High-resolution MOS magnetic sensor with thin oxide in standard submicron CMOS process

Abstract

In this paper, new results obtained with an NMOS magnetic-field sensor made by an industrial 0.8 mu m CMOS process are presented. The major disadvantage of MOS magnetic sensors, a larger noise, can be overcome by the submicron CMOS process with 19 nm gate oxide, The device with W/L=60 mu m/50 mu m biased at saturation region has a resolution of 150 nT (Hz)(-1/2) at 1 kHz and 400 nT (Hz)(-1/2) at 100 Hz, respectively. Even when the device size is scaled down to W/L=6 mu m/5 mu m, the resolution still has the value of 1.5 mu T (Hz)(-1/2) at 1 kHz. The dependence of sensitivity and current-related sensitivity for various bias conditions is discussed in detail and a simple model to explain these trends is established.