A method of generating a pixel array layout for an image sensor (wherein the image sensor includes a plurality of unit pixels, and each of the plurality of unit pixels includes a plurality of transistors) includes forming each unit pixel to include a shallow trench isolation (STI). The STI is between a deep trench isolation (DTI) area and one of a p-well region and source and drain regions of each transistor. The p-well region is below a gate of each of the transistors, and the DTI area is filled with at least two materials.