Overload capability and dynamic behaviour of low and high voltage IGBT and ultra fast softswitching diode

By a vertical shrink of the NPT IGBT to a structure with a thin n base and a low doped field stop layer a new IGBT can be realized with drastically reduced overall losses. Especially the combination of the field stop concept with the trench transistor cell results in the almost ideal carrier concentration for a device with minimum on state voltage and lowest switching losses. This concept has been developed for IGBTs and diodes from 600 V up to 6.5 kV. This paper shows the save operation area behaviour requirements for switching characteristics for low voltage devices (600 V/1200 V) and high voltage devices (3.5 kV/6.5 kV). It will be discussed that the overall switching behaviour for inductive loads is determined by the diode and IGBT at equivalent positions. In particular at high voltage applications precautions have to be taken during turn off and turn on. During turn on the dynamic electrical field strength of the diode is important to observe and during the turn off the same situation occurs in the IGBT