Single pulse safe operating area of trench power MOSFETs in automotive power integrated circuits

New generations of smart power integrated circuit, IC, technologies need to provide higher performance at lower costs than their predecessors. These conflicting goals have been met in recent years by reducing the feature sizes and by introducing novel device structures for the power MOSFETs. An example of such novel device structures are trench power MOSFETs. Due to their low specific on- resistance (on-resistance times area), Ron · A, their integration into smart power technologies has been an active field of development in recent years. With each technology generation, the power MOSFETs are exposed to growing stress conditions due to increased power densities and increased application requirements. As a result, power MOSFET biasing conditions approach more and more the physical limits which define the boundaries of their Safe Operating Area, SOA. Demanding application requirements are e. g. the short-circuit requirements for smart automotive switches. Under repetitive pulse stress, product reliability is usually limited by package or metallization. Under single-pulse stress, however, failures may occur due to the power MOSFET itself. Such single-pulse power device failure is associated with self-heating and thermal run-away defining the boundaries of the electro-thermal SOA. This work studies the SOA limits of trench power MOSFETs integrated in a smart power technology for automotive applications under single pulse destructive stress related to thermal run-away.