Effect of geometry on the frequency limit of GaAs/AlGaAs 2-Dimensional Electron Gas (2DEG) Hall effect sensors

TL;DR

This study experimentally examines how the geometry of GaAs/AlGaAs 2DEG Hall sensors affects their frequency limits, revealing the trade-offs between sensitivity and frequency performance for different contact designs.

Contribution

It provides the first detailed analysis of how contact geometry influences the frequency limit of GaAs/AlGaAs Hall sensors, without relying on current spinning.

Findings

Frequency limit varies with contact geometry.

Removing current spinning increases frequency limit.

Trade-off between sensitivity and frequency performance.

Abstract

In this work, we experimentally investigate the frequency limit of Hall effect sensor designs based on a 2 dimensional electron gas (2DEG) gallium arsenide/aluminum gallium arsenide (GaAs/AlGaAs) heterostructure. The frequency limit is measured and compared for four GaAs/AlGaAs Hall effect sensor designs where the Ohmic contact length (contact geometry) is varied across the four devices. By varying the geometry, the trade-off in sensitivity and frequency limit is explored and the underlying causes of the frequency limit from the resistance and capacitance perspective is investigated. Current spinning, the traditional method to remove offset noise, imposes a practical frequency limit on Hall effect sensors. The frequency limit of the Hall effect sensor, without current spinning, is significantly higher. Wide-frequency Hall effect sensors can measure currents in power electronics that operate at higher frequencies is one such application.