The Influence of the Dopant Concentration in a Silicon Film on the Magnetic Sensitivity of SOI Field-Effect Hall Sensors

Abstract

SOI field-effect Hall sensors (SOI FEHS) are characterized by enhanced functionality but low magnetic sensitivity. The main task of the present study is to search for a way to increase the magnetic sensitivity of such sensors. The results of the study on magnetically sensitive electric characteristics of the SOI FEHSs, obtained using the process and device simulation system Synopsys TCAD, are presented. Three-dimensional device simulation is carried out. The calculated Hall-gate characteristics of the SOI FEHS are obtained, which confirm an earlier proposed sensor physical model according to which, under certain conditions of SOI FEHS operation, a region of increased magnetic sensitivity appears. The influence of the dopant concentration in the sensor channel on magnetic sensitivity is studied. It is shown that the magnetic sensitivity of SOI FEHS triples at a concentration of phosphorus in a working layer of N_P = 10¹⁶ cm^–3. The extended dynamic range of the region of increased magnetic sensitivity (wider than 5 V) permits us to broaden the area of the sensor’s practical application by increasing its noise immunity. The calculated SOI FEHS characteristics agree closely with the earlier published parameters of the experimental devices.