Systematics of excimer laser ablation: Thin film preparation of high T(sub c) material
Abstract
Excimer laser ablation was used to prepare thin films from bulk targets of Y-Ba-Cu-O, Sm-Ba-Cu-O, and Bi-Sr-Ca-Cu-O. The systematic variation in film thickness, stoichiometry, and microstructure, as a function of laser fluence and angle from the target surface normal was determined. At laser fluence above a few J sq cm the film composition is uniform over wide solid angles. Deposition rate increases with laser fluence. For the Sm and Bi based materials film stoichiometry replicates the target composition at high laser fluence. These results can be understood in terms of the sudden creation of a dense gas layer at the target surface, and unity sticking coefficients at the substrate. The Y based films, however, are deficient in Ba and Cu at such laser fluence. The effect of moderate temperature processing upon interface sharpness for GaAs and Si based substrates and several of the high T sub c materials was investigated.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- 1988
- Bibcode:
- 1988STIN...8825909N
- Keywords:
-
- Ablation;
- Excimer Lasers;
- High Temperature Superconductors;
- Thin Films;
- Deposition;
- Film Thickness;
- Fluence;
- Microstructure;
- Stoichiometry;
- Lasers and Masers