JP2017084930A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus having pixels having photoelectric conversion parts separated in mutually different directions that prevents incident light to each photoelectric conversion part from being varied caused by reflection light generated by a gate electrode when oblique light is incident in a case where disposition of gate electrodes is different between pixels.SOLUTION: In the imaging apparatus having a first pixel 100A and a second pixel 100B having photoelectric conversion parts separated in mutually different directions, gate electrodes 302A, 312A of a transfer transistor in the first pixel and gate electrodes 302B, 312B of a transfer transistor in the second pixel are disposed in a translational symmetry.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an imaging apparatus.

  Conventionally, a technique for acquiring a focus detection signal and an imaging signal using one pixel is known.

  Patent Document 1 discloses an imaging apparatus having an imaging element in which one microlens for each pixel and a plurality of photoelectric conversion units divided in different directions are formed. Specifically, the imaging element has a first pixel and a second pixel, and a photoelectric conversion unit PD that is divided into M1 in the x direction and divided into N2 in the y direction is formed in the first pixel.

JP 2012-235444 A

  However, Patent Document 1 does not describe the configuration of the transfer transistor. When the photoelectric conversion unit is divided into a plurality of parts in different directions as in Patent Document 1, it may be possible to arrange the transfer transistors at different positions in accordance with the division direction. When arranged in the portion, the arrangement of the gate electrode is different for each pixel. For this reason, there is a possibility that variations in the amount of light incident on each photoelectric conversion unit due to the reflected light generated by the gate electrode when oblique light is incident.

  The present invention is an imaging apparatus having a plurality of pixels arranged on a light receiving surface, wherein the plurality of pixels are separated in only a first direction in a plan view, and each separated photoelectric element. A first pixel having a transfer transistor for transferring the charge generated in the conversion unit to the charge holding unit, and two photoelectric conversion units separated only in a second direction different from the first direction in plan view Including a second pixel having a transfer transistor for transferring the charge generated in each photoelectric conversion unit to the charge holding unit, and a gate electrode of the transfer transistor in the first pixel and a gate electrode of the transfer transistor in the second pixel, It is characterized by being arranged in translational symmetry.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress the dispersion | variation in the incident amount of the light between photoelectric conversion parts in the imaging device by which the pixel from which a pupil separation direction differs is distribute | arranged.

Block diagram of imaging device Pixel circuit diagram Plane schematic diagram of the pixel Cross-sectional schematic diagram of the pixel Plane schematic diagram of the pixel Plane schematic diagram of the pixel Plane schematic diagram of the pixel

Example 1
An embodiment of an imaging apparatus applicable to the present invention will be described with reference to FIGS. Parts denoted by the same reference numerals in the drawings indicate the same element or the same region.

  FIG. 1 is a block diagram of an imaging apparatus 101 that is an embodiment of the present invention. The imaging apparatus 101 includes a pixel unit 102, a drive pulse generation unit 103, a vertical scanning circuit 104, a signal processing unit 105, an output unit 106, and a vertical signal line 107.

  The pixel unit 102 includes a plurality of pixels 100 on the light receiving surface that convert light into an electric signal and output the converted electric signal. The plurality of pixels 100 are arranged in a matrix. Here, the X direction is described as the alignment direction in the row of the pixels 100, and the Y direction is described as the alignment direction in the column of the pixels 100.

  The drive pulse generator 103 generates a drive pulse. The vertical scanning circuit 104 receives the drive pulse from the drive pulse generation unit 103 and supplies a control pulse to each pixel. The driving pulse supplied here is a pulse for driving the transfer transistor and a pulse for driving the reset transistor.

  A plurality of vertical signal lines 107 are arranged, and each vertical signal line 107 is arranged for each pixel column of the pixel unit 102. Signals output in parallel via the vertical signal line 107 are input to the signal processing unit 105. Then, the signals output in parallel from the plurality of pixel columns are serialized and transmitted to the output unit 106. Further, the signal processing unit 105 may include a column circuit that performs signal amplification, AD conversion, and the like.

