The layouts, device structures, and methods described above utilize dummy devices to extend the diffusion regions of edge structures and/or non-allowed structures to the dummy device. Such extension of diffusion regions resolves or reduces LOD and edge effect issues. In addition, treating the gate structure of a dummy device next to an edge device also allows only one dummy structure to be added next to the dummy device and saves the real estate on the semiconductor chip. The dummy devices are deactivated and their performance is not important. Therefore, utilizing dummy devices to extend the diffusion regions of edge structures and/or non-allowed structures according to design rules allows the resolution or reduction or LOD and edge effect issues without the penalty of yield reduction or increase in layout areas.