Batch Fabrication of Algan/Gan-Based Hall Sensors for Magnetic Field Sensing

Hall-effect-based magnetic field sensing has a wide range of application domains including power systems, power electronics and electrical machinery. GaN-based Hall sensors have been demonstrated to have a stable and good performance over a wide temperature range of 50 K to 500 K. Commercial viability of such high-performance sensors could be enhanced through batch fabrication, which economizes cost of production. However, batch fabrication should ensure high yield and consistency in device performance across the batch. This paper proposes a batch fabrication methodology for Hall sensors on AlGaN/GaN heterostructures, grown on both Si and SiC substrates. Following these process steps, a 3*3 array of GaN-on-Si Hall sensors and of GaN-on-SiC Hall sensors are manufactured. The individual Hall sensors are characterized at temperatures of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$100 ~\mathrm{K}, 300 ~\mathrm{K}$</tex> and 500 K. The Hall-effect measurements are carried out up to magnetic field strengths of 2 T. The devices exhibit good linearity at different temperatures, and the device-to-device variation in performance is found to be quite low.