HIGH-SENSITIVITY HALL SENSORS USING GAINAS/ALINAS PSEUDOMORPHIC HETEROSTRUCTURES

In this work, we propose solutions based on band-gap engineering of III-V heterostructures to develop new types of magnetic sensors using the properties of a two-dimensional electron gas and the benefit of strain in pseudomorphic channels. First, the optimization of the growth of pseudomorphic In0.75Ga0.25As/In0.52Al0.48As heterostructures by molecular beam epitaxy is described. A low sheet electron density of 9.84x10(11) cm(-2) and a high mobility of 13 000 cm(2) V-1 s(-1) at room temperature have been obtained. A physical model of the structure including a self-consistent description of the coupled Schrodinger and Poisson equations has been developed for a better understanding of the influence of the heterostructure design on its electronic properties. A sensitivity 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.