Solid-state image sensor

Patent metadata

Field	Value
Publication number	US-9620558-B2
Application number	US-201314436133-A
Country	US
Kind code	B2
Filing date	Oct 21, 2013
Priority date	Oct 19, 2012
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A solid-state image sensor includes: a pixel array that includes first pixels, each having first and second photoelectric conversion units, and second pixels, each having third and fourth photoelectric conversion units; first to fourth transfer gates via which a signal charge respectively generated in the first to fourth photoelectric conversion units is respectively transferred to first to fourth charge voltage conversion units. At least one of a gate width, a gate length and an installation position of at least one transfer gate among the first to fourth transfer gates is altered to achieve uniformity in voltage conversion efficiency at the first to fourth charge voltage conversion units.

First claim

The invention claimed is:

1. A solid-state image sensor, comprising:
a pixel array that includes first pixels, each having a first photoelectric conversion unit and a second photoelectric conversion unit arranged along a first direction, and second pixels, each having a third photoelectric conversion unit and a fourth photoelectric conversion unit arranged along a second direction;
a first transfer gate via which a signal charge generated in the first photoelectric conversion unit is transferred to a first charge voltage conversion unit;
a second transfer gate via which a signal charge generated in the second photoelectric conversion unit is transferred to a second charge voltage conversion unit;
a third transfer gate via which a signal charge generated in the third photoelectric conversion unit is transferred to a third charge voltage conversion unit; and
a fourth transfer gate via which a signal charge generated in the fourth photoelectric conversion unit is transferred to a fourth charge voltage conversion unit, wherein:
at least one of a gate width, a gate length and an installation position of at least one transfer gate among the first transfer gate, the second transfer gate, the third transfer gate and the fourth transfer gate is altered so as to achieve uniformity in voltage conversion efficiency at the first charge voltage conversion unit, the second charge voltage conversion unit, the third charge voltage conversion unit and the fourth charge voltage conversion unit; and
the first transfer gate and the second transfer gate are formed so as to assume a substantially identical gate width or gate length, the third transfer gate and the fourth transfer gate are formed so as to assume a substantially identical gate width or gate length, and installation positions at which the first transfer gate and the second transfer gate are disposed in the first pixels and installation positions at which the third transfer gate and the fourth transfer gate are disposed in the second pixels are substantially identical.

2. The solid-state image sensor according to claim 1 , wherein:
the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit and the fourth photoelectric conversion unit are formed to achieve substantially identical dimensions; and
the first transfer gate and the second transfer gate are disposed respectively at longer sides of the first photoelectric conversion unit and the second photoelectric conversion unit in the first pixels, and the third transfer gate and the fourth transfer gate are disposed respectively at shorter sides of the third photoelectric conversion unit and the fourth photoelectric conversion unit in the second pixels.

3. The solid-state image sensor according to claim 1 , wherein:
the first photoelectric conversion unit, the second photoelectric conversion unit, the third photoelectric conversion unit and the fourth photoelectric conversion unit are formed to achieve substantially identical dimensions; and
the first transfer gate and the second transfer gate are disposed at corners located at ends of a diagonal running through the first pixels and the third transfer gate and the fourth transfer gate are disposed at corners located at ends of a diagonal running through second pixels.

4. A solid-state image sensor, comprising:
a pixel array that includes first pixels, each having a first photoelectric conversion unit and a second photoelectric conversion unit arranged along a first direction, and second pixels, each having a third photoelectric conversion unit and a fourth photoelectric conversion unit arranged along a second direction;
a first transfer gate via which a signal charge generated in the first photoelectric conversion unit is transferred to a first charge voltage conversion unit;
a second transfer gate via which a signal charge generated in the second photoelectric conversion unit is transferred to a second charge voltage conversion unit;
a third transfer gate via which a signal charge generated in the third photoelectric conversion unit is transferred to a third charge voltage conversion unit; and
a fourth transfer gate via which a signal charge generated in the fourth photoelectric conversion unit is transferred to a fourth charge voltage conversion unit, wherein:
at least one of a gate width, a gate length and an installation position of at least one transfer gate among the first transfer gate, the second transfer gate, the third transfer gate and the fourth transfer gate is altered so as to achieve uniformity in voltage conversion efficiency at the first charge voltage conversion unit, the second charge voltage conversion unit, the third charge voltage conversion unit and the fourth charge voltage conversion unit;
the first transfer gate and the second transfer gate are disposed in the first pixels at positions different from installation positions at which the third transfer gate and the fourth transfer gate are disposed in the second pixels; and
a gate width or a gate length of transfer gates made up with the first transfer gate and the second transfer gate and a gate width or a gate length of transfer gates made up with the third transfer gate and the fourth transfer gate are varied in correspondence to a length of sides of the first photoelectric conversion unit and the second photoelectric conversion unit at which the first transfer gate and the second transfer gate are disposed and a length of sides of the third photoelectric conversion unit and the fourth photoelectric conversion unit at which the third transfer gate and the fourth transfer gate are disposed.

5. A solid-state image sensor, comprising:
first pixels each including a first photoelectric conversion unit, which includes photoelectric conversion areas divided from each other along a horizontal direction, and a plurality of first transfer gates via which electric charges resulting from photoelectric conversion executed in the first photoelectric conversion unit are transferred to first charge voltage conversion units from the first photoelectric conversion unit; and
second pixels each including a second photoelectric conversion unit, which includes photoelectric conversion areas divided from each other along a vertical direction, and a plurality of second transfer gates via which electric charges resulting from photoelectric conversion executed in the second photoelectric conversion unit are transferred to second charge voltage conversion units from the second photoelectric conversion unit, wherein:
installation positions at which the first transfer gates are disposed at each of the first pixels are substantially identical to installation positions at which the second transfer gates are disposed at each of the second pixels.

6. A solid-state image sensor, comprising:
first pixels each including a first photoelectric conversion unit, which includes photoelectric conversion areas divided from each other along a horizontal direction, and a plurality of first transfer gates via which electric charges resulting from photoelectric conversion executed in the first photoelectric conversion unit are transferred to first charge voltage conversion units from the first photoelectric conversion unit; and
second pixels each including a second photoelectric conversion unit, which includes photoelectric conversion areas divided from each other along a vertical direction, and a plurality of second transfer gates via which electric charges resulting from photoelectric conversion executed in the second photoelectric conversion unit are transferred to second charge voltage conversion units from the second photoelectric conversion unit, wherein:
a gate width or a gate length assumed for the first transfer gates is different from the ga

Assignees

• Nikon Corp

Inventors

• Suzuki Satoshi

Classifications

• H04N25/677

  for reducing the column or line fixed pattern noise · CPC title

• H04N25/616

  involving a correlated sampling function, e.g. correlated double sampling [CDS] or triple sampling · CPC title

• H04N25/77

  Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components · CPC title

• H04N25/78

  Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters · CPC title

• H01L27/14812 Primary

  Electricity · mapped topic