A double-gate-type static-induction thyristor

A double-gate-type static-induction thyristor (DG-SIThy) with a high blocking voltage and a high current rating has been fabricated. In this paper, a basic operational mechanism, a fabrication procedure, and the electrical characteristics of the DG-SIThy are described. In the DG-SIThy, both electron injection and hole injection are controlled by signals applied to two gale regions so that the DG-SIThy is capable of higher frequency operations than a single-gate SIThy. In the DG-SIThy, described here, both a cathode and a gate (first gate) regions have been fabricated on one side of a semiconductor wafer and both an anode and gate.(second gate) regions on another side. For realizing the DG-SIThy with a high blocking voltage and a high current rating, we have tried attentively to form a p-n junction on one side of the wafer without influencing the p-n junction on the other side, and have developed a new counter-doping technique for epitaxial growth and an improved package structure for a compression-mounted device. The DG-SIThy fabricated with these techniques has shown a for-Ward blocking voltage of 1000 V, an average current rating of 100 A, and a forward voltage drop of 1.44 V at the rated anode current. A turn-on time of 0.95 its and a turn-off time of 0.48 µs have been observed at the rated anode current and at anode voltages of 650 and 550 V, respectively. As already speculated, the DG-SIThy shows a higher switching speed and a lower forward drop than the single-gate SIThy.