Fine structuring of magnetic and high-Tc superconducting ceramic oxides in an HCI plasma

Abstract An anisotropic dry etch process using an HCl plasma has been developed to etch ferrites, garnets and the new high- T c superconducting ceramic oxide YBa 2 Cu 3 O 7−δ . Although from the thermodynamical point of view no volatile reaction products are formed the etch rate as compared to Ar sputter etching is increased, profuse are steeper and the selectivity towards the masking material is enhanced. Deep trenches have been etched in ferrite and narrow lines in superconducting thin films. After treatment these structures are found to be superconducting with zero resistivity at 80 K. The limited steepness (up to about 70°) of the patterns is a result of the characteristics of the chemically enhanced sputter etch process. These are investigated by model experiments and computer simulation.