Integrated device and method of forming the same

Abstract

Some embodiments relate to an integrated device, including: a substrate having a first refractive index, a first side, a second side, and a first and second region extending between the first side and the second side; a lower insulative grid structure within the substrate, the lower insulative grid structure having a first plurality of insulative segments arranged in a grid pattern and having a second refractive index, and extending between the first region of the substrate and the second region of the substrate; an upper insulative grid structure overlying the lower grid structure and comprising a second plurality of insulative segments that have outer sidewalls that are substantially aligned with outer sidewalls of the first plurality of insulative segments, the second plurality of insulative segments having a third refractive index that is greater than the second refractive index and lower than the first refractive index.