Device and a method of forming a device are disclosed. The method includes providing a crystalline-on-insulator (COI) substrate. The COI substrate includes at least a base substrate over a buried insulator layer. Through via (TV) contacts are formed within the substrate. The TV contact extends from a top surface of the base substrate to within the buried insulator layer. Upper interconnect levels are formed over the top surface of the base substrate. A lower redistribution (RDL) is formed over a bottom surface of the base substrate. The buried insulator layer corresponds to a first RDL dielectric layer of the lower RDL and protects the sidewalls of the TV contacts.