An Improved Edge Termination Structure to Optimize 3.3kV IGBTs Ruggedness

An optimized edge termination structure by increasing the coverage rate of metal plates at termination area is presented for 3.3kV IGBTs. This structure indicates a better stability after 168 hours High temperature reverse bias (HTRB) experiment. The electric potential contours and the surface electric field distribution with the variation of oxide charge are analyzed through numerical simulation. It is realized that the optimized termination structure is less sensitive with oxide charge. Thus the surface electric field is more uniform at each ring location to weaken the electric field concentration. Therefore, the breakdown voltage of the optimized structure is more stable than the conventional structure, which is in good agreement with the experiment results.