CURRENT-INDUCED LOCAL OXIDATION OF METAL-FILMS - MECHANISM AND QUANTUM-SIZE EFFECTS

A novel route is introduced for oxidizing thin metal films with nanome ter-scale resolution. By locally subjecting Ti and Nb films to high in -plane current densities, metal-oxide tunneling barriers are formed in a self-limiting fashion. The oxidation is triggered by current-induce d atomic rearrangements and local heating. At the final stages of the barrier formation, when only atomic-scale channels remain unoxidized, the oxidation rate decreases drastically while the conductance drops i n steps of about 2e(2)/h. This behavior gives evidence of ballistic tr ansport and a superior stability of such metallic nanowires against cu rrent-induced forces compared with the bulk metal. (C) 1998 American I nstitute of Physics. [S0003-6951(98)04741-X].