High power thyristors with 5 kV blocking voltage. Volume 1: Development of high voltage thyristors (4.5 kV) with good dynamic properties

Using neutron irradiated silicon with considerably lower spread in resistivity as compared to conventional doped silicon it was possible to produce power thyristors with breakdown-voltages between 3.5 kV and 5.5 kV. The thyristor pellets have a diameter of 50 mm. Maximum average on-state currents of 600-800 A can be reached with these elements. The dynamic properties of the thyristors could be improved to allow standard applications up to maximum repetitive voltages of 4.5 kV.