  FIG. 2 shows an example of an equivalent circuit of the pixel 100, and FIG. 3 shows a schematic plan view of the pixel 100. In the present embodiment, the polarity of the charge used as the signal charge among the charge pairs generated in the photoelectric conversion unit 201 and the photoelectric conversion unit 211 is referred to as a first conductivity type. Subscripts A, B, C, and D are used to identify each member, but portions having similar functions will not be described. When it is necessary to distinguish between the two, a description is given with a suffix.

  In this embodiment, as an example, the charge of the first conductivity type is assumed to be an electron, and the charge of the second conductivity type opposite to the first conductivity type is assumed to be a hole. However, the present invention is not limited to this. It may be replaced.

  The photoelectric conversion unit 201 and the photoelectric conversion unit 211 generate charge pairs corresponding to incident light by photoelectric conversion. For example, a photodiode is used for the photoelectric conversion unit 201 and the photoelectric conversion unit 211.

  The transfer transistor 202 transfers electrons generated in the photoelectric conversion unit 201 to a floating diffusion (hereinafter referred to as FD) 203. The transfer transistor 212 transfers electrons generated in the photoelectric conversion unit 211 to the FD 203.

  The FD 203 is shared by the photoelectric conversion unit 201 and the photoelectric conversion unit 211. The FD 203 holds electrons transferred by the transfer transistor 202 and the transfer transistor 212.

  The amplification transistor 205 has a gate electrode connected to the FD 203, and amplifies and outputs a signal based on the electrons transferred to the FD 203 by the transfer transistor 202 and the transfer transistor 212. More specifically, the electrons transferred to the FD 203 are converted into a voltage corresponding to the amount, and an electric signal corresponding to the voltage is output to the vertical signal line 107 via the amplification transistor 205. The amplification transistor 205 constitutes a source follower circuit together with a current source (not shown). A selection transistor may be further arranged on the vertical line side of the amplification transistor 205.

  The reset transistor 204 resets the voltage at the input node of the amplification transistor 205. In FIG. 2, both the amplification transistor 205 and the reset transistor 204 are shared by the photoelectric conversion unit 201 and the photoelectric conversion unit 211.

  The pixel 100 having such a configuration can be used as an imaging pixel or a pixel 100 having a function other than imaging (for example, focus detection by a phase difference detection method).

  When an imaging output is obtained from the pixel 100, an imaging signal is obtained by transferring signal charges generated in the photoelectric conversion unit 201 and the photoelectric conversion unit 211 to the FD 203. The signal is output as a signal of the pixel 100 to the signal processing unit 105 via the vertical signal line 107.

  Further, when obtaining a focus detection signal, only the signal charge generated in the photoelectric conversion unit 201 or the photoelectric conversion unit 211 is transferred to the FD 203. In a plurality of pixels 100 arranged in a matrix in the pixel unit 102, a signal for focus detection is output by outputting only the signal of one of the two photoelectric conversion units.

  When both signals of the photoelectric conversion unit 201 and the photoelectric conversion unit 211 are required as a focus detection signal, the other photoelectric conversion is performed by subtracting the signal of one photoelectric conversion unit output in advance from the image pickup signal. Part of the signal can be obtained.

  Note that the output method of the focus detection signal and the imaging signal is not limited to the above-described method, and means such as combining after outputting the signals of the photoelectric conversion unit 201 and the photoelectric conversion unit 211 to the outside is also possible. Is possible.

  In addition, although a configuration in which one pixel has one amplification transistor 205 in the plurality of pixels 100 is shown, any configuration in which a plurality of pixels share one amplification transistor 205 is applicable.

  Note that in this embodiment, the FD is used as a charge holding unit to which electrons generated in the photoelectric conversion unit 201 are transferred. However, any configuration that can hold charges may be used. For example, the configuration may be such that electrons generated in the photoelectric conversion unit are transferred to a charge holding unit different from the FD, and the charges held in the charge holding unit are transferred to the FD.

