Effects of different ohmic contact widths and distances on the absolute sensitivity of two-dimensional hall sensor

Abstract

This research has investigated the effect of different ohmic contact widths and spacing (distances) on the perpendicular- and parallel-directional absolute sensitivity of silicon-based two-dimensional (2D) Hall sensors. The experimental sensors were of two configurations. The first configuration was of 100µm and 40µm in width (W) and spacing (S), while the other configuration was of 300µm in W and 60µm in S. The sensors were fabricated on a 20-30W.cm-resistivity p-type silicon substrate with five etched aluminum (Al) ohmic contacts. In the experiment, the perpendicular and parallel absolute sensitivity of the sensors were tested by varying the magnetic flux density from -5000 to 5000 Gauss (G). The findings revealed that the proposed sensors were capable of magnetic sensing in both perpendicular and parallel directions. Specifically, the perpendicular absolute sensitivity of the sensor with the 300µm contact width was 2.08 times higher than that with 100µm width. Meanwhile, the parallel absolute sensitivity characteristics associated with the two different contact distances (i.e. 40µm and 60µm) were similar. Thus, the ohmic contact width plays a more crucial role in the sensitivity enhancement of the Hall sensors.