FinFET structures and methods of formation are disclosed. Fins are formed on a bulk substrate. A crystalline insulator layer is formed on the bulk substrate with the fins sticking out of the epitaxial oxide layer. A gate is formed around the fins protruding from the crystalline insulator layer. An epitaxially grown semiconductor region is formed in the source drain region by merging the fins on the crystalline insulator layer to form a fin merging region.