Raman microprobe analysis of patterned Tl-2212 thin films

Abstract

We have used MicroRaman spectroscopy to evaluate the effects of ion-milling on the exposed edges of patterned Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/ (Tl-2212) lines. Raman microprobe has previously been used to evaluate oxygen loss at the edges of patterned YBCO lines. The results indicated that appreciable oxygen loss was caused by ion-milling under certain conditions. oxygen loss at the edges will decrease non-uniformly the effective width of the superconducting line. This can, in turn, impact the electrical characteristics of patterned devices. Using the 633 nm lined of a HeNe laser, we have measured the Raman spectrum scanning across patterned and unpatterned regions of several Tl-2212 films with a mapping stage. It is well known that the Raman peak at /spl ap/497 cm/sup -1/ corresponds to the Cu-O(2) stretching mode and is correlated with the superconducting transition temperature of the material. No appreciable variation in the center frequency of the Cu-O(2) peak was observed indicating thallium cuprate films are not degraded by our patterning process, even at the edges. Variations in the power handling of Tl-2212 co-planar lines, as determined by measurement of the Third Order Intercept, were not correlated with the Raman results.