Solid-state image sensor
A solid-state image sensor includes pixels, each of which is provided with a light receiving portion, a charge storage portion, a gate electrode, a first trench formed in a region between the light receiving portion and the charge storage portion, a first insulating film provided in the first trench, a transmitting portion, and a light-shielding film covering the charge storage portion, the transmitting portion, and the gate electrode. In a plan view, a distance from an end of the light-shielding film through the transmitting portion to the charge storage portion in a direction from the light receiving portion toward the charge storage portion is longer than a distance from the end of the light-shielding film through the first trench to the charge storage portion.
1. A solid-state image sensor comprising an image region in which a plurality pixels are arranged, wherein
each of the pixels includes:
a light receiving portion provided in a semiconductor substrate and generating a charge by photoelectric conversion;
a charge storage portion provided in the semiconductor substrate and storing the charge generated in the light receiving portion;
a gate electrode provided on the charge storage portion and transferring the charge generated in the light receiving portion to the charge storage portion;
a first trench formed in a region of the semiconductor substrate between the light receiving portion and the charge storage portion;
a first insulating film provided in the first trench;
a second trench formed in a region of the semiconductor substrate between the light receiving portions of adjacent ones of the pixels;
a second insulating film provided in the second trench;
a transmitting portion provided at an end of a boundary between the light receiving portion and the charge storage portion so as to be in contact with the first insulating film, and serving as a transfer path of the charge from the light receiving portion to the charge storage portion; and
a light-shielding film covering the charge storage portion, the transmitting portion, and the gate electrode, and
in a plan view, a distance from an end of the light-shielding film through the transmitting portion to the charge storage portion in a direction from the light receiving portion toward the charge storage portion is longer than a distance from the end of the light-shielding film through the first trench to the charge storage portion.
2. The solid-state image sensor of claim 1 , wherein
a portion of the light receiving portion, which is in contact with the transmitting portion, protrudes beyond another portion facing the charge storage portion.
3. The solid-state image sensor of claim 2 , wherein
a portion of the light-shielding film which is provided in an upper portion of the transmitting portion protrudes toward the light receiving portion as compared to a portion provided above the first trench.
4. The solid-state image sensor of claim 3 , wherein
a portion of the charge storage portion which is in contact with the transmitting portion has a higher n-type impurity concentration than the other portion of the charge storage portion.
5. The solid-state image sensor of claim 3 , wherein
the first and second insulating films have a lower refractive index than the semiconductor substrate.
6. The solid-state image sensor of claim 3 , wherein
the charge storage portion is an n-type impurity region formed on a first p-type impurity region, and
the transmitting portion is a second p-type impurity region having a lower p-type impurity concentration than the first p-type impurity region.
7. The solid-state image sensor of claim 2 , wherein
a portion of the charge storage portion which is in contact with the transmitting portion has a higher n-type impurity concentration than the other portion of the charge storage portion.
8. The solid-state image sensor of claim 2 , wherein
the first and second insulating films have a lower refractive index than the semiconductor substrate.
9. The solid-state image sensor of claim 2 , wherein
the charge storage portion is an n-type impurity region formed on a first p-type impurity region, and
the transmitting portion is a second p-type impurity region having a lower p-type impurity concentration than the first p-type impurity region.
10. The solid-state image sensor of claim 1 , wherein
a portion of the light-shielding film which is provided in an upper portion of the transmitting portion protrudes toward the light receiving portion as compared to a portion provided above the first trench.
11. The solid-state image sensor of claim 10 , wherein
a portion of the charge storage portion which is in contact with the transmitting portion has a higher n-type impurity concentration than the other portion of the charge storage portion.
12. The solid-state image sensor of claim 10 , wherein
the first and second insulating films have a lower refractive index than the semiconductor substrate.
13. The solid-state image sensor of claim 10 , wherein
the charge storage portion is an n-type impurity region formed on a first p-type impurity region, and
the transmitting portion is a second p-type impurity region having a lower p-type impurity concentration than the first p-type impurity region.
14. The solid-state image sensor of claim 1 , wherein
a portion of the charge storage portion which is in contact with the transmitting portion has a higher n-type impurity concentration than the other portion of the charge storage portion.
15. The solid-state image sensor of claim 1 , wherein
the first and second insulating films have a lower refractive index than the semiconductor substrate.
16. The solid-state image sensor of claim 1 , wherein
the charge storage portion is an n-type impurity region formed on a first p-type impurity region, and
the transmitting portion is a second p-type impurity region having a lower p-type impurity concentration than the first p-type impurity region.