Light Triggered Thyristor with a MOS amplifying gate: an example of functionally integrated vertical high voltage power device

A planar process for the fabrication of functionally integrated vertical high voltage switches is proposed. The process sequence and the results are presented for a light triggered thyristor with a MOS amplifying gate. This device consists in monolithic integration of a thyristor, a MOS transistor, a photodiode, a Zener diode and a depletion mode MOSFET. The high input impedance of the MOS gate allows the power device to be triggered with a very low photocurrent. This device is particularly well-suited for applications requiring a high galvanic insulation towards signal processing and control circuitry.