Patent ID: 7952121
Filing Date: 2011-05-31
Classification: H01L

Abstract:
1. An image sensor comprising: a charge storage portion for storing and transferring signal charges; a first electrode for forming an electric field storing the signal charges in said charge storage portion; a charge increasing portion for increasing the signal charges stored in said charge storage portion; and a second electrode for forming another electric field increasing the signal charges in said charge increasing portion, wherein the quantity of the signal charges storable in said charge storage portion has at least either of a structure that the plane area of said first electrode is larger than at least the plane area of said second electrode or a structure that the dielectric constant of a gate insulating film between said first electrode and said charge storage portion is at least larger than the dielectric constant of said gate insulating film between said second electrode and said charge increasing portion so that the quantity of the signal charges storable in said charge storage portion is not less than the quantity of the signal charges storable in said charge increasing portion, and wherein the signal charges are increased in said charge increasing portion due to impact ionization by the electric field formed from said second electrode.