Experimental research on the sensitivity and noise level of bipolar and CMOS integrated magnetotransistors and judgement of their applicability in weak-field magnetometers

Abstract

Experimental investigations of the sensitivity and level of inherent noise of CMOS and bipolar magnetic sensors at temperatures of 300 and 77 K have been carried out. The absolute sensitivities of CMOS sensors are 4 and 20 V T -1 at temperatures of 300 and 77 K, respectively, while the equivalent noise fields at the central frequency of 1 kHz are 7 μT Hz − 1 2 at 300 K and 1.5 μT Hz − 1 2 at 77 K. The absolute sensitivities of bipolar two-collector magnetotransistor (BTMT) sensors are 1.2 and 30 V T −1 at temperatures of 300 and 77 K, respectively, while the equivalent noise fields at the central frequency of 1 kHz are 2 μT Hz − 1 2 at 300 K and 100 nT Hz − 1 2 at 77 K.