An experimental and numerical study on the forward biased SOA ofIGBTs |
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Authors: | Hagino H. Yamashita J. Uenishi A. Haruguchi H. |
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Affiliation: | Power Device Div., Mitsubishi Electr. Corp., Japan; |
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Abstract: | Thermal and electrical destructions of n-ch 600 V punchthrough type IGBTs in F.B.SOA are investigated by experiments and simulations, The cause of the thermal destruction is the thermal disappearance of built-in potential of p-n junction between the n+ emitter and the p base of the IGBT integral DMOSFET occurring at the critical temperature of ~650 K. Experiment and simulation results for the critical temperature show a good agreement. The cause of the electrical destruction is impact ionization at the n- drift/n+ buffer junction in addition to the n- drift/p base junctions. That triggers a positive feedback mechanism of increasing IGBT integral pnp transistor current which causes the device to lose gate controllability. The experimentally obtained critical power dissipation is ~2000 kW/cm2. This value is ten times greater than BJTs. It was also found that emitter ballast resistance (EBR) plays an important role in describing the F.B.SOA of IGBTs |
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