Solid-state imaging element, imaging device, and method for manufacturing solid-state imaging element

• US 10,910,504 B2
• Filed: 09/28/2016
• Issued: 02/02/2021
• Est. Priority Date: 12/07/2015
• Status: Active Grant

• Current Assignee: Sony Semiconductor Solutions Corporation (Sony Group Corp.)
• Original Assignee: Sony Semiconductor Solutions Corporation (Sony Group Corp.)
• Inventors: Yokogawa, Sozo
• Primary Examiner(s): Fan, Bo
• Application Number:
  US15/777,853
• Publication Number:
  US 20180351013A1
• Time in Patent Office: 1,588 Days
• Field of Search: 257432, 257229, 438 29
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02B 5/22 Absorbing filters G02B5/201 - G02B5/208 take precedence
• CPC Class Codes: G02B 5/26 Reflecting filters G02B5/28 takes precedence
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: H01L 27/14 including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation radiation-sensitive components structurally associated with one or more electric light sources only H01L31/14; couplings of light guides with optoelectronic elements G02B6/42
• CPC Class Codes: H01L 27/146 Imager structures
• CPC Class Codes: H01L 27/1462 Coatings
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14629 Reflectors
• CPC Class Codes: H01L 27/1463 Pixel isolation structures
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 25/704 Pixels specially adapted for focusing, e.g. phase difference pixel sets

Abstract

[Object] To propose a solid-state imaging element, an imaging device, and a method for manufacturing a solid-state imaging element that are capable of providing a pixel with polarization sensitivity while suppressing the reduction in sensitivity to non-polarized incident light. [Solution] A solid-state imaging element according to the present disclosure includes: a light receiving element included in a plurality of pixels; and a groove section provided on surfaces of at least some of the pixels in the light receiving element and extended along a prescribed direction. Two or more directions including at least mutually orthogonal two directions exist as a direction in which the groove section is extended.

Claims

1. A solid-state imaging element, comprising:

a plurality of pixels;

a light receiving element in a pixel of the plurality of pixels;

a plurality of groove sections on a surface of the light receiving element, wherein

the plurality of groove sections extends along an extending direction, and

the extending direction is one of a plurality of directions that includes at least two mutually orthogonal directions;

a flattening film on the plurality of groove sections, wherein the flattening film flattens the surface of the light receiving element;

a wavelength selection filter on the flattening film, wherein the wavelength selection filter is in contact with the flattening film; and

a dielectric multiple-layer film between a groove section of the plurality of groove sections and the flattening film, wherein

a shape of the dielectric multiple-layer film is similar to a shape of the groove section,

the dielectric multiple-layer film comprises at least two dielectric layers with mutually different refractive indices, and

each dielectric layer of the at least two dielectric layers has an optical thickness of approximately λ

/4N_λ

,

where λ

represents a center wavelength of light transmitted through the wavelength selection filter and N_λ

represents a refractive index of a corresponding dielectric layer of the at least two dielectric layers.

2. The solid-state imaging element according to claim 1, wherein, as the groove section, at least

a first groove section provided on surfaces of some of the plurality of pixels in the light receiving element and extended along a first direction, and

a second groove section provided on surfaces of some of the plurality of pixels in the light receiving element and extended along a second direction orthogonal to the first direction are provided.

3. The solid-state imaging element according to claim 1, wherein a cross-sectional shape of the groove section of the plurality of groove sections is one of a V-like shape or a tapered shape.

4. The solid-state imaging element according to claim 1, wherein

the plurality of groove sections is on a light receiving surface of each pixel of the plurality of pixels, and

each of an interval between mutually adjacent groove sections of the plurality of groove sections and a width of the groove section of the plurality groove sections is in a range of 100 nm to 1000 nm.

5. The solid-state imaging element according to claim 1, wherein

the plurality of groove sections is on a light receiving surface of each pixel of the plurality of pixels, and

an interval between mutually adjacent groove sections of the plurality of groove sections and a width of the groove section of the plurality groove sections are each a size of one over an integer of a pixel size.

