A fin field effect transistor (FET) including a fin structure and a method for forming the fin FET are provided. In an exemplary method, the fin FET can be formed by forming at least one fin seed, including a top surface and sidewalls, on a substrate. A first semiconductor layer can then be formed at least on the sidewalls of the at least one fin seed. A second semiconductor layer can be formed on the first semiconductor layer. The second semiconductor layer and the at least one fin seed can be made of a same material. The first semiconductor layer can be removed to form a fin structure including the at least one fin seed and the second semiconductor layer.