Solid-state image pickup device
A solid-state image pickup device 1 according to the present invention includes a semiconductor substrate 2 on which a pixel 20 composed of a photodiode 3 and a transistor is formed. The transistor comprising the pixel 20 is formed on the surface of the semiconductor substrate, a pn junction portion formed between high concentration regions of the photodiode 3 is provided within the semiconductor substrate 2 and a part of the pn junction portion of the photodiode 3 is extended to a lower portion of the transistor formed on the surface of the semiconductor substrate 2 . According to the present invention, there is provided a solid-state image pickup device in which a pixel size can be microminiaturized without lowering a saturated electric charge amount (Qs) and sensitivity.
1. A solid-state image pickup device comprising:
a photodiode in a semiconductor substrate, a groove portion is an indentation in semiconductor substrate that extends from a surface of the semiconductor substrate to the photodiode;
a floating diffusion region of the semiconductor substrate at the surface of the semiconductor substrate, a portion of the semiconductor substrate separates the photodiode from the floating diffusion region;
a gate insulating film on an inner wall of the groove portion, the photodiode and the floating diffusion region touch the gate insulating film; and
a columnar gate electrode in the groove portion, the gate insulating film touches the columnar gate electrode.
2. The solid-state image pickup device according to claim 1 , wherein the floating diffusion region is of a conductivity type opposite to the semiconductor substrate.
3. The solid-state image pickup device according to claim 1 , wherein the semiconductor substrate is of a first conductivity type and the floating diffusion region is of a second conductivity type.
4. The solid-state image pickup device according to claim 3 , wherein the second conductivity type is opposite to the first conductivity type.
5. The solid-state image pickup device according to claim 3 , wherein the first conductivity type is P-type.
6. The solid-state image pickup device according to claim 1 , further comprising:
a channel region of the semiconductor substrate at the surface of the semiconductor substrate.
7. The solid-state image pickup device according to claim 6 , wherein the channel region is between a transistor region of the semiconductor substrate and the floating diffusion region.
8. The solid-state image pickup device according to claim 6 , wherein the channel region and the transistor region are of a same conductivity type.
9. The solid-state image pickup device according to claim 6 , further comprising:
a gate electrode in an interlayer insulator.
10. The solid-state image pickup device according to claim 9 , wherein the channel region is between the photodiode and the gate electrode.
11. The solid-state image pickup device according to claim 9 , wherein the surface of the semiconductor substrate is between the interlayer insulator and the channel region.
12. The solid-state image pickup device according to claim 9 , wherein the columnar gate electrode extends into the interlayer insulator.
13. The solid-state image pickup device according to claim 1 , wherein the portion of the semiconductor substrate is between the photodiode and the floating diffusion region.
14. The solid-state image pickup device according to claim 1 , wherein the gate insulating film is between the columnar gate electrode and the floating diffusion region.
15. The solid-state image pickup device according to claim 1 , wherein the gate insulating film is between the columnar gate electrode and the photodiode.
16. The solid-state image pickup device according to claim 1 , wherein the photodiode is configured to convert incident light into a signal electric charge.