Multiple deep trench isolation (mdti) structure for cmos image sensor

Abstract

The present disclosure relates to a CMOS image sensor having a multiple deep trench isolation (MDTI) structure, and an associated method of formation. In some embodiments, a plurality of pixel regions is disposed within a substrate and respectively comprising a photodiode. The photodiode comprises a doped layer with a first doping type and an adjoining region of the substrate with a second doping type that is different than the first doping type. A boundary deep trench isolation (BDTI) structure is disposed between adjacent pixel regions. A multiple deep trench isolation (MDTI) structure overlies the doped layer of the photodiode. The MDTI structure comprises a stack of dielectric layers lining sidewalls of a MDTI trench. A plurality of color filters is disposed at the back-side of the substrate corresponding to the respective photodiode of the plurality of pixel regions and overlying the MDTI structure.