SOLID-STATE IMAGE SENSOR

• US 20110068251A1
• Filed: 08/06/2010
• Published: 03/24/2011
• Est. Priority Date: 08/08/2009
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: NARUI, Tadashi
• Granted Patent: US 9,337,231 B2
• Time in Patent Office: Days
• US Class Current: 250/208.1
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14641 Electronic components shared by two or more pixel-elements, e.g. one amplifier shared by two pixel elements
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements

Abstract

A solid-state image sensor includes: four or more photoelectric conversion units having spectral sensitivity characteristics different from one another; an amplifier unit disposed in correspondence to each group of photoelectric conversion units among N groups (N represents an integer less than a quantity of the four or more photoelectric conversion units and equal to or greater than one), the four or more photoelectric conversion units being divided into the N groups; and transfer units, each disposed in correspondence to one of the four or more photoelectric conversion units, which transfer a signal generated at the photoelectric conversion unit to the amplifier unit disposed for the group to which the photoelectric conversion unit belongs.

Claims

1. A solid-state image sensor, comprising:

four or more photoelectric conversion units having spectral sensitivity characteristics different from one another;

an amplifier unit disposed in correspondence to each group of photoelectric conversion units among N groups (N represents an integer less than a quantity of the four or more photoelectric conversion units and equal to or greater than one), the four or more photoelectric conversion units being divided into the N groups; and

transfer units, each disposed in correspondence to one of the four or more photoelectric conversion units, which transfer a signal generated at the photoelectric conversion unit to the amplifier unit disposed for the group to which the photoelectric conversion unit belongs.

2. A solid-state image sensor according to claim 1, wherein:

a plurality of photoelectric conversion units belonging to a single group have successive spectral sensitivity characteristics.

3. A solid-state image sensor according to claim 1, further comprising:

a floating capacitor unit disposed at an input portion of the amplifier unit installed in correspondence to each group.

4. A solid-state image sensor according to claim 1, wherein:

charge storage layers, each constituting one of a plurality of photoelectric conversion units belonging to a single group, are disposed in alignment with one another along a direction in which light enters.

5. A solid-state image sensor according to claim 1, wherein:

color filters having different spectral transmittance characteristics in correspondence to the individual groups are disposed on a light-entry side of the photoelectric conversion units.

6. A solid-state image sensor according to claim 4, wherein:

the quantity of the four or more photoelectric conversion units is six, N is equal to three and a quantity of photoelectric conversion units belonging to each group is two.

7. A solid-state image sensor according to claim 1, further comprising:

a control unit that enables selective execution of operation at the photoelectric conversion units in a first operation mode or a second operation mode by controlling the transfer units, wherein;

in the first operation mode, signals corresponding to signals generated in a plurality of photoelectric conversion units are separately output from the amplifier unit, the plurality of photoelectric conversion units among the four or more photoelectric conversion units belonging to a given group; and

in the second operation mode, a signal corresponding to a signal representing a sum of signals generated in the plurality of photoelectric conversion units is output from the amplifier unit, the plurality of photoelectric conversion units among the four or more photoelectric conversion units belonging to the given group.

8. A solid-state image sensor according to claim 1, further comprising:

a control unit that enables selective execution of operation at the photoelectric conversion units in a first operation mode or a second operation mode by controlling the transfer units, wherein;

in the first operation mode, signals corresponding to individual signals generated in a plurality of photoelectric conversion units, are output separately from the amplifier unit, the plurality of photoelectric conversion units belonging to a given group; and

in the second operation mode, a signal corresponding to a signal generated in a photoelectric conversion unit among the plurality of photoelectric conversion units is separately output from the amplifier unit and a signal corresponding to a signal representing a sum of signals generated in two or more photoelectric conversion units among the plurality of photoelectric conversion units is also output from the amplifier unit, the plurality of photoelectric conversion units belonging to the given group.

11. A solid-state image sensor according to claim 6, wherein:

the three groups each include a first photoelectric conversion unit with a charge storage layer thereof disposed on a light-entry side and a second photoelectric conversion unit with a charge storage layer thereof disposed on a side opposite from the light-entry side;

the three first photoelectric conversion units in the three groups are formed so as to satisfy a first condition and the three second photoelectric conversion units in the three groups are formed so as to satisfy a second condition; and

the first condition stipulates that the charge storage layers each constituting one of the three first photoelectric conversion units assume positions with a uniform depth measured from a semiconductor surface on the light-entry side and the second condition stipulates that the charge storage layers each constituting one of the three second photoelectric conversion units assume positions with a uniform depth measured from the semiconductor surface on the light-entry side.

12. A solid-state image sensor according to claim 6, wherein:

the three groups each include a first photoelectric conversion unit with a charge storage layer thereof disposed on a light-entry side and a second photoelectric conversion unit with a charge storage layer thereof disposed on a side opposite from the light-entry side;

the three first photoelectric conversion units in the three groups and the three second photoelectric conversion units in the three groups are formed so that at least one of a first condition and a second condition is not satisfied; and

the first condition stipulates that the charge storage layers each constituting one of the three first photoelectric conversion units assume positions with a uniform depth measured from a semiconductor surface on the light-entry side and the second condition stipulates that the charge storage layers each constituting one of the three second photoelectric conversion units assume positions with a uniform depth measured from the semiconductor surface on the light-entry side.

