A method for forming fin structures for a semiconductor device that includes a substrate and a dielectric layer formed on the substrate is provided. The method includes etching the dielectric layer to form a first structure, depositing an amorphous silicon layer over the first structure, and etching the amorphous silicon layer to form second and third fin structures adjacent first and second side surfaces of the first structure. The second and third fin structures may include amorphous silicon material. The method further includes depositing a metal layer on upper surfaces of the second and third fin structures, performing a metal-induced crystallization operation to convert the amorphous silicon material of the second and third fin structures to a crystalline silicon material, and removing the first structure.