Study of GaN Dual-Drain Magnetic Sensor Performance at Elevated Temperatures

For the first time, we report on the superior performance of the dual-drain gallium nitride (GaN) magnetic field-effect transistor (MagFET) at elevated temperatures. The IV characteristics of the devices reported here were collected under dc conditions and tested at elevated temperatures, 300, 323, 373, and 448 K using a custom-made heating stage, with a thermal feedback loop to accurately control the temperature. Light exposure experiments were conducted during raised temperature levels using an LED light source of wavelength 470 nm. The relative sensitivity of the GaN dual-drain MagFET was calculated and demonstrated a degradation from 9.78%T ^-1 at 300 K to 8.36%T ^-1 at 323 K, 6.10%T ^-1 at 373 K, and 3.79%T ^-1 at 448 K. This is equal to a small sensitivity decrease of 0.04%T ^-1 /K. It is proposed that the observed reduction in sensitivity reported herein is due to increased phonon scattering in the 2-D electron gas channel. Despite this reduced sensitivity at elevated temperatures, the lowest sensitivity measured at 448 K surpasses those reported for silicon competitors.