Abstract: An image sensor comprising a semiconductor substrate and a trench isolation structure that is formed in the semiconductor substrate, wherein the trench isolation structure sequentially includes, from an outer portion to an inner portion of the trench isolation structure, a first oxide layer, a nitride layer, a second oxide layer and a semiconductor material layer that respectively extend in a thickness direction of the semiconductor substrate, such that a semiconductor-oxide-nitride-oxide-semiconductor structure is formed from the semiconductor substrate to the inner portion of the trench isolation structure via the outer portion of the trench isolation structure.