S/N study of micro-hall sensors made of single crystal InSb and GaAs

Abstract

Signal-to-noise (S/N) characteristics of various single crystal semiconductor micro-Hall sensors with an effectively magnetosensitive area less than 5 microns square are presented. Normal product sensitivity is typically 140 V/AT for an InSb sensor and 500 V/AT for a GaAs sensor. The magnetic sensitivity of a highly resistive GaAs micro-Hall sensor increases remarkably at a high electric field together with increasing current noise due to Gunn instability. A maximum magnetic sensitivity of 2.5 V/T was obtained. However, the S/N ratio of a GaAs sensor was much smaller than that of an InSb sensor with a high electron mobility. A high S/N ratio of 145 dB was obtained for an InSb micro-Hall sensor operated by an audio frequency of 1 kHz in a magnetic field of 0.1 T.