  FIG. 3 shows a schematic plan view of the pixel 100. In FIG. 3, only the photoelectric conversion unit, the transfer transistor, and the FD are schematically shown in each pixel 100, but a transistor for each pixel may be further provided. For example, an amplification transistor that amplifies the pixel signal and a reset transistor that resets the signal of the amplification transistor are arranged in the same active region or in another active region.

  Although not shown in FIG. 3, microlenses are arranged corresponding to each of the plurality of pixels. The microlens enters light into two photoelectric conversion units arranged in each pixel.

  The photoelectric conversion unit, the FD, the source region and the drain region of each transistor are arranged in the active region 300. Note that the first direction and the second direction are different directions, and in this embodiment, the first direction is parallel to the X direction in the figure, and the second direction is parallel to the Y direction in the figure. .

  The pixel 100 includes a pixel 100A (first pixel) shown in FIG. 3A and a pixel 100B (second pixel) shown in FIG. Each of the pixel 100A and the pixel 100B in FIGS. 3A and 3B is separated by an element isolation portion. In the pixel 100A, the photoelectric conversion unit is divided into two parts only in the first direction. In the pixel 100 </ b> B, the photoelectric conversion unit includes at least a portion separated into two only in the second direction.

  In the pixel 100A of FIG. 3A, N-type semiconductor regions 303A, 301A, 311A, and 303B are arranged in the active region 300A. A separation portion 304A is disposed between the N-type semiconductor region 301A and the N-type semiconductor region 311A. The separation unit 304A is provided with a P-type semiconductor region and constitutes PN junction isolation. The separation unit 304 may be provided with LOCOS, STI, or the like.

  A gate electrode 302A and a gate electrode 312A are disposed on the active region 300A. The gate electrode 302A is disposed between the N-type semiconductor region 301A and the N-type semiconductor region 303A, and the gate electrode 312A is disposed between the N-type semiconductor region 311A and the N-type semiconductor region 303B.

  The N-type semiconductor region 301A constitutes a part of the photoelectric conversion unit 201 (201A) in FIG. 2, and the N-type semiconductor region 311A constitutes a part of the photoelectric conversion unit 211 (211A) in FIG. The N-type semiconductor region 303A constitutes the FD 203 (203A) in FIG. 2, and the N-type semiconductor region 303B constitutes the FD 203 (203B) in FIG. The FD 203A holds electrons generated in the photoelectric conversion unit 201A. The FD 203B holds electrons generated in the photoelectric conversion unit 201B. The FD 203A and the FD 203B are electrically connected.

  The N-type semiconductor region 301A, the gate electrode 302A, and the N-type semiconductor region 303A constitute the transfer transistor 202 (202A) in FIG. The N-type semiconductor region 311A, the gate electrode 312A, and the N-type semiconductor region 303B constitute the transfer transistor 212 (212A) in FIG. The transfer transistor 202A transfers the electrons generated in the photoelectric conversion unit 201A to the FD 203A. The transfer transistor 202B transfers electrons generated in the photoelectric conversion unit 201B to the FD 203B. In this embodiment, the transfer direction of electrons generated in the photoelectric conversion unit 201A and the photoelectric conversion unit 211A is different by 180 °. Although FIG. 3 shows a view that is 180 ° different in the Y direction, it may be 180 ° different in the X direction.

  In the pixel 100B of FIG. 3B, N-type semiconductor regions 303C, 301B, 311B, and 303D are arranged in the active region 300B. A separation portion 304B is disposed between the N-type semiconductor region 301B and the N-type semiconductor region 311B. The separation unit 304B is provided with a P-type semiconductor region and constitutes PN junction isolation. The separation unit 304B may be provided with LOCOS, STI, or the like.

