LOW-FIELD INHOMOGENEITY-INDUCED MAGNETORESISTANCE IN SILICON

Abstract

We show that inhomogeneity-induced magnetoresistance (IMR) in lightly doped silicon can be significantly enhanced through the injection of minority charge carriers, and then tuned by an applied current to have an onset at low magnetic fields. We designed an IMR device in which, the inhomogeneity is provided by the p–n boundary formed between regions where conduction is dominated by the minority and majority charge carriers respectively; application of a magnetic field distorts the current in the boundary region, resulting in large magnetoresistance. The room-temperature field sensitivity of our IMR device at low fields was remarkably improved, with magnetoresistance reaching 10% at 0.07 T and 100% at 0.2 T, approaching the performance of commercial giant magnetoresistance devices. The combination of high sensitivity to low magnetic fields and large high-field response should make this device concept attractive to the magnetic field sensing industry. Moreover, being based on a conventional silicon platform, it should be possible to integrate with existing silicon devices and so aid the development of silicon-based magnetoelectronics.