JP2008124386A - Two branch output solid-state imaging element, and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two branch output solid-state imaging element for picking up an image whose quality is high by satisfactorily carrying out charge distribution. <P>SOLUTION: This two branch output solid-state imaging element is provided with: a horizontal charge transferring part 103; a charge branching part 120 for distributing signal charge transferred along the horizontal charge transfer path 103 alternately to two directions; and two branch transfer paths 104 and 105 installed corresponding to the two directions, wherein a distribution electrode film 120a installed in the charge branch part 120 is shaped like a triangle by making the base section adjacent to the end of the horizontal charge transfer path 103, and making one of the two oblique sides adjacent to one branch transfer path 104, and making the other oblique side adjacent to a branch transfer path 105, and a protruding electrode film 120c separating branch transfer paths 104 and 105 from a vertex faced to the base shaped like a triangle is extended. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a CCD (Charge Coupled Devices) type solid-state imaging device and imaging apparatus in which an output end of a charge transfer path (transfer register) is branched in parallel into two branch transfer paths, and in particular, transfer charges. The present invention relates to an output two-branch solid-state imaging device and an imaging device that can be well distributed to each branch transfer path without remaining transfer.

  In recent years, CCD-type solid-state imaging devices have increased in number of pixels with the progress of semiconductor microfabrication technology, and have been equipped with millions of pixels or more. For this reason, the number of transfer stages of the horizontal charge transfer path for reading the picked-up image signal increases, and it is necessary to increase the transfer drive frequency in order to read the picked-up image signal at high speed. However, when the transfer drive frequency is increased, there is a problem that the waveform of the voltage value signal output from the output amplifier is disturbed.

  Therefore, the output end of the horizontal charge transfer path is branched in parallel, and the transfer drive of the horizontal charge transfer path is performed by a high-frequency signal, and the signal charge sequentially transferred on the horizontal charge transfer path is transferred to the charge distribution section (charge branch section). ), A technique has been developed in which the drive frequency of the branch transfer path is halved from the drive frequency of the horizontal charge transfer path by sequentially allocating to each branch transfer path (for example, Patent Documents 1 and 2).

  FIG. 7 is a schematic view of the surface around the charge distribution unit described in Patent Document 1. In this prior art, the output end portion of the horizontal charge transfer path 1 is branched into two branch transfer paths 2 and 3, and the signal charge transferred on the horizontal charge transfer path 1 is alternately branched by the charge distribution section 4. They are distributed to the transfer paths 2 and 3.

  Each of the horizontal charge transfer path 1, the branch transfer path 2, 3 and the charge distribution unit 4 is composed of a buried channel and a transfer electrode film stacked thereon via an insulating layer. The storage electrode film and the barrier electrode film are alternately arranged in the direction.

  The shape of the storage electrode film of the charge distribution unit 4 shown in FIG. 7 is T-shaped. This is because the end A3 on the branch transfer path 2 side is brought closer to the end position A2 on the horizontal charge transfer path 1 side and the branch transfer path 3 side of the charge distribution unit 4. That is, when the signal charge at the position A2 is distributed to the branch transfer path 2, it is easier to distribute the signal charge of the charge distribution unit 4 to the branch transfer path 2 when the position A2 is closer to the position A3. is there.

  However, when the potential for charge distribution is applied to the storage electrode film of the charge distribution unit, the potential at position A2 and the potential at position A3 are the same, so that the signal charge is distributed when charge distribution is performed. When the charge distribution unit 4 distributes the signal charge to the branch transfer path 3 next time, the previous residual charge may be mixed.

  Therefore, in the prior art described in Patent Document 2, as shown in FIG. 8, the shape of the storage electrode film provided in the charge distribution unit 5 is a flat triangle, and the width of the storage electrode film near the position A2 is narrowed. Strengthens the short channel effect. Thereby, the potential in the vicinity of the position A2 has a gradient with respect to the position of the center of gravity of the triangle, and the charge transfer in the charge distribution unit 5 is favorably performed.

