Agglomeration and diffusion of ag associated with electrical contacts on single crystal Bi2Sr2CaCu2Oy

For the purpose of obtaining good small-area electrical contacts on single crystals of Bi2Sr2CaCU2Oy (Bi-2312) for transport study, the nature of the Ag film on a Bi-2212 single crystal was examined. hg films of similar to 100 nm thickness deposited on cleaved surfaces of Bi-2212 crystals and annealed at 500 degrees C have been studied far microstructural changes and diffusive behavior by scanning electron microscopy (SEM) and electron probe micro-analysis (EPMA). it is found that the Ag films undergo a thermally activated softening/roughening on annealing. On prolonged annealing, film break-up and segregation takes place, accompanied by a small diffusion of Ag into and along the surface of Bi-2212. Based on these results, a method for electrical contact formation on a Bi-2212 crystal cleaved surface is presented.