IMAGE SENSOR WHERE PHOTODIODE REGION IS EMBEDDED AND ITS MANUFACTURING METHOD

Title:

IMAGE SENSOR WHERE PHOTODIODE REGION IS EMBEDDED AND ITS MANUFACTURING METHOD

Document Type and Number:

WIPO Patent Application WO/2006/097978

Kind Code:

A1

Abstract:

A CMOS image sensor having a substantially large numerical aperture and an improved photosensitivity and its manufacturing method are provided. The image sensor comprises a pixel region (10) where pixels each having at least a photodiode, a reset transistor, and a source-follower transistor are formed and a peripheral circuit region (12) where a peripheral circuit for processing read signals read out of the pixel region is formed. The well region (PW2) of the pixel region is shallower than the well region (PW1) of the peripheral circuit region. A reset transistor or a source-follower transistor is formed in the shallow well region (PW2) of the pixel region (10), and a photodiode region (PHD2) is embedded under the well region (PW2) of each reset or source-follower transistor. By making such a structure, the photodiode region of each pixel can be embedded in a relatively shallow region from the surface of the substrate, and consequently the light entering through the substrate surface can be captured before its attenuation to enhance the photosensitivity. Since the photodiode region of each pixel can be embedded at relatively shallow position under the active element of the pixel, the substantial numerical aperture can be increased, and the photosensitivity is improved.

Inventors:

INOUE TADAO (JP)
YAMAMOTO KATSUYOSHI (JP)
OHKAWA NARUMI (JP)

Application Number:

PCT/JP2005/004322

Publication Date:

September 21, 2006

Filing Date:

March 11, 2005

Export Citation:

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Assignee:

FUJITSU LTD (JP)
INOUE TADAO (JP)
YAMAMOTO KATSUYOSHI (JP)
OHKAWA NARUMI (JP)

International Classes:

H01L27/146; H04N5/369; H04N5/3745

Foreign References:

JP2003282857A	2003-10-03
JPH11317512A	1999-11-16
JP2002016243A	2002-01-18
US20030228736A1	2003-12-11

Other References: