Abstract: A bipolar transistor having at least a low doped drift layer (14) of crystalline SiC comprises at least one first layer (13) of a semi-conductor material having a wider energy gap between the conduction band and the valence band than an adjacent layer (14) of SiC.

Abstract: A Schottky diode of SiC has a substrate layer, a drift layer and emitter layer regions formed in the drift layer. A metal layer makes an ohmic contact to the emitter layer regions and Schottky contact to the drift layer. A depletion of the drift layer region between two adjacent emitter layer regions is allowed in the blocking state of the diode making the two adjacent p-type emitter layer regions form a continuous depleted region therebetween in this state.

Abstract: A semiconductor device of SiC is adapted to hold high voltages in the blocking state thereof. The device comprises two parts (1, 2) each comprising one or more semiconductor layers of SiC and connected in series between two opposite terminals of the device, namely a sub-semiconductor device (1) able to withstand only low voltages in the blocking state thereof and a voltage-limiting part (2) able 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.

Abstract: A method and a device for controlling a switching operation consisting of a turn on or a turn off operation in a voltage controlled power transistor is provided. At least one current source is arranged at the control electrode of the power transistor. The at least one current source controls the recharging of at least one of the capacitances which occurs between the control electrode of the power transistor and the main electrode of the power transistor to determine the time rate of change of at least one of the voltage and current.

Abstract: A power supply apparatus for a drive unit in a high voltage converter circuit, the circuit has a plurality of power semiconductors connected in series. Each power semiconductor is connected to a drive unit for turning the power semiconductor on and off. The power supply apparatus consists of a capacitor and a regulator connected in parallel with the power semiconductor. The capacitor is connected to the drive unit and stores sufficient energy for power supply of the drive unit. The regulator regulates the voltage across the capacitor.

Abstract: A method and a device for control of a switching operation consisting of a turn-on or turn-off operation in a voltage-controlled power transistor (T1), wherein at least one current source (S1, S2) is arranged at the control electrode (G) of the power transistor for controlling the recharging of at least one of the capacitances which occurs between the control electrode (G) of the power transistor and the main electrodes (C, E) of the power transistor and thus to determine the time rate of change of at least one of the quantities voltage and current.

Abstract: In a method for producing a channel region layer in a SiC-layer for providing a voltage-controlled semiconductor device a layer of silicon being one of a) polycrystalline and b) amorphous is applied on top of the SiC-layer, an aperture is etched in the silicon layer extending to the SiC-layer, a surface layer of a certain thickness of the silicon layer is oxidized, and the lateral extension of the channel region layer is determined by removing the oxidized layer and carrying out a further implantation into the area exposed by the so formed enlarged aperture.

Abstract: A converter circuit has at least one switching device and a SiC diode arranged to be conducting when the device is turned off and reverse-biased when the device is turned on.