US Patent 7180106 Semiconductor device having enhanced di/dt tolerance and dV/dt tolerance

A semiconductor device has an enhanced di/dt tolerance and a dv/dt tolerance without increasing an ON resistance. An underpad base region is provided on a region in an upper main surface of a semiconductor substrate which is provided under a gate pad, and the underpad base region is not connected to a source electrode and is not coupled to a main base region connected to the source electrode. The underpad base region is brought into a floating state.