  A gate electrode 302B and a gate electrode 312B are disposed on the active region 300B. The gate electrode 302B is disposed between the N-type semiconductor region 303C and the N-type semiconductor region 301B, and the gate electrode 312B is disposed between the N-type semiconductor region 311B and the N-type semiconductor region 303D.

  The N-type semiconductor region 301B constitutes a part of the photoelectric conversion unit 201 (201B) in FIG. 2, and the N-type semiconductor region 311B constitutes a part of the photoelectric conversion unit 211 (211B) in FIG. The N-type semiconductor region 303C constitutes the FD 203 (203C) in FIG. 2, and the N-type semiconductor region 303D constitutes the FD 203 (203D). The FD 203C holds electrons generated in the photoelectric conversion unit 201B. The FD 203D holds electrons generated in the photoelectric conversion unit 211B. The FD 203C and the FD 203D are electrically connected.

  The N-type semiconductor region 301B, the gate electrode 302B, and the N-type semiconductor region 303C constitute the transfer transistor 202 (202B) in FIG. The N-type semiconductor region 311B, the gate electrode 312B, and the N-type semiconductor region 303D constitute the transfer transistor 212 (212B) in FIG. The transfer transistor 202B transfers electrons generated in the photoelectric conversion unit 201B to the FD 203C. The transfer transistor 212B transfers electrons generated in the photoelectric conversion unit 211B to the FD 203D. In this embodiment, the charge transfer directions of the photoelectric conversion unit 201B and the photoelectric conversion unit 211B are different from each other by 180 °. Although FIG. 3 shows a view that is 180 ° different in the Y direction, it may be 180 ° different in the X direction.

  Note that at least part of the N-type semiconductor region 301B and the N-type semiconductor region 311B is separated only in the second direction, and the other regions are only in the first direction or in the direction including the components in the first direction and the second direction. It may be separated. Even in such a configuration, it is possible to obtain phase shift amounts in different directions in the pixel 100A and the pixel 100B.

  Preferably, another region of the pixel 100B is a region between a region separated only in the second direction and a gate electrode that controls charge transfer in each photoelectric conversion unit having each N-type semiconductor region. It is. With such a configuration, even when the gate electrode is a translation target in the pixel 100A and the pixel 100B, the gate width can be easily aligned. Alternatively, the N-type semiconductor region 301B and the N-type semiconductor region 311B of the pixel 100B are separated only in the second direction.

  As described above, the pixel 100A and the pixel 100B have photoelectric conversion portions that are separated into two in different directions. According to such a configuration, when these pixels are used for focus detection, phase shift amounts in different directions can be obtained, and focus detection can be performed with high accuracy. Specifically, for example, from a pixel having a photoelectric conversion unit separated into two in the first direction, it is possible to accurately detect a focus on a subject whose pattern is mainly an edge in the second direction. On the other hand, an accurate focus detection can be performed on a subject having a pattern mainly including an edge in the first direction from a pixel having two photoelectric conversion units separated in the second direction.

  In this embodiment, a configuration in which the first direction and the second direction are orthogonal to each other is shown as an example. Thereby, it is possible to obtain the phase shift amounts in the vertical direction and the horizontal direction.

  Then, it is better to form the N-type semiconductor regions 301A and 311A so as to have the same area in plan view. Thereby, it is possible to suppress variation in the amount of incident light due to the difference in the light receiving area of each photoelectric conversion unit. The same applies to the pixel 100B.

  Further, in this embodiment, the gate electrodes of the transfer transistors of the pixel 100A and the gate electrodes of the transfer transistors of the pixel 100B are arranged so as to be translationally symmetric.

  Here, the translational symmetry means that the gate electrode of the transfer transistor of the pixel 100A overlaps the gate electrode of the transfer transistor of the pixel when translated in the same direction at a constant interval (for example, pixel pitch: photoelectric conversion unit pitch). .

  With such a configuration, it is possible to suppress variation in the amount of light incident on each photoelectric conversion unit due to reflected light generated by the gate electrode when oblique light is incident. Therefore, when the pixel 100A and the pixel 100B are used for imaging, it is possible to suppress variation in the color ratio of each pixel.

