Development of a micromachining process for the fabrication of a superconductor magnetic-field sensor

Abstract

This paper reports an effort to introduce high temperature superconductor (HTS) into the MEMS (microelectromechanical systems) field, to develop fabrication procedures suitable for HTS, and using them to fabricate a prototype superconductor microsensor for magnetic field detection. The prototype device fabricated is a sensor based on the giant magnetoresistivity of a high temperature superconductor around its critical temperature. It was fabricated using optical lithography and electrodeposition of Tl₁Ba₂Ca₂Cu₃O_x (Tl-1223) type high T _C superconductors. The test results of the prototype sensor fabricated show that the prototype sensor has a very high magnetoresistivity at medium to strong magnetic field strength and low magnetoresistivity at weak magnetic field. Our work suggests that in order to develop a high precision magnetic sensor for the detection of very weak magnetic fields, other HTS materials with less flux pinning effect and more weak links need to be pursued. The MEMS fabrication process developed is simple, repeatable, and applicable to microfabrication of other types of superconductor devices.