Embodiments of the present invention provide an improved method for fabrication of fin field effect transistors (finFETs). Sacrificial regions are formed on a semiconductor substrate. Spacers are formed adjacent to two sides of the sacrificial regions. Fins are formed based on the spacers. One set of spacers is treated as dummy spacers, and is removed prior to fin formation, leaving the other set of spacers to be used for forming fins on the final semiconductor structure. All the fins on the final semiconductor structure are formed from spacers on one side of the sacrificial material. This reduces variation in width of the fins.