Japanese Patent No. 2585604 Japanese Patent No. 2949861

  However, even if the shape of the charge distribution unit 5 is a simple triangle, there is a possibility that residual charges are generated in the charge distribution unit 5. FIG. 9 is a diagram in which a potential portion is calculated when the shape of the storage electrode film of the charge distribution unit 5 is a simple triangle. It can be seen that a flat identical potential region 6 exists in the central portion of the triangular charge distribution portion 5.

  There is no potential gradient in the same potential region 6, and there is a possibility that transfer charges crossing the region 6 are left in the same potential region 6 and mixed into signal charges to be distributed next.

  An object of the present invention is to provide an output two-branch solid-state imaging device and an imaging apparatus that can perform charge distribution satisfactorily.

  The output bifurcated solid-state imaging device of the present invention corresponds to a horizontal charge transfer path, a charge branch section that alternately distributes signal charges transferred along the horizontal charge transfer path in two directions, and the two directions. In the output two-branch type solid-state imaging device including two branch transfer paths provided in the same manner, the shape of the sorting electrode film provided in the charge branch portion is adjacent to the end of the horizontal charge transfer path. One of the two hypotenuses is formed in a triangular shape adjacent to one of the branch transfer paths and the other hypotenuse is adjacent to the other branch transfer path, and the two branch transfers from the apex facing the base of the triangle A protruding electrode film for separating the paths is extended.

  The protruding electrode film of the output bifurcated solid-state imaging device of the present invention is characterized in that it extends to an element separation zone that separates the two branch transfer paths.

  The width of the protruding electrode film of the output bifurcated solid-state imaging device of the present invention is narrower than the width of the barrier electrode film of the two branch transfer paths separated by the electrode film (the length in the direction in which charges cross). It is characterized by that.

  In the output bifurcated solid-state imaging device of the present invention, the triangular shape is a flat isosceles triangle.

  In the output bifurcated solid-state imaging device according to the present invention, when the charge branching unit performs charge distribution, a fixed voltage is applied to the distribution electrode, and the branching is performed without accumulating the signal charge flowing from the horizontal charge transfer path. It is characterized by flowing into one of the transfer paths.

  In the output two-branch solid-state imaging device of the present invention, the signal charge is an electron, and the horizontal charge transfer path, the charge branching section, and the branch transfer path are embedded in an n-type impurity layer. The impurity concentration of the impurity layer is characterized by increasing in the order of horizontal charge transfer path <charge branch portion <branch transfer path.

  The output bifurcated solid-state imaging device of the present invention is characterized in that the width of the horizontal charge transfer path (the length in the direction perpendicular to the charge transfer direction) becomes narrower as it approaches the charge branch portion.

  The image pickup apparatus of the present invention is read from the output two-branch solid-state image pickup device according to any one of the above, drive means for driving the output two-branch solid-state image pickup device, and the output two-branch solid-state image pickup device. And a signal processing means for processing the captured image signal.

  According to the present invention, charge distribution can be performed satisfactorily and a high-quality image can be taken.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a digital camera according to an embodiment of the present invention. The digital camera shown in the figure includes a photographic lens 10, a CCD type solid-state imaging device 100, which will be described in detail later, a diaphragm 12 provided between the two, an infrared cut filter 13, and an optical low-pass filter 14. The CPU 15 that performs overall control of the entire digital camera controls the flash light emitting unit 16 and the light receiving unit 17, controls the lens driving unit 18 to adjust the position of the photographing lens 10 to the focus position, and controls the aperture via the aperture driving unit 19. The exposure amount is adjusted by controlling the opening amount of 12.

  Further, the CPU 15 outputs and drives φ1 to φ5, which will be described later, to the solid-state imaging device 100 via the imaging device driving unit 20, and outputs a subject image captured through the photographing lens 10 as a color signal. An instruction signal from the user is input to the CPU 15 through the operation unit 21, and the CPU 15 performs various controls according to the instruction.

