Reliability Study of GaN-Based Hall Sensors
Student: Alexis Krone
Degree: M.S., May 2021
Major Professor: Dr. David Huitink
Physical & Chemical Sensors
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.
- 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.
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.