Image sensor and associated fabricating method

An image sensor, comprising:

• a substrate having a front side and a back side, wherein the substrate includes a first pixel and a second pixel each having:
• a first common node and a second common node heavily doped with dopants of a first conductivity type, the first and second common nodes being within the substrate and abutting the front side 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 side of the substrate, and the sensing node being between the first and second common nodes;
• an interconnect structure, wherein the front side of the substrate faces the interconnect structure;
• a distributed Bragg reflector (DBR) between the front side of the substrate and the interconnect structure, at least a portion of the DBR extending into the substrate between the first and second pixels;
• a first contact plug passing through the DBR and coupling the first and second common nodes to the interconnect structure;
• and
• a second contact plug passing through the DBR and coupling the sensing node to the interconnect structure.

An image sensor, comprising:

• a substrate having a front surface and a back surface;
• a photodiode (PD) within the substrate and abutting the front surface of the substrate;
• a floating diffusion regions (FD) within the substrate and abutting the front surface of the substrate;
• a gate at the front surface of the substrate between the PD and FD;
• 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 gate to the interconnect structure;
• and
• a second contact plug passing through the DBR and coupling the FD to the interconnect structure.