INTERDIFFUSION EFFECTS IN HIGH-T-C SUPERCONDUCTING STRUCTURES BY AUGER-ELECTRON SPECTROSCOPY

Microelectronic applications of high-T-c superconducting multilayers w ith intermediate buffer layers require superconducting films with high critical current densities, j(c), and uniform properties over the ent ire surface of interfacial regions. YBa2Cu3O7-x multilayer composite s amples, buffered with polycrystalline NiO films, were produced by reac tive magnetron sputtering on SrTiO3 substrates. The interfacial diffus ion phenomena, the thermal damage and the changes in elemental composi tion of such superconducting multilayer systems, e.g. Y-Ba-Cu-O/NiO/Y- Ba-Cu-O/SrTiO3, have been investigated by Auger electron spectroscopy (AES) depth profiling measurements before and after thermal annealing at temperatures between 125 and 625 degrees C. In addition, AES measur ements were carried out on post-annealed YBa2Cu3O7-x films deposited o n pure and NiO buffered silicon substrates to obtain information about the interdiffusion effects of possible NiO barrier layers applied as protection against Si diffusion. The experimental results presented he re demonstrate that YBa2Cu3O7-x/NiO/YBa2Cu3O7-x multilayer structures are useful systems in superconducting devices where less interfacial r eactions take place in a post-annealing temperature range around 250 d egrees C.