  Furthermore, when forming an N-type semiconductor region constituting a transfer transistor in the pixel manufacturing process, it is possible to improve the uniformity of the impurity profile of each pixel when oblique ion implantation is performed after the gate electrode is formed. It is. As a result, it is possible to suppress the asymmetry between the pixels of the transfer characteristics.

  The gate widths (W) of the gate electrode 302A and the gate electrode 302B, and the gate electrode 312A and the gate electrode 312B on the photoelectric conversion portion side are preferably formed to be equal. As a result, it is possible to suppress variations in transfer characteristics between pixels.

  Note that in the pixel 100A, the N-type semiconductor region 301A, the gate electrode 302A, the N-type semiconductor region 303A, the N-type semiconductor region 311A, the gate electrode 312A, and the N-type semiconductor region 303B may be arranged in different active regions. Similarly, in the pixel 100B, the N-type semiconductor region 301B, the gate electrode 302B, the N-type semiconductor region 303C, the N-type semiconductor region 311B, the gate electrode 312B, and the N-type semiconductor region 303D may be arranged in different active regions. .

  4A is a schematic cross-sectional view taken along line AB in FIG. 3A, and FIG. 4B is a schematic cross-sectional view taken along line CD in FIG. is there. Each semiconductor region is disposed on a semiconductor substrate 313. In the following description, when describing the positional relationship between the semiconductor regions, the direction toward the deep part of the semiconductor substrate 313 is based on the boundary between one main surface of the semiconductor substrate 313 where the multilayer wiring structure is arranged and the interlayer insulating film. Is the downward direction, and the opposite direction is the upward direction.

  4A and 4B, a P-type semiconductor region 314 is disposed on the N-type semiconductor region 306 of the pixel 100. A P-type semiconductor region 305 having a high impurity concentration is disposed as a channel stop region below the element isolation portion 310.

  In FIG. 4A, the N-type semiconductor region 301A and the P-type semiconductor region 314 form a PN junction. Further, a P-type semiconductor region 307 is disposed on the main surface side of the N-type semiconductor region 301A. The photoelectric conversion portion 201A in FIG. 2 forms an embedded photodiode by these semiconductor regions. Similarly, the N-type semiconductor region 311A and the P-type semiconductor region 314 form a PN junction. Further, a P-type semiconductor region 307 is also disposed on the main surface side of the N-type semiconductor region 311A. The photoelectric conversion unit 211A in FIG. 2 forms an embedded photodiode by these semiconductor regions.

  A separation portion 304A is disposed between the N-type semiconductor region 301A and the N-type semiconductor region 311A. Here, the separation portion 304 </ b> A is a P-type semiconductor region 314. In plan view, the N-type semiconductor region 301A and the N-type semiconductor region 311A are separated by PN junction separation. Note that the N-type semiconductor region 301A and the N-type semiconductor region 311A are separated by the P-type semiconductor region 314 in the deep portion of the semiconductor substrate, but the N-type semiconductor region 301A and the N-type semiconductor region 311A are connected in the deep portion of the semiconductor substrate. Thus, an N-type semiconductor region may be arranged.

  The N-type semiconductor region 303A constitutes the FD 203A in FIG. The N-type semiconductor region 303B constitutes the FD 203B in FIG. Each of the N-type semiconductor region 303A and the N-type semiconductor region 303B forms a PN junction with the P-type semiconductor region 314, and holds electrons transferred from each photoelectric conversion unit by a capacitor formed by the PN junction.

  The gate electrode 302A is disposed on the semiconductor substrate 313 with the insulating film 308 interposed therebetween. The N-type semiconductor region 301A constitutes the drain region of the transfer transistor 202A in FIG. 2, and the N-type semiconductor region 303A constitutes the source region of the transfer transistor 202A in FIG.

