Back side illumination image sensors and electronic device including the same
In some example embodiments, a back side illumination (BSI) image sensor may include a pixel configured to generate electrical signals in response to light incident on a back side of a substrate. In some example embodiments, the pixel includes, a photodiode, a device isolation film adjacent to the photodiode, a dark current suppression layer above the photodiode, a light shield grid above the photodiode and including an opening area of 1 to 15% of an area of the pixel, a light shielding filter layer above the light shield grid, a planarization layer above the light shielding filter layer, a lens above the planarization layer, and/or an anti-reflective film between the photodiode and the lens.
1. A back side illumination image sensor comprising:
a pixel configured to generate electrical signal in response to light incident on a back side of a substrate comprising:
a photodiode,
a device isolation film adjacent to the photodiode,
a dark current suppression layer above the photodiode,
a light shield grid above the photodiode and including an opening area of 1 to 15% of an area of the pixel,
a light shielding filter layer above the light shield grid,
a planarization layer above the light shielding filter layer,
a lens above the planarization layer, and
an anti-reflective film between the photodiode and the lens.
2. The back side illumination image sensor of claim 1 , wherein the device isolation film and the dark current suppression layer include a plurality of laminated layers, each layer having a negative fixed charge.
3. The back side illumination image sensor of claim 1 , wherein the device isolation film penetrates the back side of the substrate with a depth between 1 μm and 5 μm.
4. The back side illumination image sensor of claim 2 , wherein each of the plurality of laminated layers of the device isolation film and the dark current suppression layer includes at least one material selected from a group including aluminum oxide (AlO), tantalum oxide (TaO), hafnium oxide (HfO), zirconium oxide (ZrO), and lanthanum oxide (LaO).
5. The back side illumination image sensor of claim 1 , wherein the opening area of the light shield grid is aligned with a central portion of the photodiode.
6. The back side illumination image sensor of claim 1 , wherein the light shield grid is configured to receive a voltage within a range of 0 V to −2 V.
7. The back side illumination image sensor of claim 1 , wherein the anti-reflective film is under or above the light shield grid.
8. The back side illumination image sensor of claim 1 , wherein the anti-reflective film is between the light shield grid and the planarization layer.
9. The back side illumination image sensor of claim 1 , wherein the anti-reflective film is between the planarization layer and the lens.
10. The back side illumination image sensor of claim 1 , wherein the anti-reflective film is under or above the light shielding filter layer.
11. The back side illumination image sensor of claim 10 , wherein
the anti-reflective film includes a plurality of sub-films, at least two of the sub-films having a refractive index different from each other, and
the at least two have refractive indices within a range of 1.4 to 2.6.
12. The back side illumination image sensor of claim 11 , wherein the plurality of sub-films comprises:
a first sub-film having a first refractive index, and
a second sub-film having a second refractive index that is greater than the first refractive index.
13. The back side illumination image sensor of claim 11 , wherein
the plurality of sub-films comprises:
a first sub-film having a first refractive index, and
a second sub-film having a second refractive index that is smaller than the first refractive index, and
the second sub-film is laminated on the first sub-film.
14. The back side illumination image sensor of claim 1 , wherein the anti-reflective film includes a plurality of alternately laminated sub-films, wherein the plurality of alternately laminated sub-films includes a first sub-film having a first refractive index and a second sub-film having a second refractive index that is greater than the first refractive index.
15. A back side illumination image sensor comprising:
a plurality of pixels configured to generate electrical signals in response to light incident on a back side of a substrate, wherein each pixel of the plurality of pixels comprises:
a photodiode,
a dark current suppression layer above the photodiode,
a light shield grid above the photodiode and including an opening area aligned to a central portion of the photodiode,
a planarization layer above the light shield grid,
a lens above the planarization layer, and
an anti-reflective film between the photodiode and the lens; and
a plurality of readout circuits configured to read the electrical signals of the plurality of pixels.
16. The back side illumination image sensor of claim 15 , wherein the dark current suppression layer includes a plurality of laminated layers, wherein each layer of the plurality of laminated layers has a negative fixed charge.
17. The back side illumination image sensor of claim 15 , wherein the light shield grid is configured to receive a voltage within a range of 0 V to −2 V.