Live Detection of Stressed High Density Power Transistors

Long-Term Project Goal: Macroscopy Modeling for Micorscopic Variation

The goal of the project of Dr. Charles Kim's group is to eventually develop an embedded real-time reliability monitoring system for a power electronics board, focused on vulnerable components by applying no-excitation impedance spectroscopy, which is to be developed.  The first step of the project is dedicated to characterize those vulnerable components with Temperature-Current behavior under diverse loading and operating condition, normal and stress.  The correlation between a distinct T-I characteristic and a vulnerable component is desired to be discovered.  The second step is to develop a no-excitation impedance spectroscopy and applying the method to the most vulnerable component in a power electronic boards.  When, in due course, the impedance spectroscopy methods are embedded, the in-situ monitoring would provide more details on the failure modes and mechanisms, stress activation energy, temperature acceleration factors with statistical and mathematical framework to extrapolate life times, failure rates, and defectivity of the vulnerable components.

Present Efforts: (1)Surface Temperature & Magnetic Field Strength Monitoring and (2) Complex Impedance Locus

This project develops an on-chip and on-board temperature distribution and current monitoring system for AlGaN/GaN Power HEMTs under different source and load conditions at various base and surface temperature. The monitoring system comprises of a IR temperature sensor and a GMR magnetic sensor. In addition the monitoring system is equipped with source and load condition tuning system which enables to put the chip or board into the non-linear operating state at various source and load conditions.  The monitoring system, combined together with the temperature distribution map and the current/hall measurement, would produce the electro-thermal characteristics of the chip or board under the impact of different drives and loads.   Most vulnerable components in GaN and GaN-power electronic devices are expected to be found and discovered though this sensing and diagnostics project.    It is hoped it could also be able to measure the temperature-current relationship during the switching transition under stress-testing.

Students: Ayotunde Odejayi, Ikemefuna Uba, Derrick Anang, Bibek Ramdam, and Shmar Christian