Solid-state imaging device and electronic apparatus
Provided is a solid-state imaging device and an electronic apparatus capable of achieving both of a high dynamic range operation and an auto focus operation in a pixel configuration in which a plurality of unit pixels includes two or more subpixels. The solid-state imaging device includes a first pixel separation region that separates a plurality of unit pixels including two or more subpixels, a second pixel separation region that separates each of the plurality of unit pixels separated by the first pixel separation region and an overflow region that causes signal charges accumulated in the subpixels to overflow to at least one of adjacent subpixels, in which the overflow region is formed between a first subpixel and a second subpixel.
1. A solid-state imaging device, comprising:
a first pixel separation region that separates a plurality of unit pixels, wherein each unit pixel of the plurality of unit pixels includes at least two subpixels;
a second pixel separation region that separates each unit pixel of the plurality of unit pixels into the at least two subpixels;
an overflow region configured to control a plurality of signal charges in each subpixel of the at least two subpixels to overflow to at least one adjacent subpixel of the at least two subpixels; and
a first P-type region along the first pixel separation region in a cross-sectional view of the solid-state imaging device, wherein
the overflow region is between the first pixel separation region and the second pixel separation region, and
an impurity concentration of the overflow region is lower than an average impurity concentration of the first P-type region.
2. The solid-state imaging device according to claim 1 , further comprising a second P-type region, wherein
the first P-type region is in a depth direction inside the first pixel separation region,
the second P-type region is in the depth direction around the second pixel separation region,
the first pixel separation region, the overflow region, and the second pixel separation region are included in a cross section,
in the cross section, a region of a unit pixel of the plurality of unit pixels not separated by the second pixel separation region is cut along an incident direction of light, and
the overflow region includes at least one of:
a third P-type region whose impurity concentration is lower than the average impurity concentration of the first P-type region, or
a fourth P-type region whose impurity concentration is lower than an average impurity concentration of the second P-type region.
3. The solid-state imaging device according to claim 1 , further comprising:
a second P-type region; and
an N-type region between the first P-type region and the second P-type region, wherein
the first P-type region is in a depth direction inside the first pixel separation region,
the second P-type region is in the depth direction around the second pixel separation region,
the first pixel separation region, the overflow region, and the second pixel separation region are included in a cross section,
in the cross section, a region of a unit pixel of the plurality of unit pixels not separated by the second pixel separation region is cut along an incident direction of light, and
the overflow region includes at least one of:
a third P-type region whose impurity concentration is lower than the average impurity concentration of the first P-type region,
a fourth P-type region whose impurity concentration is lower than an average impurity concentration of the second P-type region, or
a fifth N-type region between the third P-type region and the fourth P-type region.
4. The solid-state imaging device according to claim 1 , further comprising:
a transistor in a first region of the solid-state imaging device, wherein the transistor is configured to control the overflow; and
an N-type region that includes a second region, wherein
the plurality of signal charges is accumulated in the N-type region,
an impurity concentration in the N-type region is highest in the second region of the N-type region,
the first P-type region is in a depth direction inside the first pixel separation region,
the overflow region is between a first inner side of the first pixel separation region and a second inner side of the first pixel separation region,
the first inner side is opposite to the second inner side in a cross section,
in the cross section, a region of a unit pixel of the plurality of unit pixels not separated by the second pixel separation region is cut along an incident direction of light, and
the overflow region has a depth between the first region that includes the transistor and the second region in which an impurity concentration is the highest.
5. The solid-state imaging device according to claim 1 , wherein
the second pixel separation region separates each unit pixel of the plurality of unit pixels into a plurality of subpixels of 2×2, and
the plurality of subpixels includes the at least two subpixels.
6. The solid-state imaging device according to claim 1 , wherein the second pixel separation region has a cross shape.
7. The solid-state imaging device according to claim 6 , wherein
the first pixel separation region is in a threshold distance from the second pixel separation region in a specific region of the solid-state imaging device, and
the specific region includes the overflow region.
8. The solid-state imaging device according to claim 6 , wherein the first pixel separation region has a width one of same or different from the second pixel separation region having the cross shape.
9. The solid-state imaging device according to claim 6 , wherein at least a part of the second pixel separation region having the cross shape is connected to the first pixel separation region.
10. The solid-state imaging device according to claim 1 , further comprising a transfer gate configured to execute a voltage control to cause the plurality of signal charges to overflow.
11. The solid-state imaging device according to claim 10 , further comprising a power supply configured to supply voltages of at least three values to the transfer gate.
12. The solid-state imaging device according to claim 10 , further comprising a boosting circuit configured to boost and step down a voltage of the voltages supplied to the transfer gate.
13. The solid-state imaging device according to claim 1 , further comprising:
a silicon substrate;
a light receiving surface configured to receive light; and
a photoelectric conversion element on the silicon substrate, wherein the photoelectric conversion element is configured to accumulate the plurality of signal charges, wherein
the second pixel separation region penetrates from the light receiving surface to the silicon substrate.
14. A solid-state imaging device, comprising:
a first pixel separation region that separates a plurality of unit pixels, wherein each unit pixel of the plurality of unit pixels includes at least two subpixels;
a second pixel separation region that separates each unit pixel of the plurality of unit pixels into the at least two subpixels;
a first light condensing portion that covers entirety of a unit pixel of the plurality of unit pixels, wherein the first light condensing portion is a lens; and
a plurality of second light condensing portions, wherein each second light condensing portion covers a respective subpixel of the at least two subpixels, wherein a second light condensing portion of the plurality of second light condensing portions includes:
a light shielding portion above the first pixel separation region and the second pixel separation region;
a light transmitting layer above a subpixel of the at least two subpixels, wherein
the light transmitting layer is surrounded by the light shielding portion, and
the light transmitting layer includes a material having a higher refractive index than the light shielding portion; and
an intermediate layer between the first light condensing portion and the light transmitting layer, wherein
the intermediate layer includes a material that has a refractive index higher than the first light condensing portion and lower than the light transmitting layer.
15. The solid-state imaging device according to claim 14 , wherein the plurality of second light condensing portions are lenses.
16. The solid-state imaging device according to claim 14 , wherein
the light shielding portion includes a material having a lower refractive index than a metal, and
the light shielding portion above the second pixel separation region includes a material having a lower refractive index than the light transmitting layer.
17. The solid-state imaging device according to claim 14 , further comprising a color filter between a subpixel of the at least two subpixels and the second light condensing portion.
18. An electronic apparatus, comprising:
a solid-state imaging device that includes:
a first pixel separation region that separates a plurality of unit pixels, wherein each unit pixel of the plurality of unit pixels includes at least two subpixels;
a second pixel separation region that separates each unit pixel of the plurality of unit pixels into the at least two subpixels;
an overflow region configured to control a plurality of signal charges in each subpixel of the at least two subpixels to overflow to at least one adjacent subpixel of the at least two subpixels; and
a first P-type region along the first pixel separation region in a cross-sectional view of the solid-state imaging device, wherein
the overflow region is between the first pixel separation region and the second pixel separation region, and
an impurity concentration of the overflow region is lower than an average impurity concentration of the first P-type region.