icroprobe Analysis of Patterned T1-2212 Thin Films

We have used MicroRaman spectroscopy to evaluate the effects of ion-milling on the exposed edges of patterned TI,Ba,CaCu,O, (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 o f the superconducting line. This can, in turn, impact the electrical characteristics of patterned devices. Using the 633 nm line of a HeNe laser, we have measured the Raman spectrum scanning across patterned and unpatterned regions of several TI- 2212 films with a mapping stage. It is well known that the Raman peak at = 497 cm" corresponds to the Cu-0(2) stretching mode and is correlated with the superconducting transition temperature of the material. No appreciable variation in the center frequency of the Cu-0(2) peak was observed indicating that thallium cuprate films are not degraded by our patterning process, even at the edges. Variations in the power handling of TI-2212 co-planar lines, as determined by measurement o f the Third Order Intercept, were not correlated with the Raman results.