Solid-state image pickup device, method of manufacturing solid-state image pickup device, and electronic apparatus
There is provided a solid-state image pickup device including: a semiconductor substrate ( 21 ); a photodiode ( 11 A, 11 B) formed in the semiconductor substrate; a transistor ( 10 ) having a gate electrode ( 14 ) part or all of which is embedded in the semiconductor substrate, the transistor being configured to read a signal electric charge from the photodiode via the gate electrode; and an electric charge transfer layer ( 13 ) provided between the gate electrode and the photodiode.
1. A solid-state image pickup device, comprising:
a semiconductor substrate;
a photoelectric conversion layer formed in the semiconductor substrate;
a transistor having a gate electrode, at least a portion of the gate electrode being embedded in the semiconductor substrate; and
an electric charge transfer layer provided adjacent to a bottom surface of the gate electrode;
wherein,
the photoelectric conversion layer is formed directly over, in a depth direction of the semiconductor substrate, at least part of the gate electrode that is embedded, and
the transistor is configured to read a signal electric charge from the photoelectric conversion layer which is formed directly over the at least part of the gate electrode via the gate electrode and the electric charge transfer layer.
2. The solid-state image pickup device according to claim 1 , wherein the photoelectric conversion layer is one of a plurality of photoelectric conversion layers that are positioned in the depth direction of the semiconductor substrate.
3. The solid-state image pickup device according to claim 1 , wherein
the photoelectric conversion layer has a first conductivity type, and the electric charge transfer layer is an impurity diffusion layer of the first conductivity type connected to a portion of the photoelectric conversion layer.
4. The solid-state image pickup device according to claim 2 , wherein
the photoelectric conversion layer has a first conductivity type, and the electric charge transfer layer is an impurity diffusion layer of the first conductivity type connected to a portion of the photoelectric conversion layer.
5. The solid-state image pickup device according to claim 1 , wherein
the electric charge transfer layer serves as a transfer path of signal electric charges and serves as an additional photoelectric conversion layer.
6. The solid-state image pickup device according to claim 2 , wherein
the electric charge transfer layer serves as a transfer path of signal electric charges and serves as an additional photoelectric conversion layer.
7. The solid-state image pickup device according to claim 4 , wherein
the electric charge transfer layer serves as a transfer path of signal electric charges and serves as an additional photoelectric conversion layer.
8. The solid-state image pickup device according to claim 1 , wherein the gate electrode fills a concave section in the semiconductor substrate.
9. The solid-state image pickup device according to claim 2 , wherein the gate electrode fills a concave section in the semiconductor substrate.
10. The solid-state image pickup device according to claim 4 , wherein the gate electrode fills a concave section in the semiconductor substrate.
11. The solid-state image pickup device according to claim 1 , wherein the gate electrode fills a concave section in the semiconductor substrate and wherein the electric charge transfer layer serves as a transfer path of signal electric charges to the gate electrode.
12. The solid-state image pickup device according to claim 2 , wherein the gate electrode fills a concave section in the semiconductor substrate and wherein the electric charge transfer layer serves as a transfer path of signal electric charges to the gate electrode.
13. The solid-state image pickup device according to claim 4 , wherein the gate electrode fills a concave section in the semiconductor substrate and wherein the electric charge transfer layer serves as a transfer path of signal electric charges to the gate electrode.
14. The solid-state image pickup device according to claim 8 , further comprising:
a dark current suppression layer of a second conductivity type that is in contact with the electric charge transfer layer and a bottom face of the concave section.
15. The solid-state image pickup device according to claim 9 , further comprising:
a dark current suppression layer of a second conductivity type that is in contact with the electric charge transfer layer and a bottom face of the concave section.
16. The solid-state image pickup device according to claim 10 , further comprising:
a dark current suppression layer of a second conductivity type that is in contact with the electric charge transfer layer and a bottom face of the concave section.
17. The solid-state image pickup device according to claim 8 , wherein the electric charge transfer layer is adjacent to a bottom face of the concave section and a portion of side faces of the concave section.
18. The solid-state image pickup device according to claim 9 , wherein the electric charge transfer layer is adjacent to a bottom face of the concave section and a portion of side faces of the concave section.
19. The solid-state image pickup device according to claim 10 , wherein the electric charge transfer layer is adjacent to a bottom face of the concave section and a portion of side faces of the concave section.
20. The solid-state image pickup device according to claim 1 , further comprising:
a floating diffusion adjacent to a first end of the gate electrode, wherein the first end is opposite from the bottom surface.
21. The solid-state image pickup device according to claim 20 , wherein the electric charge transfer layer is a part of a transfer path of signal electric charges from the photoelectric conversion layer to the gate electrode and the floating diffusion.
22. The solid-state image pickup device according to claim 1 ,
wherein the plurality of photoelectric conversion layers comprise the photoelectric conversion layer and a secondary photoelectric conversion layer, the secondary photoelectric conversion layer being located adjacent to the gate electrode, and a length of the photoelectric conversion layer is greater than a length of the secondary photoelectric conversion layer, and
wherein the length of the photoelectric conversion layer and the length of the secondary photoelectric conversion layer are measured in a direction opposite from the depth direction of the semiconductor substrate.
23. The solid-state image pickup device according to claim 1 ,
wherein the plurality of photoelectric conversion layers comprise the photoelectric conversion layer and a secondary photoelectric conversion layer, the secondary photoelectric conversion layer receives light that has passed through the photoelectric conversion layer.
24. The solid-state image pickup device according to claim 23 ,
wherein a length of the photoelectric conversion layer is greater than a length of the secondary photoelectric conversion layer, and the length of the photoelectric conversion layer and the length of the secondary of the photoelectric conversion layer are measured in a direction opposite from the depth direction of the semiconductor substrate.
25. The solid-state image pickup device according to claim 8 , wherein the electric charge transfer layer is self-aligned adjacent to a bottom face of the concave section.
26. The solid-state image pickup device according to claim 8 , wherein the electric charge transfer layer has a desired thickness based on a predetermined set dose amount in ion implantation and injection energy.
27. The solid-state image pickup device according to claim 25 , wherein the electric charge transfer layer has a desired thickness based on a predetermined set dose amount in ion implantation and injection energy.
28. The solid-state image pickup device according to claim 25 , wherein defects that occur caused by a potential dip are reduced when transferring signal electric charges through the electric charge transfer layer based on a location of the electric charge transfer layer in relation to the bottom face.
29. The solid-state image pickup device according to claim 28 , wherein a position that is a reference for the bottom face is set in a shallower position than a depth of the concave section in advance of forming the concave section.
30. An electronic apparatus, comprising:
a solid-state image pickup device, comprising:
a semiconductor substrate;
a photoelectric conversion layer formed in the semiconductor substrate;
a transistor having a gate electrode, at least a portion of the gate electrode being embedded in the semiconductor substrate; and
an electric charge transfer layer provided adjacent to a bottom surface of the gate electrode;
wherein,
the photoelectric conversion layer is formed directly over, in a depth direction of the semiconductor substrate, at least part of the gate electrode that is embedded, and
the transistor is configured to read a signal electric charge from the photoelectric conversion layer which is formed directly over the at least part of the gate electrode via the gate electrode and the electric charge transfer layer.