Reliability Study of GaN-Based Hall Sensors

Student: Alexis Krone

Degree: M.S., May 2021

Major Professor: Dr. David Huitink

Research Area(s):


Physical & Chemical Sensors

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  • Current magnetic field sensors use silicon-based substrates but break down under high temperatures and voltages.

  • As industry shifts to higher power electronics in uses such as cars, stable wide band gap semiconductor-based devices are needed.


  • Use GaN-based Hall Effect Sensors to monitor magnetic fields in motors due to substrate stability

  • Model failure modes and corollate them to new alloy generations at higher temperatures.


  • Measure the initial material electrical properties of Hall sensors fabricated at UARK and Stanford.
  • Subject samples to accelerated thermal aging with different temperature and time scales
  • Repeat electrical and material measurements and compare with initial.
  • Use electrical and material measurements to generate a representation of the reliability and ideal operating temperatures and lifetimes.

Key Results

  • Stanford AlGaN/GaN devices showed a steady increase in resistance during 450 C tests and leveled around 50 hours into accelerated aging tests
  • Stanford InAlN/GaN devices appeared stable through 48 hours at 450 C
  • UARK GaN appeared to have interdiffusion events


  • Smaller time scales at 200 C have overall stable device electrical properties.

  • Temperatures above 450 C result in physical changes which may impact contact reliability.

  • Contacts are the most likely part of the devices to fail.

Future Work

  • Subject newly designed devices to higher temperature environments and longer durations.

  • Measure interdiffusion events after failure.

  • Investigate effects of thermally aging samples in inert environments.