  The electric control system of the digital camera includes an analog signal processing unit 22 connected to the output of the solid-state imaging device 100, and an A / D conversion circuit that converts RGB color signals output from the analog signal processing unit 22 into digital signals. These are controlled by the CPU 15.

  Furthermore, the electric control system of the digital camera includes a memory control unit 25 connected to a main memory (frame memory) 24, a digital signal processing unit 26 that performs interpolation calculation, gamma correction calculation, RGB / YC conversion processing, and the like. A compression / expansion processing unit 27 that compresses the captured image into a JPEG image or expands the compressed image, an integration unit 28 that integrates photometric data and obtains the gain of white balance correction performed by the digital signal processing unit 26, and a detachable unit An external memory control unit 30 to which a recording medium 29 is connected and a display control unit 32 to which a liquid crystal display unit 31 mounted on the back of the camera or the like is connected are connected to each other by a control bus 33 and a data bus 34. Connected and controlled by a command from the CPU 15.

  FIG. 2 is a schematic plan view of the solid-state imaging device 100 shown in FIG. The illustrated solid-state image sensor 100 is an output bifurcated type. In this solid-state imaging device 100, a large number of photodiodes (photoelectric conversion elements) 101 are arranged in a two-dimensional array on a semiconductor substrate, and even-numbered photodiodes 101 are ½ of odd-numbered photodiodes 101. The arrangement is shifted by a pitch (so-called honeycomb pixel arrangement).

  “R”, “G”, and “B” illustrated on each photodiode 101 represent the color of the color filter (red = R, green = G, blue = B) stacked on each photodiode. The diode 101 accumulates signal charges corresponding to the amount of received light of one of the three primary colors. Although an example in which a primary color filter is mounted will be described, a complementary color filter may be mounted.

  In the horizontal direction of the semiconductor substrate surface, vertical transfer electrodes are laid to meander to avoid each photodiode 101. In the semiconductor substrate, a buried channel (not shown) is formed to meander in the vertical direction so as to avoid the photodiode 101 at the side of the photodiode row arranged in the vertical direction. A vertical transfer path (VCCD) 102 is formed by the buried channel and a vertical transfer electrode provided on the buried channel and arranged in a meandering manner in the vertical direction.

  A horizontal transfer path (HCCD) 103 is provided on the lower side of the semiconductor substrate. This horizontal transfer path 103 is also composed of a buried channel and a horizontal transfer electrode provided thereon, and this horizontal transfer path 103 is two-phase driven by transfer pulses φ 1 and φ 2 output from the image sensor driving unit 20. The

  The output end of the horizontal transfer path 103 is branched into a first branch transfer path 104 and a second branch transfer path 105 by a charge distribution unit (charge branching unit) 120. The first branch transfer path 104 and the second branch transfer path 105 have the same configuration (embedded channel and transfer electrode) as the horizontal transfer path 103, and the output end of the first branch transfer path 104 has A first output amplifier 106 is provided that outputs a voltage value signal corresponding to the amount of signal charge transferred to the output terminal. The output terminal of the second branch transfer path 105 is transferred to the output terminal. A second output amplifier 107 is provided for outputting a voltage value signal corresponding to the amount of signal charge.

  The first branch transfer path 104 and the second branch transfer path 105 are transfer pulses φ4 generated by dividing the transfer pulses φ1 and φ2 for driving the horizontal transfer path 103 by 1/2, respectively, by the image sensor driving unit 20. , Φ5 to drive two phases.

  The output bifurcated solid-state imaging device 100 of this embodiment includes a line memory 108 along the horizontal transfer path 103 at the boundary between the end of each vertical transfer path 102 and the horizontal transfer path 103.

  The line memory 108 temporarily stores the signal charge received from each vertical transfer path 102 and controls the timing to output to the horizontal transfer path 103 as described in, for example, JP-A-2002-112119, It is used for performing horizontal pixel addition of signal charges. Pixel addition is performed when shooting a moving image with a digital camera, that is, when outputting a reduced image, and pixel addition is not performed when a still image is captured.

