Solid-state imaging element having image signal overflow path

• US 8,023,024 B2
• Filed: 09/20/2004
• Issued: 09/20/2011
• Est. Priority Date: 06/08/1998
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Yonemoto, Kazuya, Suzuki, Ryoji, Ueno, Takahisa, Shiono, Koichi
• Primary Examiner(s): WHIPKEY, JASON T
• Application Number:
  US10/945,519
• Publication Number:
  US 20050036051A1
• Time in Patent Office: 2,556 Days
• Field of Search: 348/308, 257/292, 257/225, 257/226, 257/227, 257/228, 257/229, 257/230, 257/231, 257/232, 257/233, 257/234, 250/208.1
• US Class Current: 348/308
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14612 involving a transistor
• CPC Class Codes: H01L 27/14638 Structures specially adapted for transferring the charges across the imager perpendicular to the imaging plane
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/40 Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled
• CPC Class Codes: H04N 25/441 by reading contiguous pixels from selected rows or columns of the array, e.g. interlaced scanning
• CPC Class Codes: H04N 25/65 applied to reset noise, e.g. KTC noise related to CMOS structures by techniques other than CDS
• CPC Class Codes: H04N 25/767 Horizontal readout lines, multiplexers or registers
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
• CPC Class Codes: H04N 25/778 comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself
• CPC Class Codes: H04N 3/1512 for MOS image-sensors, e.g. MOS-CCD H04N3/1581 takes precedence
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

Since the great number of elements constituting a unit pixel having an amplification function would hinder reduction of pixel size, unit pixel n,m arranged in a matrix form is comprised of a photodiode, a transfer switch for transferring charges stored in the photodiode, a floating diffusion for storing charges transferred by the transfer switch, a reset switch for resetting the floating diffusion, and an amplifying transistor for outputting a signal in accordance with the potential of the floating diffusion to a vertical signal line, and by affording vertical selection pulse φVn to the drain of the reset switch to control a reset potential thereof, pixels are selected in units of rows.

Claims

1. A solid state imaging element comprising:

an amplifying switch having a gate electrically connected to a floating diffusion and a drain electrically connected to a pixel power source;

a transfer switch having a source being said floating diffusion and a drain being a photodiode,

wherein an overflow path is between said photodiode and a contact region, said contact region being electrically connected to said pixel power source,

wherein said overflow path includes a channel stop, said channel stop having a first conductivity type.

2. A solid-state imaging element as claimed in claim 1, wherein said photodiode and said contact region are of a conductivity type opposite to the first conductivity type.

3. A solid-state imaging element as claimed in claim 1, wherein a region is between a substrate and said channel stop, said region being of said conductivity type opposite to the first conductivity type.

4. A solid-state imaging element as claimed in claim 3, wherein a dopant concentration of said photodiode and said contact region is greater than a dopant concentration of said region.

5. A solid-state imaging element as claimed in claim 3, wherein said region physically contacts said photodiode and said contact region.

6. A solid-state imaging element as claimed in claim 3, wherein said overflow path includes a LOCOS oxide film, said channel stop being between said LOCOS oxide film and said region.

7. A solid state imaging element comprising:

an amplifying switch having a gate electrically connected to a floating diffusion and a drain electrically connected to a pixel power source;

a transfer switch having a source being said floating diffusion and a drain being a photodiode,

wherein an overflow path is between said photodiode and a contact region, said contact region being electrically connected to said pixel power source,

wherein said amplifying switch is an enhancement type transistor.

8. A solid state imaging element comprising:

an amplifying switch having a gate electrically connected to a floating diffusion and a drain electrically connected to a pixel power source;

a transfer switch having a source being said floating diffusion and a drain being a photodiode;

a reset switch having a source being said floating diffusion and a drain being electrically connected to a vertical selection line,

wherein an overflow path is between said photodiode and a contact region, said contact region being electrically connected to said pixel power source,

wherein a matrix has a row (n) of pixels and a row (n+1) of pixels, each unit pixel (n, m) in said row (n) of pixels including said transfer switch and said reset switch,

wherein each unit pixel (n+1, m) in said row (n+1) includes another transfer switch and another reset switch, said another reset switch having a drain electrically connected to another vertical selection line.

9. A solid state imaging element comprising:

an amplifying switch having a gate electrically connected to a floating diffusion and a drain electrically connected to a pixel power source;

a transfer switch having a source being said floating diffusion and a drain being a photodiode,

wherein an overflow path is between said photodiode and a contact region, said contact region being electrically connected to said pixel power source,

wherein said transfer switch is an enhancement type transistor.