FREESTANDING STRUCTURES OF PEROVSKITE-TYPE OXIDE MATERIALS

摘要

A freestanding YBa2Cu3O7-(delta) or ferroelectric air bridge is disclosed. This structure is useful for membrane detectors and can be extended to applications in which the presence of a substrate can degrade electronic, thermal, and optical properties of the superconductor or ferroelectric structure. The air bridge is fabricated using conventional photolithography, ion-beam dry etching, and selective wet etching. In the preferred embodiment, a sacrificial dielectric layer is deposited between a supportive substrate and a layer of superconducting material. The dielectric layer is later etched away in selected regions to form the air bridge. Step coverage of epitaxial bridge layers has been achieved without significant degradation of the superconducting properties of YBa2Cu3O7-(delta) layers. Alternatively, YBa2Cu3O7-(delta) can be used as the sacrificial layer when a ferroelectric such as Pb(Zr,Ti)O3 is the desired air bridge material.