  In the present embodiment, the output bifurcated solid-state imaging device provided with the line memory 108 is illustrated. However, the signal charges transferred through the vertical transfer path 102 are directly received by the horizontal transfer path 103 without using the line memory 108. It may be configured to pass. Further, although the color solid-state imaging device 100 having the honeycomb pixel arrangement has been described, a solid-state imaging device in which photodiodes are arranged in a square lattice shape and color filters are arranged in a Bayer array may be used.

  Although the terms “vertical” and “horizontal” have been used, this means “one direction” along the surface of the semiconductor substrate and “a direction substantially perpendicular to the one direction”.

  The horizontal transfer path 103 of this embodiment is formed so that the width of the buried channel gradually becomes narrower as it approaches the charge distribution unit 120, and the width of the transfer electrode (length in the vertical direction) is also shortened accordingly. Is formed. In the illustrated example, the width is narrowed to about ½ so that the upper side 103 d gradually approaches the bottom side 103 c of the horizontal transfer path 103.

  FIG. 3 is a schematic view illustrating the order of signal charges transferred from the horizontal transfer path 103 to the branch transfer paths 104 and 105. “R” is a signal charge read from a photodiode mounted with a red filter, and “G” is a signal charge read from a photodiode mounted with a green filter. Signal charges are transferred along the horizontal transfer path 103 in the order of R, G, R, G,.

  When the R signal charge first flows into the charge distributing unit 120 at the timing T = 2 by the transfer of the signal charge, the R signal charge flows into the second branch transfer path 105 through the charge distributing unit 120. Become.

  At the next timing T = 3, this time, the G signal charge is transferred to the adjacent position of the charge distributing unit 120. When the G signal charge flows into the charge distributing unit 120 at T = 4, the G signal charge is The charge distribution unit 120 passes through and flows into the first branch transfer path 104.

  Similarly, in the illustrated embodiment, all the R signal charges flow into the second branch transfer path 105 side, and the voltage value signal is read out by the output amplifier 107 provided at the output of the second branch transfer path 105. All the G signal charges flow into the first branch transfer path 104 side, and the voltage value signal is read out by the output amplifier 106 provided at the output of the first branch transfer path 104.

  As described above, in the output bifurcated solid-state imaging device 100 of the present embodiment, the voltage value signal is output as a signal corresponding to the charge amount of the signal charge transferred at half the driving frequency of the horizontal transfer path 103. Therefore, even if the horizontal transfer path 103 is driven at a high speed, the waveform of the output data is not disturbed.

  As shown in FIG. 3, in this embodiment, the number of transfer electrodes provided in the second branch transfer path 105 is increased by one compared to the number of transfer electrodes provided in the first branch transfer path 104. This is because the first branch transfer path 104 and the second branch transfer path 105 are driven by the same transfer pulse HPφ3, φ4, and the voltage value signal of the G signal charge transferred to the output terminal by the first branch transfer path 104. This is because the amplifier 107 can read out the voltage value signal of the R signal charge transferred to the output terminal by the second branch transfer path 105 at the same time.

  As a result, only one system is required for phase adjustment when the analog image data read from the solid-state imaging device is correlated double-sampled by the analog front end.

  In addition, the signal charge after reading the voltage value signal can be discarded to the reset drain simultaneously using the same reset signal in the first branch transfer path 104 and the second branch transfer path. It should be noted that when the signal charge is discarded to the reset drain, it is preferable that the signal charge exists in a narrow range. For this reason, the widths of the output end portions of the first branch transfer path 104 and the second branch transfer path 105 are reduced.

