Photoelectric conversion device having embedded recess regions arranged in light-receiving surface
A device includes a plurality of photoelectric conversion regions, an interlayer insulating film arranged on the plurality of photoelectric conversion regions, a protective insulating film that is arranged in contact with the interlayer insulating film and has a refractive index different from that of the interlayer insulating film, recesses arranged in a light-receiving surface of each of the plurality of photoelectric conversion regions, and embedded regions embedded in the recesses. When a wavelength of incident light to each of the plurality of photoelectric conversion regions is denoted by λ and a refractive index of the embedded regions is denoted by n, a depth d of the recesses is represented by an expression d≧λ/4n.
1. A device comprising:
a plurality of photoelectric conversion regions;
an interlayer insulating film arranged on the plurality of photoelectric conversion regions;
a protective insulating film that is arranged in contact with the interlayer insulating film and has a refractive index different from that of the interlayer insulating film;
recesses arranged in a light-receiving surface of each of the plurality of photoelectric conversion regions; and
embedded regions embedded in the recesses,
wherein, when a wavelength of incident light to each of the plurality of photoelectric conversion regions is denoted by λ and a refractive index of the embedded regions is denoted by n, a depth d of the recesses is represented by an expression d≧λ/4n, and
wherein the plurality of photoelectric conversion regions includes a semiconductor region for collecting signal carriers, wherein a contact hole is provided above the semiconductor region for collecting signal carriers, and a metal electrode is filled in the contact hole,
the semiconductor region for collecting signal carriers is electrically connected to a readout circuit through the metal electrode, and
the semiconductor region for collecting signal carriers is not provided with recesses.
2. The device according to claim 1 , further comprising:
an anti-reflection film that is arranged on the light-receiving surface and surfaces of the recesses of each of the plurality of photoelectric conversion regions and that has a refractive index higher than that of the interlayer insulating film.
3. The device according to claim 1 , wherein the embedded regions include a first insulating film and a second insulating film that is arranged in contact with the first insulating film and has a refractive index higher than that of the first insulating film.
4. The device according to claim 1 , wherein the recesses and the embedded regions are formed by a local oxidation of silicon (LOCOS) method.
5. The device according to claim 1 , wherein each of the plurality of photoelectric conversion regions is configured by including a first semiconductor region and a second semiconductor region that forms a PN junction together with the first semiconductor region,
wherein the second semiconductor region is connected to a readout circuit, and
wherein the recesses are surrounded by the first semiconductor region.
6. The device according to claim 1 , wherein the recesses are arranged in a repetitive pattern with a certain pitch.
7. The device according to claim 1 , wherein the depth d of the recesses is in a range of λ/4n≦d≦λ.
8. The device according to claim 1 , further comprising:
a color filter corresponding to each of the plurality of photoelectric conversion regions,
wherein the wavelength of the incident light is a peak wavelength of light that passes through the color filter.
9. The device according to claim 8 , wherein the wavelength of the incident light is a peak wavelength of light that passes through a blue color filter.
10. A device for visible light comprising:
a plurality of photoelectric conversion regions arranged on a silicon substrate;
a silicon oxide film arranged on the plurality of photoelectric conversion regions;
a protective insulating film that is arranged in contact with the silicon oxide film and has a refractive index different from that of the silicon oxide film;
recesses arranged in a light-receiving surface of each of the plurality of photoelectric conversion regions; and
silicon oxide embedded regions embedded in the recesses, wherein a depth d of the recesses is in a range of 0.06≦d≦0.15 μm, and
wherein the plurality of photoelectric conversion regions includes a semiconductor region for collecting signal carriers, wherein a contact hole is provided above the semiconductor region for collecting signal carriers, and a metal electrode is filled in the contact hole,
the semiconductor region for collecting signal carriers is electrically connected to a readout circuit through the metal electrode, and the semiconductor region for collecting signal carriers is not provided with recesses.
11. The device according to claim 10 , further comprising:
an anti-reflection film that is arranged on the light-receiving surface and surfaces of the recesses of each of the plurality of photoelectric conversion regions and that has a refractive index higher than that of the silicon oxide film.
12. The device according to claim 10 , wherein the silicon oxide embedded regions include a first insulating film and a second insulating film that is arranged in contact with the first insulating film and has a refractive index higher than that of the first insulating film.
13. The device according to claim 10 , wherein the recesses and the silicon oxide embedded regions are formed by a local oxidation of silicon (LOCOS) method.
14. The device according to claim 10 , wherein each of the plurality of photoelectric conversion regions is configured by including a first semiconductor region and a second semiconductor region that forms a PN junction together with the first semiconductor region,
wherein the second semiconductor region is connected to a readout circuit, and
wherein the recesses are surrounded by the first semiconductor region.
15. The device according to claim 10 , wherein the recesses are arranged in a repetitive pattern with a certain pitch.
16. The device according to claim 10 , wherein the depth d of the recesses is in a range of λ/4n≦d≦λ, where λ is a wavelength of incident light to each of the plurality of photoelectric conversion regions and n is a refractive index of the silicon oxide embedded region.
17. The device according to claim 10 , further comprising:
a color filter corresponding to each of the plurality of photoelectric conversion regions,
wherein a wavelength of the incident light is a peak wavelength of light that passes through the color filter.
18. The device according to claim 17 , wherein the wavelength of the incident light is a peak wavelength of light that passes through a blue color filter.