Optiswitch Technology Corporation

Tajchai Navapanich

David M Giorgi

A Break Over Diode ('BOD') device is a gate-less two terminal high power semiconductor switch in which transitions from a blocking state to a conducting state are triggered by a dV/dt pulse to the anode. The BOD device can be thought of as two cross-coupled PNP and NPN transistors, and includes both anode and cathode shorts which reduce the gain of the NPN and PNP transistors by shunting some current away from their bases directly to their emitters, thereby improving blocking. Moreover, the anode and cathode shorts in conjunction with the device blocking junction form PN diodes which are distributed throughout the bulk of the material and function as anti-parallel diodes to the base-emitter junctions of the PNP and NPN transistors, which enables the BOD device to handle a larger current reversal for a longer period of time. The P base layer may be made thin to decrease the voltage fall time from full blocking to full conduction, and the cathode and anode shorts may be provided in a honeycomb pattern.

Silicon break over diode

Semiconductor switches, such as thyristors, may be light activated by introducing the light into the switch via a groove having a sloped surface to receive the triggering light. The use of a sloped surface increases the surface path length between points of different electrical potential in the groove and, therefore, reduces the likelihood of electrical breakdown on the groove wall. In one particular embodiment, a light-activated thyristor includes a semiconductor anode layer, an n-base layer, a p-base layer and a semiconductor cathode layer disposed parallel to a thyristor plane. A thyristor axis lies perpendicular to the thyristor plane. A groove having a light refracting side wall extends into the thyristor from the anode layer. A portion of the light refracting side wall is disposed non-parallel to the thyristor plane and to the thyristor axis, and extends in the n-drift layer.

Growing community of inventors

San Diego, CA, United States of America

Tajchai Navapanich