  The gate electrode 312A is disposed on the semiconductor substrate 313 with the insulating film 308 interposed therebetween. The N-type semiconductor region 311A constitutes the drain region of the transfer transistor 212A in FIG. 2, and the N-type semiconductor region 303B constitutes the source region of the transfer transistor 212A in FIG.

  In FIG. 4B, the N-type semiconductor region 301B and the P-type semiconductor region 314 form a PN junction. Further, a P-type semiconductor region 307 is disposed on the main surface side of the N-type semiconductor region 301B. The photoelectric conversion unit 201B in FIG. 2 forms an embedded photodiode with these semiconductor regions. Similarly, the N-type semiconductor region 311B and the P-type semiconductor region 314 constitute a PN junction. Further, a P-type semiconductor region 307 is also disposed on the main surface side of the N-type semiconductor region 311B. The photoelectric conversion unit 211B in FIG. 2 forms an embedded photodiode by these semiconductor regions.

  A separation portion 304B is disposed between the N-type semiconductor region 301B and the N-type semiconductor region 311B. Here, the separation portion 304B is a P-type semiconductor region 314, and the N-type semiconductor region 301B and the N-type semiconductor region 311B are separated by PN junction separation.

  The N-type semiconductor region 303C constitutes the FD 203C in FIG. The N-type semiconductor region 303D constitutes the FD 203D in FIG. Each of the N-type semiconductor region 303C and the N-type semiconductor region 303D forms a PN junction with the P-type semiconductor region 314, and holds electrons transferred from each photoelectric conversion unit by a capacitor formed by the PN junction.

  The gate electrode 302B is disposed on the semiconductor substrate 313 with the insulating film 308 interposed therebetween. The N-type semiconductor region 301B constitutes the drain region of the transfer transistor 202B in FIG. 2, and the N-type semiconductor region 303C constitutes the source region of the transfer transistor 202B in FIG.

  The gate electrode 312B is disposed on the semiconductor substrate 313 with the insulating film 308 interposed therebetween. The N-type semiconductor region 311B constitutes the drain region of the transfer transistor 212B in FIG. 2, and the N-type semiconductor region 303D constitutes the source region of the transfer transistor 212B in FIG.

  Note that the P-type semiconductor region 314 is preferably a P-type semiconductor region having a lower impurity concentration than the P-type semiconductor region 305. Capacitance of the FD 203A and the FD 203B can be reduced by pn junction of the P-type semiconductor region 314 and the N-type semiconductor region.

  As a result, the capacitance value of the input node of the amplification transistor 205 (not shown) is reduced, and the gain of the amplification transistor 205 can be improved.

  According to the above configuration, by arranging the transfer gates in translational symmetry, the amount of light incident on the photoelectric conversion unit varies from pixel to pixel by irradiating the transfer gate electrode with oblique incident light. It becomes possible to suppress.

(Example 2)
In the second embodiment, the configuration of FIGS. 1 and 2 is the same as that of the first embodiment. 3 and FIG. 5 have corresponding numbers. Next, the difference between the first embodiment and the second embodiment will be described. In Example 1, the transfer directions of electrons generated in the photoelectric conversion unit 201A and the photoelectric conversion unit 211A are different by 180 °. Similarly, the transfer direction of electrons generated in the photoelectric conversion unit 201B and the photoelectric conversion unit 211B is different by 180 °.

  However, in this embodiment, as shown in FIG. 5A, the transfer directions of electrons generated in the photoelectric conversion unit 201A and the photoelectric conversion unit 211A are different by 90 °. Similarly, as shown in FIG. 5B, the transfer directions of electrons generated in the photoelectric conversion unit 201B and the photoelectric conversion unit 211B are different by 90 °.

  Even with the above configuration, by arranging the transfer gates in translational symmetry, it is possible to prevent the amount of light incident on the photoelectric conversion unit from changing for each pixel by irradiating the transfer gate electrode with oblique incident light. It becomes possible to do.

