US Patent 9553025 Selective Fin-shaping process

A method of forming a fin field-effect transistor (FinFET) includes forming a plurality of fins on a substrate. The method further includes forming an oxide layer on the substrate, wherein a bottom portion of each fin of the plurality of fins is embedded in the oxide layer, and the bottom portion of each fin of the plurality of fins has substantially a same shape. The method further includes shaping at least one fin of the plurality of fins, wherein a top portion of the at least one fin has a different shape from a top portion of another fin of the plurality of fins.