  In the pixel array shown in FIG. 2, after the signal charges arranged in the order of R, G, R, G,... Are distributed to the branch transfer paths 104 and 105 in the horizontal transfer path 103, the signal charges are output to the horizontal transfer path 103. , B, G, B, G,..., Signal charges are transferred from the line memory 108 in this order. Even in this case, the B signal charge is distributed to the branch transfer path 105 and the G signal charge is distributed to the branch transfer path 104 in the same manner as described above, and the G signal charge is transferred and output using the branch transfer path 104 in any state. It is good to make a configuration.

  Thereby, the voltage value signal of the G signal charge is always read by the output amplifier 106, and the voltage value signals of the R signal charge and the B signal charge are always read by the output amplifier 107, and white balance correction is performed. The gain difference between the amplifiers 106 and 107 is absorbed.

  FIG. 4 is a schematic surface view showing details of the charge distribution unit 120 at the connection between the horizontal transfer path 103 and the branch transfer paths 104 and 105 shown in FIG. The horizontal transfer path 103 includes a buried channel and a set of a first layer electrode 103a and a second layer electrode 103b repeatedly stacked on the buried channel, and one of the set of the first layer electrode 103a and the second layer electrode 103b. A transfer pulse φ1 is applied to every other set, and a transfer pulse φ2 having a phase opposite to that of the transfer pulse φ1 is applied to the remaining every other set.

  The branch transfer path 104 and the branch transfer path 105 are separated by an element isolation band 110 that is a high concentration region of p-type impurities, and charge distribution is performed between the horizontal transfer path 103 and the branch transfer paths 104 and 105. A portion 120 is provided. The charge distribution unit 120 includes a distribution electrode (branch electrode) including a first layer electrode 120a and a second layer electrode 120b stacked on a narrowly formed buried channel.

  The first layer electrode 120a has a shape of a flat isosceles triangle in a top view, but the first transfer electrode films 104a, 104b, 105a, 105b of the branch transfer paths 104, 105 enter the charge distribution unit 120. Therefore, only the thin protrusion-like electrode film 120c is left between the apex portion of the first layer electrode film 120a and the element isolation band 110, and the whole has a funnel shape.

  That is, the main body vertex position of the first layer electrode film 120a is provided apart from the element isolation band 110 by the length of the protruding electrode film 120c. The width X of the electrode film 120c is narrower than the width Y (the length in the transfer direction) Y of the transfer electrode films 104b and 105b.

  The second layer electrode film 120b is provided in a strip shape via an insulating layer at the bottom of the first layer electrode film 120a. A fixed voltage φ3 is applied to the first layer electrode 120a (including 120c) and the second layer electrode 120b from the image sensor driving unit 20.

  The first branch transfer path 104 is connected to one side of the oblique side of the distribution electrode 120a, and the second branch transfer path 105 is connected to the other side of the distribution electrode 120a. In the horizontal transfer path 103 of this embodiment, the channel width is gradually reduced only on one side, that is, one side (branch transfer path 104 side) in the vicinity of the charge distribution unit 120 side.

  Each of the first branch transfer path 104 and the second branch transfer path 105 is composed of a buried channel and a set of first layer electrode and second layer electrode repeatedly stacked thereon, as in the horizontal charge transfer path 103. The transfer pulse φ4 is applied to every other set of the first layer electrode and the second layer electrode, and the transfer pulse φ5 having a phase opposite to that of the transfer pulse φ4 is applied to every other set. It is configured.

  When the transfer pulse φ5 is applied to the first layer electrode 104a and the second layer electrode 104b that are closest to the distribution electrode 120a of the first branch transfer path 104, the distribution electrode 120a of the second branch transfer path 105 is applied to the distribution electrode 120a. A transfer pulse φ4 is applied to the first layer electrode 105a and the second layer electrode 105b that are adjacent to each other.

  FIG. 5 is a schematic cross-sectional view along A1-A2-A3-A4 in FIG. 4 and a diagram showing a potential profile thereof. An n-type buried channel 131 is formed in the p-well layer 130 formed on the surface portion of the n-type semiconductor substrate. The first layer electrode films 103a, 120a, and 105a (104a in the case of the first branch transfer path) are stacked on the surface of the semiconductor substrate, and an insulating layer is provided between the first layer electrode films. The second layer electrode films 103b, 120b, and 105b (104b) are laminated.