(Example 3)
In the third embodiment, the configuration of FIGS. 1 and 2 is the same as that of the first embodiment. 3 and FIG. 6 have corresponding numbers. Next, the difference between the first embodiment and the third embodiment will be described. In Example 1, the transfer direction of electrons generated in the photoelectric conversion unit 201A and the photoelectric conversion unit 211A is different by 180 ° in the Y direction or 180 ° in the X direction. However, in the third embodiment, as shown in FIG. 6A, the transfer direction of electrons generated in the photoelectric conversion unit 201A and the photoelectric conversion unit 211A differs by 180 ° in an oblique direction with respect to the X direction. Similarly, as shown in FIG. 6B, the transfer direction of electrons generated in the photoelectric conversion unit 201B and the photoelectric conversion unit 211B differs by 180 ° in an oblique direction with respect to the X direction.

  Even with the above configuration, by arranging the transfer gates in translational symmetry, it is possible to prevent the amount of light incident on the photoelectric conversion unit from changing for each pixel by irradiating the transfer gate electrode with oblique incident light. It becomes possible to do.

Example 4
In the fourth embodiment, the configuration of FIGS. 1 and 2 is the same as that of the first embodiment. The corresponding members in FIGS. 3 and 7 are given the same numbers. Next, the difference between the first embodiment and the fourth embodiment will be described. In Example 1, the first direction was parallel to the X direction, and the second direction was parallel to the Y direction. On the other hand, in Example 4, the first direction and the second direction are oblique to the X direction and the Y direction. Preferably, the first direction and the second direction are orthogonal to each other.

  FIG. 7A shows a schematic plan view of the pixel 100A, and FIG. 7B shows a schematic plan view of the pixel 100B. In the pixel 100A of FIG. 7A, the N-type semiconductor region 301A and the N-type semiconductor region 311A are separated in the first direction in plan view. In the present embodiment, the first direction is a direction that advances in the -Y direction as it advances in the X direction.

  In the pixel 100B of FIG. 7B, the N-type semiconductor region 301B and the N-type semiconductor region 311B are separated in the second direction in plan view. In the present embodiment, the second direction is a direction that advances in the Y direction as it advances in the X direction.

  In this embodiment, the oblique direction in the first direction is preferably a direction in which the N-type semiconductor region 301A and the N-type semiconductor region 311A are point-symmetric.

  According to such a separation method, as described above, the N-type semiconductor region 301A and the N-type semiconductor region 311A have the same area.

  In this embodiment, the first direction and the second direction are orthogonal to each other and form an angle of 45 ° with respect to the X direction. According to such a configuration, when the gate electrode of the transfer transistor is arranged, the shape of the photoelectric conversion unit is difficult to change the gate width. Furthermore, here, an example in which the photoelectric conversion unit is an isosceles triangle is given as an example. In such a case, in the photoelectric conversion unit 201, the outer edge in the X direction and the outer edge in the Y direction have the same length. Therefore, even when the separation directions are different, the gate width of the gate electrode of the transfer transistor is hardly changed.

  Even with the above configuration, by arranging the transfer gates in translational symmetry, it is possible to prevent the amount of light incident on the photoelectric conversion unit from changing for each pixel by irradiating the transfer gate electrode with oblique incident light. It becomes possible to do.

  Further, according to such a configuration, when each signal of each photoelectric conversion unit is used for focus detection, the phase shift amount in a different direction in the oblique direction can be obtained, and focus detection can be performed with high accuracy. it can. Specifically, for example, from a pixel having a photoelectric conversion unit separated into two in the first direction of the present embodiment, accurate focus detection can be performed on a subject whose pattern is mainly the edge of the second direction of the present embodiment. It becomes possible. On the other hand, from the pixel having the photoelectric conversion unit separated into two in the second direction of the present embodiment, accurate focus detection can be performed on the subject having the pattern mainly including the edge in the first direction of the present embodiment.

