Fin formation for semiconductor device

A method of fabricating a semiconductor structure includes forming a plurality of semiconductor fins disposed on a semiconductor substrate, wherein at least one of the fins is an unwanted fin including a semiconductor material; providing a conformal protective layer over the plurality of semiconductor fins; forming a mask having an opening over the unwanted fin; removing a portion of the unwanted fin to expose a fin spike; oxidizing the fin spike to form an oxidized semiconductor material; and removing the oxidized semiconductor material to expose a fin base.