Ion beam etching of cryoelectronic devices on the basis of cuprate superconductors

Within the presented work there was built up a complex vacuum system which was especially designed for the deposition and patterning of high-Tc superconducting thin films an multilayers. With the help of the so called Inverted Cylinder Magnetron there were sputtered epitaxial and c-axis oriented YBa2Cu2O7-x thin films on (100) SrTiO3 substrates with Tco ≥ 88 K and jc (77K,B=O) ≥ 2.106 A/CM2. The deposition process was especially optimized for a good spatial homogenity of the electrical properties and a constant film thickness over the hole substrate allowing to use the films in cryoelectronic devices. Moreover it was possible to produce amorphous YBa2Cu3Oy films with the same magnetron source. These films were shown to have no noticeable degradation effect on the electrical properties of superconducting microbridges covered by the amorphous material. Because of their very good time stability these films were used both as isolating or passivating layers in cryoelectronic devices and as a technological material in different processes e.g. as making material. Applying the ion beam etching (IBE) to high Tc materials structure sizes in the submicron range are possible using an effective sample cooling during the milling process. (orig.)