15. A solid-state image sensor according to claim 6, wherein:

the N groups are made up with a first group, a second group and a third group;

the color filters disposed in conjunction with the first group are red color filters;

the color filters disposed in conjunction with the second group are green color filters;

the color filters disposed in conjunction with the third group are blue color filters;

a charge storage layer constituting one of the photoelectric conversion units belonging to the first group is formed at a depth within a range of 0.4 to 0.6 μ

m measured from a semiconductor surface located on a light-entry side;

a charge storage layer constituting another photoelectric conversion unit belonging to the first group is formed at a depth within a range of 2.1 to 2.3 μ

m measured from the semiconductor surface on the light-entry side;

a charge storage layer constituting one of the photoelectric conversion units belonging to the second group is formed at a depth within a range of 0.2 to 0.4 μ

m measured from the semiconductor surface on the light-entry side;

a charge storage layer constituting another photoelectric conversion unit belonging to the second group is formed at a depth within a range of 1.2 to 1.4 μ

m measured from the semiconductor surface on the light-entry side;

a charge storage layer constituting one of the photoelectric conversion units belonging to the third group is formed at a depth within a range of 0.1 to 0.3 μ

m measured from the semiconductor surface located on the light-entry side; and

a charge storage layer constituting another photoelectric conversion unit belonging to the third group is formed at a depth within a range of 0.8 to 1.0 μ

m measured from the semiconductor surface on the light-entry side.

16. A solid-state image sensor according to claim 1, further comprising:

a second amplifier unit that individually amplifies signals generated based upon outputs from each of the four or more photoelectric conversion units by applying gains different from one another.

17. A solid-state image sensor according to claim 1, further comprising:

a vertical signal line that receives signals generated based upon outputs from each of two or more photoelectric conversion units among the four or more photoelectric conversion units, with timing with which one signal is received different from timing with which another signal is received;

a variable gain amplifier that amplifies signals in the vertical signal line or signals corresponding to the signals in the vertical signal line; and

a gain control unit that controls a gain at the variable gain amplifier in correspondence to spectral sensitivity characteristics of the photoelectric conversion units corresponding to the signals amplified by the variable gain amplifier.

9. A solid-state image sensor, comprising:

four or more photoelectric conversion units having spectral sensitivity characteristics different from one another; and

color filters having spectral transmittance characteristics different from one another, each of which is in correspondence to one of N (N represents an integer less than a quantity of the four or more photoelectric conversion units and equal to or greater than three) groups of photoelectric conversion units, a plurality of photoelectric conversion units among the four or more photoelectric conversion units belonging to each of the N groups, wherein;

the color filters are disposed on a light-entry side of the plurality of photoelectric conversion units belonging to each specific group; and

charge storage layers each constituting one of the plurality of photoelectric conversion units belonging to the specific group are disposed in alignment with one another along a direction in which light enters.

10. A solid-state image sensor according to claim 9, wherein:

the quantity of the four or more photoelectric conversion units is six, N is equal to three and a quantity of photoelectric conversion units belonging to each group is two.

13. A solid-state image sensor according to claim 10, wherein:

the three groups each include a first photoelectric conversion unit with a charge storage layer thereof disposed on a light-entry side and a second photoelectric conversion unit with a charge storage layer thereof disposed on a side opposite from the light-entry side;

the three first photoelectric conversion units in the three groups are formed so as to satisfy a first condition and the three second photoelectric conversion units in the three groups are formed so as to satisfy a second condition; and

the first condition stipulates that the charge storage layers each constituting one of the three first photoelectric conversion units assume positions with a uniform depth measured from a semiconductor surface on the light-entry side and the second condition stipulates that the charge storage layers each constituting one of the three second photoelectric conversion units assume positions with a uniform depth measured from the semiconductor surface on the light-entry side.

14. A solid-state image sensor according to claim 10, wherein:

the three groups each include a first photoelectric conversion unit with a charge storage layer thereof disposed on a light-entry side and a second photoelectric conversion unit with a charge storage layer thereof disposed on a side opposite from the light-entry side;

the three first photoelectric conversion units in the three groups and the three second photoelectric conversion units in the three groups are formed so that at least one of a first condition and a second condition is not satisfied; and

the first condition stipulates that the charge storage layers each constituting one of the three first photoelectric conversion units assume positions with a uniform depth measured from a semiconductor surface on the light-entry side and the second condition stipulates that the charge storage layers each constituting one of the three second photoelectric conversion units assume positions with a uniform depth measured from the semiconductor surface on the light-entry side.

18. A solid-state image sensor made up with an array of a plurality of pixels in three different types of pixels having at least three distinct characteristics, the three distinct characteristic being different from one another, comprising:

two different types of photoelectric conversion units disposed at each of the three different types of pixels and assuming spectral sensitivity characteristics that are different from each other; and

an amplifier unit disposed at each of the pixels.