Photoelectric conversion device
A photoelectric conversion device includes a pixel including an amplifier transistor generating a signal according to charge generated in a photoelectric conversion unit and a select transistor controlling an output of the signal, and an output line outputting the signal from the pixel. The photoelectric conversion unit includes a first semiconductor region for accumulating charge, the select transistor includes a second semiconductor region to which the output line is connected, and the pixel further includes a third semiconductor region being capable of discharging charge. The second semiconductor region is adjacent to the first semiconductor region via a first element isolation structure, and is adjacent to the third semiconductor region via a second element isolation structure. A shortest distance between the first and second semiconductor regions via the first element isolation structure is greater than a shortest distance between the second and third semiconductor regions via the second element isolation structure.
1 . A photoelectric conversion device comprising:
a pixel provided on a semiconductor substrate and including a photoelectric conversion unit, a floating diffusion to which charge generated in the photoelectric conversion unit is transferred, an amplifier transistor that generates a signal according to a voltage of the floating diffusion, and a select transistor that controls an output of the signal; and
an output line to which the signal from the pixel is output,
wherein the photoelectric conversion unit includes a first semiconductor region of a first conductivity type for storing charge generated by photoelectric conversion,
wherein the select transistor includes a second semiconductor region of the first conductivity type forming a node to which the output line is connected,
wherein the pixel further includes a third semiconductor region of the first conductivity type configured to discharge charge,
wherein the second semiconductor region is adjacent to the first semiconductor region with a first element isolation structure interposed therebetween, and is adjacent to the third semiconductor region with a second element isolation structure interposed therebetween, and
wherein a shortest distance between the first semiconductor region and the second semiconductor region via the first element isolation structure is greater than a shortest distance between the second semiconductor region and the third semiconductor region via the second element isolation structure.
2 . The photoelectric conversion device according to claim 1 , wherein the third semiconductor region is connected to a node to which a power supply voltage is supplied.
3 . The photoelectric conversion device according to claim 2 , wherein the third semiconductor region is a main node of the amplifier transistor.
4 . The photoelectric conversion device according to claim 2 ,
wherein the pixel further includes a reset transistor configured to reset a voltage of the floating diffusion, and
wherein the third semiconductor region is a main node of the reset transistor.
5 . The photoelectric conversion device according to claim 1 , wherein the first element isolation structure is formed of an insulator structure.
6 . The photoelectric conversion device according to claim 5 , wherein the second element isolation structure is formed of an insulator structure.
7 . The photoelectric conversion device according to claim 6 , wherein the insulator structure constituting the first element isolation structure is provided deeper in the semiconductor substrate than the insulator structure constituting the second element isolation structure.
8 . The photoelectric conversion device according to claim 5 , wherein the second element isolation structure is comprised of a fourth semiconductor region of a second conductivity type different from the first conductivity type.
9 . The photoelectric conversion device according to claim 1 , wherein the first element isolation structure is comprised of a fifth semiconductor region of a second conductivity type different from the first conductivity type.
10 . The photoelectric conversion device according to claim 9 , wherein the second element isolation structure is comprised of a sixth semiconductor region of the second conductivity type.
11 . The photoelectric conversion device according to claim 10 , wherein an impurity concentration of the fifth semiconductor region is higher than an impurity concentration of the sixth semiconductor region.
12 . The photoelectric conversion device according to claim 1 , wherein the third semiconductor region is formed deeper in the semiconductor substrate than the first semiconductor region.
13 . The photoelectric conversion device according to claim 1 ,
wherein the select transistor comprises a plurality of select transistors and the output line comprises a plurality of output lines provided corresponding to the plurality of select transistors, and
wherein the third semiconductor region comprises a plurality of third semiconductor regions provided corresponding to the second semiconductor region of each of the plurality of select transistors.
14 . The photoelectric conversion device according to claim 1 , wherein the pixel comprises a plurality of pixels each connected to the output line.
15 . A system comprising:
the photoelectric conversion device according to claim 1 ; and
a signal processing device configured to process a signal output from the photoelectric conversion device.
16 . A movable object comprising:
the photoelectric conversion device according to claim 1 ;
an acquisition unit configured to acquire distance information to an object from a parallax image based on a signal from the photoelectric conversion device; and
a control unit configured to control the movable object based on the distance information.
17 . Equipment comprising:
the photoelectric conversion device according to claim 1 , and
at least one of
an optical device corresponding to the photoelectric conversion device,
a control device configured to control the photoelectric conversion device,
a processing device configured to process a signal output from the photoelectric conversion device,
a mechanical device that is controlled based on information obtained by the photoelectric conversion device,
a display device configured to display information obtained by the photoelectric conversion device, and
a storage device configured to store information obtained by the photoelectric conversion device.
18 . The photoelectric conversion device according to claim 1 ,
wherein the charge is a first polarity, and
wherein a potential barrier for the charge of the first polarity of the first element isolation structure between the first semiconductor region and the second semiconductor region is higher than a potential barrier for the charge of the first polarity of the second element isolation structure between the second semiconductor region and the third semiconductor region.