A method for forming a fin in a semiconductor device that includes a substrate, an insulating layer formed on the substrate, and a conductive layer formed on the insulating layer, includes forming a carbon layer over the conductive layer and forming a mask over the carbon layer. The method further includes etching the mask and carbon layer to form at least one structure, where the structure has a first width, reducing the width of the carbon layer in the at least one structure to a second width, depositing an oxide layer to surround the at least one structure, removing a portion of the oxide layer and the mask, removing the carbon layer to form an opening in a remaining portion of the oxide layer for each of the at least one structure, filling the at least one opening with conductive material, and removing the remaining portion of the oxide layer and a portion of the conductive layer to form the fin.