HIGH-SENSITIVITY HALL SENSORS USING GAINAS ALINAS PSEUDOMORPHIC HETEROSTRUCTURES/

In this work, we propose solutions based on band-gap engineering of II I-V heterostructures to develop new types of magnetic sensors using th e properties of a two-dimensional electron gas and the benefit of stra in in pseudomorphic channels. First, the optimization of the growth of pseudomorphic In0.75Ga0.25As/In0.52Al0.48As heterostructures by molec ular beam epitaxy is described. A low sheet electron density of 9.84x1 0(11) cm(-2) and a high mobility of 13 000 cm(2) V-1 s(-1) at room tem perature have been obtained. A physical model of the structure includi ng a self-consistent description of the coupled Schrodinger and Poisso n equations has been developed for a better understanding of the influ ence of the heterostructure design on its electronic properties. A sen sitivity of 580 V A(-1) T-1 with a temperature coefficient of -550 ppm degrees C-1 between -80 and 85 degrees C is obtained. High signal-to- noise ratios corresponding to minimal detectable fields of 350 nT Hz(- 1/2), at 100 Hz and 120 nT Hz(-1/2) at 1 kHz have been measured.