Bias dependence of noise correlation in MAGFETs

In this paper, measurement results of noise power spectral density in p-channel split-drain MAGFETs operating under various levels of bias current are presented and discussed. It has been observed that correlation increases for decreasing levels of bias current. For currents below 5 μA, noise correlation is higher than 50%, rising rapidly towards total correlation. These results indicate that this type of magnetic sensor can be used for low level detection, contradicting what has been so far mentioned in the literature. Measurements were made for bias current ranging from 2 μA to circa 70 μA using MAGFETs manufactured in 0.8 μm CMOS with geometric aspect ratios of 10 μm/10 μm, 24 μm/24 μm and 24 μm/30 μm.