CHARACTERISING SENSITIVE SUBMICRO-BI-HALL PROBE SENSORS OF LIFT-OFF TECHNIQUES FOR APPLICATIONS IN SCANNING HALL PROBE MICROSCOPY(SHPM)

Hussein Ali Mohammed and Ayoub Abdulwahid Bazzaz*

ABSTRACT

Bismuth Hall (Bi-Hall) sensors with an active size range of (75nm-2μm) manufactured by electron beam lithography and lift-off techniques for applications in scanning Hall probe microscopy(SHPM) were systematically characterised for functional device size. Using higher Hall probe currents the miniumum detectable field of 100nm probes, at room temperature and dc currents of 5A is found to be Bmin=0.9mT/Hz0.5 with a scope of >10 reduction factor. This is significantly lower than those in similar samples manufactured by focussed ion beam (FIB) milling of continuous Bi films. Our finding suggests that the elimination of FIB damage and Ga+ ion incorporation through the use of lift-off techniques could produce superior figures of merit. Further ways in which the 300K performance of our sensors could be improved too.

Keywords: Sub-micro-Bi-Hall probe, lift-off techniques, scanning Hall probe microscopy.