Solid-state imaging element and electronic device
The present disclosure relates to a solid-state imaging element and an electronic device capable of increasing the capacitance of a charge holding unit. The solid-state imaging element includes a pixel including a photodiode, an FD that accumulates charges generated in the photodiode, and a charge holding unit that is connected in parallel with the FD. The charge holding unit includes a wiring capacitance formed by parallel running of a first wiring connected to a first potential and a second wiring connected to a second potential different from the first potential. The present disclosure can be applied to a solid-state imaging element that performs global shutter type imaging.
1. A solid-state imaging element, comprising:
a pixel, including:
a photodiode;
a floating diffusion that accumulates charges generated in the photodiode; and
a charge holding unit,
wherein the charge holding unit includes a wiring capacitance formed by a first wiring connected to a first potential and a second wiring connected to a second potential different from the first potential,
wherein, in a plan view, at least a part of the first wiring and at least a part of the second wiring are surrounded by a third wiring that is connected to a fixed potential.
2. The solid-state imaging element according to claim 1 , wherein a bent portion of the first wiring and the second wiring is formed in any of an L-shape, a T-shape, a U-shape, and a cross shape.
3. The solid-state imaging element according to claim 2 , wherein the first wiring and the second wiring are formed in one or more wiring layers, and
wherein a part of the first wiring and the second wiring is formed directly above the photodiode.
4. The solid-state imaging element according to claim 3 , wherein a part of the first wiring and the second wiring is formed in the wiring layer of a first layer directly above a substrate.
5. The solid-state imaging element according to claim 4 , wherein a part of the first wiring and the second wiring is formed so that a line width and a distance between the first wiring and the second wiring are narrower than a wavelength to be captured.
6. The solid-state imaging element according to claim 3 , wherein
the second wiring is formed as at least one of an FD wiring connected to the FD, a fixed potential line, and a control line of a pixel transistor.
7. The solid-state imaging element according to claim 6 , wherein
a potential of the fixed potential line includes GND.
8. The solid-state imaging element according to claim 6 , wherein
the pixel transistor includes a transfer transistor.
9. The solid-state imaging element according to claim 6 , wherein the first wiring runs in parallel with the floating diffusion wiring to form a coupling capacitance with the floating diffusion.
10. The solid-state imaging element according to claim 9 , wherein the first wiring and the floating diffusion wiring are formed in a region surrounded by the fixed potential line or the control line.
11. The solid-state imaging element according to claim 10 , wherein the solid-state imaging element includes a plurality of pixels, and
wherein the first wiring and the second wiring are formed in a same wiring layout in all the pixels.
12. The solid-state imaging element according to claim 11 , wherein the first wiring and the second wiring are in a same wiring layer as one another and form the wiring capacitance in that same wiring layer.
13. The solid-state imaging element according to claim 11 , wherein the first wiring and the second wiring are in different wiring layers from one another and form the wiring capacitance between the different wiring layers.
14. The solid-state imaging element according to claim 2 , wherein the first wiring and the second wiring are in a same wiring layer as one another and form the wiring capacitance in a same wiring layer and between different wiring layers.
15. The solid-state imaging element according to claim 11 ,
wherein the first wiring and the second wiring are in different wiring layers,
wherein extensions of the first wiring extend in a first direction,
wherein extensions of the second wiring extend in a second direction, and
wherein the first direction is perpendicular to the second direction.
16. The solid-state imaging element according to claim 11 , wherein a film having a high dielectric constant is used as an insulating film between the first wiring and the second wiring.
17. The solid-state imaging element according to claim 2 , wherein a diffusion layer is provided in a substrate, wherein the substrate is connected to the first wiring, and wherein the diffusion layer provided in the substrate has a larger area than another diffusion layer forming the pixel transistor.
18. A solid-state imaging element, comprising:
a pixel, including:
a photodiode;
a floating diffusion that accumulates charges generated in the photodiode; and
a charge holding unit that is connected in parallel with the floating diffusion,
wherein the charge holding unit includes a wiring capacitance formed by parallel running of a first wiring connected to a first potential and a second wiring connected to a second potential different from the first potential,
wherein the first wiring and the second wiring each have an extending portion extending in a first direction and a bent portion extending in a second direction,
wherein the bent portion of the first wiring and the second wiring is formed in any of an L-shape, a T-shape, a U-shape, and a cross shape,
wherein the first wiring and the second wiring are formed in one or more wiring layers,
wherein a part of the first wiring and the second wiring is formed directly above the photodiode,
wherein a part of the first wiring and the second wiring is formed in the wiring layer of a first layer directly above a substrate,
wherein a part of the first wiring and the second wiring is formed so that a line width and a distance between the first wiring and the second wiring are narrower than a wavelength to be captured, and
wherein each of a part of the first wiring and the second wiring is formed in a comb shape facing each other in a same wiring layer.
19. An electronic device, comprising:
a solid-state imaging element, including:
a pixel, including:
a photodiode;
a floating diffusion that accumulates charges generated in the photodiode; and
a charge holding unit,
wherein the charge holding unit includes a wiring capacitance formed by a first wiring connected to a first potential and a second wiring connected to a second potential different from the first potential,
wherein, in a plan view, at least a part of the first wiring and at least a part of the second wiring are surrounded by a third wiring that is connected to a fixed potential.