Monolithically integrated power MOSFET and Schottky diode with improved reverse recovery characteristics

A power DMOSFET structure with a monolithically integrated Schottky diode located under the source contact pad is described. In this structure the source contact metallization step is also used to fabricate an epitaxial drift region Schottky diode in parallel with the parasitic body p-n junction diode of the power MOSFET. Such a structure results in significantly improved internal diode switching characteristics with no degradation in the on-state resistance and drain-source breakdown voltage. The integral power MOSFET technology was used to fabricate 30- and 45-V vertical power DMOSFETs with a reduction in peak reverse current and stored charge of more than 25% as compared to a conventional power DMOSFET. The Schottky diode consumed less than 15% of the active transistor area