TEA CO2 laser ablation studies of Y-Ba-Cu-O

Abstract

Of the various lasers that have been used for the ablation of Y-Ba-Cu-O samples to form superconducting films from deposited products, UV excimer and visible systems have met with most success. TEA CO2 lasers provide an interesting, alternative, ablation source although, as yet, little work has been reported on the mechanisms involved at this longer wavelength.In this paper visible-UV spectroscopic and ion probe measurements on the ablation products from bulk Y-Ba-Cu-O targets irradiated using a TEA CO2 laser are reported. Information gained from the luminescent species recorded at various distances from the target and from non-species resolved ion-probe traces are reported and discussed. Relatively high plasma temperatures are duduced to occur at quite modest fluence levels. Etch-rate measurements show that material removal decreases beyond a certain fluence, probably as a result of shielding due to strong inverse bremmstrahlung absorption in the ablation plume. A comparison with similar studies conducted using the KrF excimer laser is made and the possible implications for film deposition discussed.