Rated overload characteristics of IGBTs for low voltage and high voltage devices

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. While the trade off behaviour (on state voltage to tail charge) and the overall ruggedness (short circuit, positive TK in VCEsat, temperature independence in tail charge, etc.) is independent of voltage and current ratings, the switching characteristics of the lower voltage parts (VBr<2 kV) is different in handling to the high voltage transistors (VBr>2 kV). With the HE-EMCON diode and the new FS NPT IGBT up to 1700 V there is almost no limitation in the switching behaviour some considerations-a certain value in the external gate resistor has to be taken. High voltage parts usually have lower current density comparing to low voltage transistors so that the "dynamic" electrical field strength is more critical in high voltage diodes and IGBTs.