Fin-shaped AlGaN/GaN high electron mobility magnetoresistive sensor device

Abstract

A good magnetic field sensor should exhibit high sensitivity, low power consumption, and low output offset to accurately detect small fields. In this work, the high sensitivity in magnetoresistance variation (ΔR) is achieved by the AlGaN/GaN fin-shaped high electron mobility structure, in comparison to that of planar structures. A physical based analysis is presented to describe the influence of the fin width dimension on the ΔR dependency under magnetic fields. The sensitivity is expressed as a function of geometric parameters, electron mobility, and two-dimensional electron sheet density, with relaxation of polarization, shoulder density distribution, and sidewall trapped charges considered. Devices were fabricated, and a high sensitivity is observed in laboratory measurements on devices at narrower fin widths. At the fin width of 50 nm, the measured device has a sensitivity of 0.76 Ω/μΤ2 at the magnetic flux of 85 μΤ. The sensor's power consumption is as low as 48 μW, and the minimum magnetic flux detectable is at 20 μΤ.