Investigations on the ruggedness limit of 6.5 kV IGBT

The save operating area (SOA) of high voltage 6.5 kV IGBTs has been investigated. The ruggedness of the IGBT with planar cell structure is limited by the hole current density in the cell structure arriving from the avalanche generation under turn-off conditions. The impact of current density, V/sub cc/ and vertical IGBT structure on the ruggedness has been taken into account. With a modified cell design the avalanche generation can be reduced significantly. Simulations with a trench IGBT promises additional SOA improvement.