Solid-state image pickup device
A solid-state image pickup device includes a semiconductor substrate within which a pixel comprised of a photodiode and a transistor is formed. The transistor is formed at a surface of the semiconductor substrate, a pn junction portion formed between high concentration regions of the photodiode is provided within the semiconductor substrate and a part of the pn junction portion of the photodiode is extended to a lower portion of the transistor formed at the surface of the semiconductor substrate.
1. A method for operating a solid-state image pickup device, the method comprising:
introducing light through a back of substrate into a photodiode, said photodiode converting said light into a signal;
transferring said signal along a channel portion to a source-drain region, said photodiode being between said channel portion and said back of the substrate,
wherein a gate insulating film is between a gate electrode and said channel portion, said gate electrode and said gate insulating film being within a groove,
wherein said photodiode is composed of a region of a first conductivity and a region of a second conductivity, said region of the first conductivity being between said region the second conductivity and said back of the substrate.
2. The method according to claim 1 , wherein said channel portion is between said source-drain region and said photodiode.
3. The method according to claim 1 , wherein said groove extends into said substrate from a surface of the substrate.
4. The method according to claim 3 , wherein said photodiode is between said back of the substrate and said surface of the substrate.
5. The method according to claim 1 , wherein said substrate is of said second conductivity.
6. The method according to claim 1 , wherein said source-drain region is of said first conductivity.
7. The method according to claim 1 , wherein said channel portion is of said second conductivity.
8. The method according to claim 1 , wherein said first conductivity has a conductivity opposite to said second conductivity.
9. The method according to claim 1 , wherein said first conductivity is n-type, said second conductivity being p-type.
10. The method according to claim 1 , wherein said region of the first conductivity includes high and low impurity concentration regions, said high impurity concentration region of the first conductivity being between said low impurity concentration region of the first conductivity and said region of the second conductivity.
11. The method according to claim 10 , wherein said low impurity concentration region of the first conductivity has an impurity concentration lower than said high impurity concentration region of the first conductivity.
12. The method according to claim 1 , wherein said region of the second conductivity includes high and low impurity concentration regions, said low impurity concentration region of the second conductivity being between said high impurity concentration region of the second conductivity and said groove.
13. The method according to claim 12 , wherein said low impurity concentration region of the second conductivity has an impurity concentration lower than said high impurity concentration region of the second conductivity.
14. The method according to claim 12 , wherein said region of the second conductivity includes another low impurity concentration region, said another low impurity concentration region of the second conductivity has an impurity concentration lower than said high impurity concentration region of the second conductivity.
15. The method according to claim 14 , wherein said groove extends to said another low impurity concentration region.
16. The method according to claim 15 , wherein said low impurity concentration region of the second conductivity is in contact with said another low impurity concentration region.
17. The method according to claim 1 , further comprising:
transferring said signal along another channel portion from said source-drain region to another source-drain region, said another channel portion being between said source-drain region and said another source-drain region.