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

Abstract

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, 300K, 323K, 373K and 448K 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 470nm. The relative sensitivity of the GaN duel-drain MagFET was calculated and demonstrated a degradation from 9.78%T -1 at 300K, to 8.36%T -1 at 323K, 6.10%T -1 at 373K and 3.79%T -1 at 448K. This is equal to a small sensitivity decrease of 0.04%T -1 per Kelvin. It is proposed that the observed reduction in sensitivity reported herein is due to increased phonon scattering in 2DEG channel. Despite this reduced sensitivity at elevated temperatures, the lowest sensitivity measured at 448K surpasses those reported for silicon competitors.

Development of GaN Transducer and On-Chip Concentrator for Galvanic Current Sensing

“…The current imbalance of the MagHEMT can be measured on split contacts and its sensitivity (S) is calculated similar to previously reported in literature for MagFETs by the following expression [10]: 2where ID1 and ID2 are the currents from drain 1 and drain 2 respectively, in the presence of magnetic field (B), and Ioffset is the current difference in the absence of a magnetic field.…”

“…The advantages of a gallium nitride (GaN) heterostructure over conventional semiconductors make it a promising replacement for silicon-based Hall-effect devices in RF and power applications [8], [9]. Recently, we have demonstrated superior performance of the GaN sensors (ungated) at elevated temperatures [10] surpassing silicon counterparts [11]. In addition, silicon based Hall-effect sensors have a limited bandwidth of a few KHz, compound semiconductors including gallium arsenide and indium arsenide have enabled a detection bandwidth of tens of MHz [1].…”

A physics-based electrical model of a magnetically sensitive AlGaN/GaN HEMT

“…Besides the passive resistive sensors that rely on inhomogeneous narrow-gap semiconductors with high magnetoresistance [6], the emerging wide band-gap AlGaN/GaN hetero-junction technology has enabled the development of new class of the active magnetic sensors based on High-Electron Mobility Transistors (HEMTs) namely GaN MagHEMTs [7]- [10]. Owning to extremely high mobility µe (> 2000 cm 2 V -1 sec -1 ) of the electrons in 2-Dimensional Electron Gas (2DEG) channel [11], the first experimental GaN MagHEMTs have already exhibited a much higher sensitivity Sr (>17%) at room temperature [7][8][9][10] compared to their silicon counterparts.…”

Coil Design for Integration with GaN Hall-Effect Sensors

“…Furthermore, the innovative magneto-static FEA's methodology and results provide powerful insights into the spatial distribution of the magnetic field intensity at sensor active region prior to fabrication stage. In the present system, the current is galvanically monitored with a GaN Hall-effect sensor [9,13,14] that will be monolithically integrated with a normally-off GaN power switch. The initial step toward demonstrating a smart power integrated circuit is the coil design.…”