The n-type buried channel 131 includes an N-doped region I constituting the horizontal charge transfer path 103, an N-doped region II constituting the charge distribution unit 120, and an N-doped region III constituting the branch transfer paths 104 and 105. The impurity concentration is divided into
Region I <Region II <Region III
It has become.

  For this reason, in the potential profile, the potentials of the branch transfer paths 104 and 105 after branching are formed deeper than the potential of the horizontal charge transfer path 103 before branching, and the potential at the branching portion 120 is an intermediate position.

  Therefore, by applying a fixed voltage (for example, ground voltage) to the electrodes 120a and 120b of the branching portion 120 and fixing the potential, the signal charge transferred through the horizontal charge transfer path 103 flows into the branching portion 120 and remains as it is. Then, it flows into the branch transfer path 104 or 105.

  Since the applied voltages φ4 and φ5 of the branch transfer paths 104 and 105 are opposite in phase, their potentials rise and fall alternately. As a result, the signal charge flows into the branch transfer path that is deeper than the potential of the branch section 120.

  In the present embodiment, as shown in FIG. 5, since the potential in the charge branching portion 120 has a gradient in the entire region, the signal charge flowing into the charge branching portion 120 from the horizontal charge transfer path 103 is in the charge branching portion 120. Without stopping, it flows into the branch transfer path 104 or 105 as it is.

  FIG. 6 is a diagram illustrating a result of calculating the potential distribution in the charge branching portion in which the sorting electrode 120a has a funnel shape as in the present embodiment. In the vicinity of position A2 in FIG. 4, since it is the end portion of the base of the flat triangle shape, the potential is shallower than position A3 due to the short channel effect, and the potential becomes deeper from position A2 toward position A3. A slope is formed.

  In addition, since the apex position of the flat triangular shape is away from the element isolation band (p-type high concentration impurity region) 110, it is suppressed from being pulled shallow by the potential of the element isolation band 110, and a deep state is maintained. The

  Further, since the width of the protruding electrode film 120c is narrowed, the potential of the protruding portion becomes shallow due to the short channel effect. Accordingly, the apex position of the flat triangle shape in the sorting electrode film 120a becomes the region having the deepest potential, and the charge is transferred to the branch transfer paths 104 and 105 through a path that flows through this area.

  As a result, when the signal charge that has flowed from the horizontal charge transfer path 103 into the charge distribution section 120 is flowed into the branch transfer path 105, even the signal charge that has flowed into the location A2 far from the charge distribution section 120 is between A2 and A3. Due to the potential gradient, the flow smoothly flows into the branch transfer path 105 and is not left behind in the charge branch portion 120.

  As described above, according to the present embodiment, the distribution electrode of the charge branching portion 120 is separated from the flat triangular main body portion and the barrier electrode of the two branch transfer paths protruding from the apex position of the main body portion. And a width of the protruding portion is made narrower than the width of the barrier electrode (the length that the transfer charge crosses), and the length of the protruding portion is separated from the element isolation region that separates the two branch transfer paths. The flat triangle shape is sufficiently separated from each other so that the potential of the element isolation region does not reach the potential of the vertex position, so the potential formed under the distribution electrode can have a gradient overall. It becomes.

  As a result, in the output two-branch solid-state imaging device of the present embodiment, the signal charge of the horizontal charge transfer path can be distributed to the two branch transfer paths without leaving any good, and high quality without color mixing or the like. An image can be taken.

  The solid-state imaging device according to the present invention is useful when mounted on an imaging device such as a digital camera capable of capturing a high-definition image.

