Patent ID: 6091108
Filing Date: 2000-07-18
Classification: H01L

Abstract:
A semiconductor device of SiC comprising three terminals so that a high voltage can be maintained between two of said terminals in a blocking state of the device, said third terminal being used as a controlling electrode so that the device has a transistor action and is of the insulated gate type, the device further comprising two parts, each comprising one or more semiconductor layers of SiC, said parts being connected in series between said two terminals, one of the parts being a sub-semiconductor device adapted to control current flow in the on-state and capable to withstand only low voltages in the blocking state thereof and a second part being a voltage-limiting part capable to withstand high voltages in the blocking state of the device and adapted to protect said sub-semiconductor device by taking a major part of the voltage over the device in the blocking state thereof, the voltage limiting part being located at a distance from the sub-semiconductor device and comprising a plurality of buried regions of a first conductivity type buried in a layer of an opposite second conductivity type at a distance below said sub-semiconductor device, said buried regions being laterally spaced from each other and forming a grid, in the blocking state of the device regions between the buried regions become depleted to form a continuous layer of said first conductivity type and, by that, a pn-junction at a distance from said sub-semiconductor device taking a major part of the voltage drop over the device in a blocking state thereof, said buried regions being provided with contacts for giving said buried regions a fixed potential.