A method includes designing a layout of gate structures and diffusion regions of a plurality of devices, identifying an edge device of the plurality of devices, adding a dummy device next to the edge device and a dummy gate structure next to the dummy device resulting in a modified layout, and fabricating, based on the modified layout, at least one of a photolithography mask or at least one component in a layer of a semiconductor device. The dummy device shares a diffusion region with the edge device. A gate structure of the dummy device is one of two dummy gate structures added next to the edge device.