Focused ion-beam modification and patterning of high-Tc superconductors

Abstract

High-resolution patterning of thin-film high temperature superconductors is necessary in the development of device applications of these new materials. Such fine-line structures are necessary in the fabrication of devices such as superconducting quantum interference devices (SQUIDs), transmission lines and others. Furthermore, high spatial resolution patterning can be an important tool in studying the fundamental properties of the films themselves. Focused ion beam patterning has recently been applied to YBaCuO thin films. The finely focused ion beam can produce patterns by local physical sputtering or through implant damage. These techniques have proven to be valuable for producing submicron superconducting structures in a reliable way. This paper describes the method of modification and patterning of high T thin films by focused ion beam implantation damage. For low ion doses, the film properties such as critical current and transition temperature are reduced monotonically with dose. At higher doses, the material is rendered non-superconducting locally. We show that micron-sized superconducting structures can be fabricated by this very simple one-step technique at ion doses in the range of 1012 to iO1 ions/cm2 with a 300 keY Si beam.