High-sensitivity Hall sensors using GaInAs/AlInAspseudomorphic heterostructures

Overview & Synopsis

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 9.84×1011 cm−2 and a high mobility of 13 000 cm2 V−1 s−1 at room temperature have been obtained. A physical model of the structure including a self-consistent description of the coupled Schrödinger 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 °C−1 between −80 and 85 °C is obtained. High signal-to-noise ratios corresponding to minimal detectable fields of 350 nT Hz−1/2 at 100 Hz-1/2 and 120 nT Hz−1/2 at 1 kHz have been measured.