Condition Monitoring of Power Modules for SiC and GaN Semiconductors by Piezoelectric Effect

Abstract:
Degradation of chip solder and bond wires due to thermal stress is the main cause for power modules to fail. In this paper a new approach for condition monitoring of power module health status regarding chip solder is presented. Piezoelectricity of SiC and GaN semiconductors can be used to electrically excite a power module chip at its mechanical eigenfrequencies. Since eigenfrequencies are highly sensitive to system changes, its measurement and analysis is examined to detect delamination in the chip solder. Delamination occurring at the center, as well as delamination emanating from the chip edges, both induce significant shift in eigenfrequency.