It is a block block diagram of the digital camera carrying the solid-state image sensor which concerns on one Embodiment of this invention. It is a surface schematic diagram of the solid-state image sensor shown in FIG. FIG. 3 is a diagram for explaining a state of charge transfer distribution in the output two-branch horizontal charge transfer path shown in FIG. 2. It is a detailed surface schematic diagram around the charge distribution part of the solid-state imaging device shown in FIG. FIG. 5 is a schematic cross-sectional view and a potential diagram along A1-A2-A3-A4 in FIG. It is a figure which shows the result of having calculated the potential distribution in the shape of the charge distribution part shown in FIG. It is a principal part top schematic diagram of the output 2 branch type horizontal charge transfer path provided with the conventional T-shaped charge distribution part. It is a principal part top schematic diagram of the output 2 branch type | mold horizontal charge transfer path provided with the conventional triangular charge distribution part. It is a figure which shows the result of having calculated the electric potential distribution in the triangular charge distribution part shown in FIG.

Explanation of symbols

100 Solid-state image sensor 103 Horizontal charge transfer path 104, 105 Branch transfer path 106, 107 Output amplifier 103a Storage electrode film (first layer electrode film) of horizontal charge transfer path
103b Barrier electrode film (second layer electrode film) of horizontal charge transfer path
104a, 105a Storage electrode film (first layer electrode film) of branch transfer path
104b, 105b Barrier electrode film (second layer electrode film) of branch transfer path
120 Charge distribution part (charge branching part)
120a Distribution electrode (branch electrode) film (first layer electrode film) of charge distribution unit
120b Barrier electrode film (second layer electrode film) of charge distribution unit
120c Projection portions φ1 and φ2 of the distribution electrode film of the charge distribution section Transfer pulse φ3 of the horizontal charge transfer path Fixed voltage φ4 and φ5 applied to the charge distribution section Transfer pulse of the branch transfer path

Claims (8)

  A horizontal charge transfer path; a charge branching unit that alternately distributes signal charges transferred along the horizontal charge transfer path in two directions; and two branch transfer paths provided corresponding to the two directions. In the output two-branch solid-state imaging device, the shape of the sorting electrode film provided in the charge branching portion is such that the bottom portion is adjacent to the end of the horizontal charge transfer path and one of the two oblique sides is one of the branch transfer paths. And the other hypotenuse is formed in a triangular shape adjacent to the other branch transfer path, and a projecting electrode film separating the two branch transfer paths from the apex facing the base of the triangle is extended. An output bifurcated solid-state imaging device.   2. The output bifurcated solid-state imaging device according to claim 1, wherein the protruding electrode film extends to an element separation band that separates the two branch transfer paths.   The width of the protruding electrode film is narrower than the width of the barrier electrode film (length in the direction in which charges cross) of the two branch transfer paths separated by the electrode film. Item 3. The output bifurcated solid-state imaging device according to Item 2.   The output bifurcated solid-state imaging device according to any one of claims 1 to 3, wherein the triangular shape is a flat isosceles triangle.   When the charge branching portion performs charge distribution, a fixed voltage is applied to the distribution electrode, and the signal charge flowing from the horizontal charge transfer path flows into one of the branch transfer paths without accumulating. The output bifurcated solid-state imaging device according to any one of claims 1 to 4.   The signal charge is an electron, and the horizontal charge transfer path, the charge branching portion, and the buried channel of the branch transfer path are each an n-type impurity layer, and the impurity concentration of the n-type impurity layer is equal to the horizontal charge transfer path < 6. The output two-branch solid-state imaging device according to claim 5, wherein the darkening is in the order of charge branching portion <branch transfer path.   7. The width of the horizontal charge transfer path (length in a direction perpendicular to the charge transfer direction) becomes narrower as it approaches the charge branching section. Output bifurcated solid-state image sensor.   8. The output bifurcated solid-state imaging device according to claim 1; drive means for driving the output bifurcated solid-state imaging device; and read from the output bifurcated solid-state imaging device. An image pickup apparatus comprising: signal processing means for processing a picked-up image signal.

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