We have demonstrated controlled growth of epitaxial h-BN on a metal substrate using atomic layer deposition. This permits the fabrication of devices such as vertical graphene transistors, where the electron tunneling barrier, and resulting characteristics such as ON-OFF rate may be altered by varying the number of epitaxial layers of h-BN. Few layer graphene is grown on the h-BN opposite the metal substrate, with leads to provide a vertical graphene transistor that is intergratable with Si CMOS technology of today, and can be prepared in a scalable, low temperature process of high repeatability and reliability.