Transit Time Oscillations as a Source of EMC Problems in Bipolar Power Devices

Transit time oscillations may occur in the turn-off phase of power devices and cause high-frequency oscillations. This paper investigates two mechanisms which lead to these oscillations: dynamic impact ionization transit time (IMPATT) oscillations and plasma extraction transit time (PETT) oscillations. Both lead to a deterioration of the EMC behavior and consequently they should be avoided.