6. The solid-state imaging element according to claim 1, wherein the pixel is configured to exhibit one of a specific reflection characteristic or a specific absorption characteristic for incident light polarized in a specific direction.

7. The solid-state imaging element according to claim 1, further comprising a specific dielectric layer on a surface of the groove section of the plurality of groove sections, wherein the specific dielectric layer has a high permittivity (high k) material as a main component.

8. The solid-state imaging element according to claim 1, further comprising a trench structure between mutually adjacent pixels of the plurality of pixels.

9. The solid-state imaging element according to claim 8, wherein the trench structure is a metal trench structure that comprises, as a main component, a metal configured to one of reflect or absorb visible light and near-infrared light.

10. The solid-state imaging element according to claim 9, wherein the metal comprises one of tungsten, titanium, copper, aluminum, or an alloy of these.

11. The solid-state imaging element according to claim 8, wherein a main component of the trench structure is a dielectric material.

12. The solid-state imaging element according to claim 11, wherein

the dielectric material is one of a specific material or a high-permittivity (high-k) material, and

the specific material is configured to one of reflect or absorb visible light and near-infrared light.

13. The solid-state imaging element according to claim 12, wherein the dielectric material comprises one of SiO₂ or SiN.

14. The solid-state imaging element according to claim 12, wherein the high-permittivity (high-k) material comprises one of HfO, Ta₂O₅, or TiO₂.

15. The solid-state imaging element according to claim 1, wherein a direction in which the groove section is extended is substantially parallel to a direction making an angle of 0 degrees, 45 degrees, 90 degrees, or 135 degrees with one of orthogonal axes prescribing a placement position of the pixel.

16. The solid-state imaging element according to claim 1, wherein

the light receiving element comprises single-crystal silicon, and

at least a part of the groove section of the plurality of groove sections comprises an Si(111) plane.

17. An imaging device, comprising:

a solid-state imaging element including;

a plurality of pixels;

a light receiving element in a pixel of the plurality of pixels;

a plurality of groove sections on a surface of the light receiving element, wherein

the plurality of groove sections extends along an extending direction, and

the extending direction is one of a plurality of directions that includes at least two mutually orthogonal directions;

a flattening film on the plurality of groove sections, wherein the flattening film flattens the surface of the light receiving element;

a wavelength selection filter on the flattening film, wherein the wavelength selection filter is in contact with the flattening film; and

a dielectric multiple-layer film between a groove section of the plurality of groove sections and the flattening film, wherein

a shape of the dielectric multiple-layer film is similar to a shape of the groove section,

the dielectric multiple-layer film comprises at least two dielectric layers with mutually different refractive indices, and

each dielectric layer of the at least two dielectric layers has an optical thickness of approximately λ

/4N_λ

,

where λ

represents a center wavelength of first light transmitted through the wavelength selection filter and N_λ

represents a refractive index of a corresponding dielectric layer of the at least two dielectric layers; and

an optical system configured to guide second light to the solid-state imaging element.

18. The imaging device according to claim 17, wherein a retardation film is provided on some of the plurality of pixels in the solid-state imaging element.

19. The imaging device according to claim 17, further comprising:

two or more of the solid-state imaging elements,

wherein directions in which the plurality of groove sections in the solid-state imaging elements are extended are the same as each other, and

a retardation film is provided on an optical path between at least one of the solid-state imaging elements and the optical system.

20. The imaging device according to claim 17, further comprising:

two or more of the solid-state imaging elements,

wherein a direction in which the groove section in one of the solid-state imaging elements is extended and a direction in which the groove section in another of the solid-state imaging elements is extended are different.

21. The imaging device according to claim 17, further comprising a signal processing section configured to calculate, based on intensity information of the second light, at least one of an orientation angle and a degree of polarization of polarized light incident on the solid-state imaging element.