Fabrication and characterization of Bismuth Hall sensors at room temperature

Small-scale Hall effect devices have attracted a great deal of research interest in recent years. It is well known that bulk single crystal of bismuth exhibit a large magnetoresistance effect and the recognition of this fact has stimulated a number of recent efforts to grow thin films of bismuth. Such films are useful in magnetic sensing applications. We fabricated Hall sensors having thickness of 30 nm and 50 nm of Bismuth using photolithography. Bismuth was deposited on to the surface of GaAs by evaporation teclinique. The properties of these sensors were then studied; dependences of the resistivity, and Hall coefficient on layer thickness were investigated at room temperature. Hall coefficients were calculated under the effect of a magnetic field. Results were then compared with the previously obtained values. Bismuth micro-Hall probes with dimensions as small as »0.25 pm x 0.25 pm produced by Focused Ion Beam (FIB) milling were also presented in this study. Hall coefficient was then calculated.