Photodetection device and electronic apparatus
The present disclosure relates to a photodetection device and an electronic apparatus that allow for reducing surface reflection from an on-chip microlens and suppressing deterioration of image quality. Provided is a photodetection device including: a plurality of pixels that have photoelectric conversion units; on-chip microlenses that are formed in such a way as to correspond to the individual pixels; and an antireflection film that is formed on a surface of the on-chip microlens, in which the antireflection film is constituted by a stacking of: a first inorganic film that is formed by a metal oxide film; and a second inorganic film that is formed on a surface of the first inorganic film and has a lower refractive index than the first inorganic film. The present disclosure can be applied to, for example, a CMOS solid-state imaging device.
1 . A photodetection device, comprising:
a plurality of pixels that have photoelectric conversion units;
a plurality of circular, continuously formed on-chip microlenses, wherein each on-chip microlens of the plurality of microlenses is formed in such a way as to correspond to one individual pixel of the plurality of pixels; and
an antireflection film that is formed on a surface of each on-chip microlens distal from the plurality of pixels, wherein the antireflection film is constituted by a stacking of:
a first inorganic film; and
a second inorganic film that is formed to have a fine uneven shape on a surface of the first inorganic film and has a lower refractive index than the first inorganic film.
2 . The photodetection device according to claim 1 , wherein the first inorganic film is a tantalum oxide film, a niobium oxide film, a titanium oxide film, or a hafnium oxide film.
3 . The photodetection device according to claim 2 , wherein the second inorganic film is a silicon dioxide film or a silicon oxycarbide film.
4 . The photodetection device according to claim 1 , wherein the first inorganic film has a refractive index of 1.8 or more, and the second inorganic film has a refractive index of 1.55 or less.
5 . The photodetection device according to claim 1 , wherein a film thickness of the first inorganic film is less or equal to a film thickness of the second inorganic film all along an arcuate portion of each on-chip microlens.
6 . The photodetection device according to claim 5 , wherein the antireflection film has a film thickness of less than or equal to 200 nanometers (nm).
7 . The photodetection device according to claim 1 , wherein the first inorganic film is disposed between each on-chip microlens and the second inorganic film.
8 . The photodetection device according to claim 7 , wherein the first inorganic film is an adhesion film to bring each on-chip microlens and the second inorganic film into close contact with each other and is formed as a low temperature oxidation silicon dioxide film having a refractive index of less than or equal to 1.55.
9 . The photodetection device according to claim 8 , wherein the second inorganic film is a structural film formed as an aluminum oxide film.
10 . The photodetection device according to claim 9 , wherein a film thickness of at least one of the first inorganic film and the second inorganic film disposed on an arcuate portion of each on-chip microlens is greatest at a center of each on-chip microlens and radially tapers to a lesser thickness at a circumference of each on-chip microlens.
11 . The photodetection device according to claim 10 , wherein the first inorganic film has a film thickness of from 5 nm to 1000 nm.
12 . The photodetection device according to claim 10 , wherein a maximum film thickness from a highest protrusion of the fine uneven shape of the second inorganic film to an interface with the first inorganic film is approximately 270 nm.
13 . The photodetection device according to claim 1 , wherein a film thickness of the antireflection film disposed on an arcuate portion of each on-chip microlens is greatest at a center of each on-chip microlens and radially tapers to a lesser thickness at a circumference of each on-chip microlens.
14 . The photodetection device according to claim 1 , wherein a radius of curvature of a surface of the second inorganic film distal from the plurality of pixels is different than a radius of curvature of a surface of the first inorganic film distal from the plurality of pixels.
15 . The photodetection device according to claim 1 , wherein a radius of curvature of a surface of the first inorganic film distal from the distal from the plurality of pixels is different than a radius of curvature of a surface of each on-chip microlens distal from the distal from the plurality of pixels.
16 . The photodetection device according to claim 1 , wherein a radius of curvature of a surface of the second inorganic film distal from the distal from the plurality of pixels is different than a radius of curvature of a surface of each on-chip microlens distal from the distal from the plurality of pixels.
17 . The photodetection device according to claim 1 , further comprising a plurality flat portions separating the arcuate portion of each on-chip microlens, wherein the antireflection film is further formed on a surface of each flat portion of the plurality of flat portions.
18 . The photodetection device according to claim 1 , wherein a film thickness of the first inorganic film and a film thickness of the second inorganic film disposed on an arcuate portion of each on-chip microlens is greatest at a center of each on-chip microlens and radially tapers to a lesser thickness at a circumference of each on-chip microlens.
19 . A photodetection device, comprising:
a plurality of pixels that have photoelectric conversion units;
a plurality of circular, continuously formed on-chip microlenses, wherein each on-chip microlens of the plurality of microlens is formed in such a way as to correspond to one individual pixel of the plurality of pixels; and
an antireflection film that is formed on a surface of each on-chip microlens distal from the plurality of pixels, wherein the antireflection film is constituted by a stacking of:
a first inorganic film; and
a second inorganic film that is a structural film formed on a surface of the first inorganic film and has a lower refractive index than the first inorganic film, and
wherein the second inorganic is formed by processing a surface of a film to be processed having a predetermined refractive index into a fine uneven shape.
20 . The photodetection device according to claim 19 , wherein the first inorganic film is an adhesion film disposed between each on-chip microlens and the second inorganic film to bring the on-chip microlens and the second inorganic film into close contact with each other and is formed as a low temperature oxidation silicon dioxide film having a refractive index of less than or equal to 1.55.
21 . The photodetection device according to claim 20 , wherein the film to be processed is an aluminum oxide film, and wherein the predetermined refractive index is 1.6.
22 . The photodetection device according to claim 21 , wherein as processed, the second inorganic film has a refractive index of 1.3.
23 . An electronic apparatus on which a photodetection device is mounted, the photodetection device including:
a plurality of pixels that have photoelectric conversion units;
a plurality of circular, continuously formed on-chip microlenses, wherein each on-chip microlens of the plurality of microlenses is formed in such a way as to correspond to one individual pixel of the plurality of pixels; and
an antireflection film that is formed on a surface of each on-chip microlens distal from the plurality of pixels, wherein the antireflection film is constituted by a stacking of:
a first inorganic film that is formed as a low temperature oxidation silicon dioxide film; and
a second inorganic film that is formed as a fine uneven shape of aluminum oxide on a surface of the first inorganic film and has a lower refractive index than the first inorganic film.