US Patent 10373999 Image sensor and associated fabricating method

An image sensor is disclosed. The image sensor includes: a common node heavily doped with dopants of a first conductivity type, the common node being within the substrate and abutting the front surface of the substrate; and a sensing node heavily doped with dopants of a second conductivity type opposite to the first conductivity type, the sensing node being within the substrate and abutting the front surface of the substrate; an interconnect structure, wherein the front surface of the substrate faces the interconnect structure; a distributed Bragg reflector (DBR) between the front surface of the substrate and the interconnect structure; a first contact plug passing through the DBR and coupling the common node to the interconnect structure; and a second contact plug passing through the DBR and coupling the sensing node to the interconnect structure.