiment, only three photodiodes (PDs) may be sufficient to connect two gates in the second embodiment.

[0124] A third embodiment is illustrated in Fig. 9. The basic concept of this third embodiment is similar to that of the second embodiment of Fig. 8.

[0125] In the second embodiment, for example, as illustrated in FIG. 8, an N+ doping layer may be formed in the active region below the storage gate (SG) (821) and / or around the photodiode (PD) between the first pixel (811) and the shared pixel (813). However, the N+ doping layer formed in this manner may induce, for example, a dark current.

[0126] Therefore, in Fig. 9, unlike Fig. 8, a layout structure is proposed that minimizes the aforementioned dark current.

[0127] In the second embodiment described above, the photogate (PG) is connected by metal routing, but in the third embodiment, the gates are merged and the N-type junction diode under the storage gate can be extended to be connected to the photogate (PG). Through this, in the third embodiment, the formation of the N+ doping layer can be prevented, thereby minimizing the induction of dark current.

[0128] Meanwhile, in the second or third embodiment, since the structure of the pixels is an overlapping structure including a shared area, a shared pixel (A, B, C) is placed between each pixel, such as 1-A-2-B-3-4-C-5, so there is no need for a physical separation process of adjacent pixels through an STI process.

[0129] Meanwhile, Fig. 10 shows a cross-sectional view between A-A' in (a) of Fig. 8 and between B-B' in (a) of Fig. 9.

[0130] FIG. 11 is a waveform diagram illustrating signal processing in a ToF pixel according to an embodiment of the present disclosure.

[0131] The signal waveform of the ToF pixel shown in (a) of Fig. 11 is divided into a single first signal period (global period) and a repetitive second signal period (iteration period).

[0132] In the above, the first signal section may be, for example, a global reset section.

[0133] Referring to (a) of Fig. 11, the first signal section may include a global reset, modulation & integration, and anti-blooming section.

[0134] On the other hand, the repetitive second signal period may include reset sampling, signal transfer, signal sampling / analog-to-digital conversion, and blank periods.

[0135] Meanwhile, in relation to the present disclosure, the output (PGA / B) (1110) from the A tap and the B tap can be obtained in the first signal section.

[0136] Figure 11 (b) is an enlarged waveform diagram of the output (PGA / B) (1110) from the A and B taps.

[0137] Referring to (b) of Fig. 11, the outputs of PG_A and PG_B may have waveforms with phases inverted from each other.

[0138] While the present disclosure has been described as an example of a specific region being shared between two adjacent or adjacent pixels, the present disclosure is not necessarily limited to this. As described above, if the specific region is shared between adjacent pixels, it does not operate (function) as a pixel. However, under certain predefined conditions, the specific region may operate as a pixel, just like other pixels.

[0139] The ToF-based image sensor and its operating method according to the present disclosure described above can be applied to various fields. For example, the ToF-based image sensor and its operating method according to the present disclosure can be applied to or utilized in devices used in various fields such as automobiles, robots, industrial automation, eXtended Reality, and environmental monitoring.

[0140] Although the present invention has been described above with reference to embodiments thereof, it will be readily understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

[0141] The ToF sensor technology according to at least one of the various embodiments of the present disclosure can be utilized in various image sensor technologies such as Face ID, automotive cameras, and other industrial cameras, as well as in various electronic devices requiring the ToF sensor.

Claims

1. A pixel structure including a plurality of pixels that sense a phase difference in a received image signal is formed, A specific area is formed between the first pixel and the second pixel among the plurality of pixels, The above specific area is an area shared by the first pixel and the second pixel, ToF (Time of Flight) sensor.

2. In claim 1, In the shared area, at least one photodiode and a photogate for the first pixel and the second pixel are formed, respectively. ToF sensor.

3. In claim 2, Each photogate formed in the above shared area, extending to the photogate formed in each of the first and second pixels, ToF sensor.

4. In claim 3, The above pixel structure is, The phase difference between the first pixel and the second pixel is reversed in the row unit through the shared area. ToF sensor.

5. In claim 4, The above pixel structure is, The phase difference between the first pixel and the second pixel is reversed in the column unit through the shared area. ToF sensor.

6. In claim 3, The above extension is, It is made using a junction diode under the storage gate, The above pixel structure is, N+ is not formed in the active area around the photodiode, ToF sensor.

7. In claim 1, The photogate formed in the above shared area is The photogates of the first and second pixels are connected to the metal, ToF sensor.

8. In claim 1, In the above pixel structure, Between the first pixel, the shared area and the second pixel, there is a 4-tap structure. The first and second tabs are arranged sequentially and alternately, Each tab is connected to the output terminal of a different pixel at the column level. ToF sensor.

9. In claim 1, The above shared area is, Either pixel or non-pixel, ToF sensor.

10. In claim 1, The above pixel structure is, There is no physical separation between adjacent pixels according to the STI (Shallow Trench Isolation) process. ToF sensor.

Images