Effect of the Collector Design on the IGBT Avalanche Ruggedness: A Comparative Analysis Between Punch-Through and Field-Stop Devices

In this paper, we investigate the effect of collector design on the onset and the extension of the negative differential resistance (NDR) region that develops in the blocking curves of field-stop (FS) and punch-through (PT) insulated gate bipolar transistors. Differences on the NDR extension and on its temperature behavior for the PT structures with respect to the FS ones are found, and their dependence from the collector design is explained. Subsequently, the dynamic filamentary current conduction mechanism is studied by means of 2-D electrothermal simulations on a wide area structure with many elementary cells on PT and FS devices. The differences between the two structures in terms of filament movement and its influence on the max temperature of the hot spot are then demonstrated to adversely affect the ruggedness of PT devices compared with the FS ones.