Nanowire devices and fin devices are formed in a first region and a second region of a substrate. To form the devices, alternating layers of a first material and a second material are formed, inner spacers are formed adjacent to the layers of the first material, and then the layers of the first material are removed to form nanowires without removing the layers of the first material within the second region. Gate structures of gate dielectrics and gate electrodes are formed within the first region and the second region in order to form the nanowire devices in the first region and the fin devices in the second region.