Influence of Current Density on Power Cycling Test of Low Voltage MOSFETs in DC Body-Diode Mode and Switching MOSFET-Mode

Inhalt:
This paper presents the dependency of power cycling lifetime on current density for low voltage Si MOSFETs tested under DC body-diode mode and switched MOSFET mode. In body-diode test, lifetime is found to decrease more strongly with increasing current as compared to switched MOSFET mode. This can be attributed partly to a higher joule heating of the bond wire in DC mode than in switching mode, and partly to the current crowding due to negative temperature coefficient (NTC) of body-diode leading to severe heating at the bond feet. Influence of current crowding is further investigated by another DC test in inverse MOSFET mode at a low VGS (channel partially opened) so that VSD has a positive temperature coefficient. Infrared camera measurements and ANSYS simulations are also used to explain the test results.