DESCRIPTION OF SYMBOLS 100 Pixel 101 Imaging device 201 Photoelectric conversion part 211 Photoelectric conversion part 202 Transfer transistor 212 Transfer transistor 203 FD

Claims (15)

An imaging device having a plurality of pixels arranged on a light receiving surface,
The plurality of pixels are
A first pixel having two photoelectric conversion units separated in only the first direction in plan view in the same pixel, and a transfer transistor for transferring charges generated in each separated photoelectric conversion unit to the charge holding unit; and , Two photoelectric conversion units including at least a portion separated only in a second direction different from the first direction in plan view in the same pixel, and charges generated in each separated photoelectric conversion unit are transferred to the charge holding unit A second pixel having a transfer transistor to
An imaging apparatus, wherein a gate electrode of a transfer transistor in the first pixel and a gate electrode of a transfer transistor in the second pixel are arranged in translational symmetry.   The imaging apparatus according to claim 1, wherein the two photoelectric conversion units of the second pixel are separated only in the second direction. The plurality of pixels are arranged in a matrix,
The imaging apparatus according to claim 1, wherein the first direction and the second direction are oblique directions with respect to an arrangement direction in a row of pixels.   The imaging apparatus according to claim 3, wherein the first direction and the second direction are orthogonal to each other and form an angle of 45 ° with respect to the arrangement direction of the pixel rows. The plurality of pixels are arranged in a matrix,
The imaging apparatus according to claim 1, wherein the first direction is parallel to an arrangement direction in a row of pixels, and the second direction is parallel to an arrangement direction in a column of pixels. . In each of the first pixel and the second pixel,
Of the two separated photoelectric conversion units, the transfer direction when transferring the charge generated in one photoelectric conversion unit to the charge holding unit and the charge generated in the other photoelectric conversion unit are transferred to the charge holding unit The imaging apparatus according to claim 1, wherein the transfer direction at the time is a direction different by 180 °. In each of the first pixel and the second pixel,
Of the two separated photoelectric conversion units, the transfer direction when transferring the charge generated in one photoelectric conversion unit to the charge holding unit and the charge generated in the other photoelectric conversion unit are transferred to the charge holding unit The imaging device according to claim 2, wherein a transfer direction at the time is parallel to an arrangement direction of the pixels in a row. In each of the first pixel and the second pixel,
Of the two separated photoelectric conversion units, the transfer direction when transferring the charge generated in one photoelectric conversion unit to the charge holding unit and the charge generated in the other photoelectric conversion unit are transferred to the charge holding unit The image pickup apparatus according to claim 3, wherein a transfer direction at the time is parallel to an arrangement direction in the pixel row. In each of the first pixel and the second pixel,
Of the two separated photoelectric conversion units, the transfer direction when transferring the charge generated in one photoelectric conversion unit to the charge holding unit and the charge generated in the other photoelectric conversion unit are transferred to the charge holding unit The imaging apparatus according to claim 5, wherein a transfer direction at the time is an oblique direction with respect to an arrangement direction of the pixels in a row. In each of the first pixel and the second pixel,
Of the two separated photoelectric conversion units, the transfer direction when transferring the charge generated in one photoelectric conversion unit to the charge holding unit and the charge generated in the other photoelectric conversion unit are transferred to the charge holding unit The imaging apparatus according to claim 5, wherein the transfer direction is 90 ° different from that at the time. In each of the first pixel and the second pixel,
11. The imaging apparatus according to claim 1, wherein each of the two separated photoelectric conversion units has the same area in a plan view.   The imaging according to any one of claims 1 to 11, wherein a gate electrode of the transfer transistor in the first pixel and a gate electrode of the transfer transistor in the second pixel have the same gate width. apparatus.   The imaging apparatus according to claim 1, further comprising a plurality of microlenses corresponding to each of the plurality of pixels.   The imaging apparatus according to claim 13, wherein the first pixel and the second pixel are used for focus detection by a phase difference detection method.   The imaging device according to claim 14, wherein the first pixel and the second pixel are used for imaging.

Images