Title:
イメージセンサ
Document Type and Number:
Japanese Patent JP4369885
Kind Code:
B2
Abstract:
A buried oxide is provided in a substrate of a photodiode so as to be opposed to a cathode and is in contact with a lower end of a depletion layer. The buried oxide is polarized owing to charges forming the depletion layer and thus works as a capacitor. A capacitor formed in the depletion layer and the additional capacitor made by the buried oxide are, therefore, connected in series, which reduces a total junction capacitance Cs. Increase in photo-detection voltage Vs results in according to an equation, Vs=Qp/Ct, since an amount of photocharge Qp is constant. The increase in the photo-detection voltage Vs allows an improvement in the SN ratio of the photodiode. Further, easy formation of the buried oxide, for example, by implanting oxygen ions, permits low-cost manufacturing of the photodiode.
Inventors:
Sumitaka Goto
Application Number:
JP2005072261A
Publication Date:
November 25, 2009
Filing Date:
March 15, 2005
Export Citation:
Assignee:
Seiko Instruments Inc.
International Classes:
H01L31/10; H01L27/146
Domestic Patent References:
| JP2004111762A | ||||
| JP2004179217A | ||||
| JP8139356A | ||||
| JP8139355A | ||||
| JP62016568A | ||||
| JP2001320078A |
Attorney, Agent or Firm:
Yoshiharu Matsushita