during deposition the grain size decreases and the resistivity remains approximately the same with increasing argon pressure at relatively high oxygen concentrations the higher lead oxide pb 3 o 4 is formed the fact that only pbo has been previously observed in thermally evaporated pb films deposited under even higher oxygen partial pressure see van der drift a philips research report vol 21 1966 page 289 strongly indicates that the non equilibrium reactive ion beam sputtering process is basically different from a thermal evaporation process in film formation in addition the pb grains in the ion beam deposited films are randomly oriented as opposed to the strong preference toward a uniform orientation often exhibited by thermally evaporated lead films the ion beam sputter deposition of lead with a beam current on the order of 0 5 amps cm 2 and an oxygen partial pressure in the approximate range of 10 4 torr to 10 3 torr results in films comprising randomly oriented submicron lead grains interspersed in an insulating lead oxide matrix films made under these circumstances are smooth enough for use in josephson devices such as josephson tunnel junctions josephson junctions using the ion beam deposited films for the base electrode are hillock resistant over at least several thermal cycles between approximately 4 degrees kelvin and processing temperatures used in photolithography which are on the order of 360 degrees kelvin an example of an inventive josephson junction is shown in fig2 ion beam deposited lead and lead oxide film 32 forms the base electrode and is deposited on insulating substrate 31.