A bidirectional thyristor capable of improving (dv/dt)c capability includes first and second first-conductivity-type semiconductor layers; first and second second-conductivity-type semiconductor layers; a plurality of carrier emitting portions disposed on a third second-conductivity-type semiconductor layer; a fourth second-conductivity-type semiconductor layer; first and second electrodes; a gate electrode; and a passivation film. The plurality of carrier emitting portions are configured such that an opening is formed in the third second-conductivity-type semiconductor layer and the first first-conductivity-type semiconductor layer is located in the opening. In plan view, the carrier emitting portions are disposed between a position away from the gate electrode by a predetermined distance and an outer edge of the first electrode. The plurality of carrier emitting portions are disposed in contact with the outer edge of the first electrode which is in contact with a passivation film.

A vertical semiconductor triode includes a first layer of semiconductor material, the first layer including first and second surfaces, the first surface being in contact with a first electrode forming a Schottky contact.

A vertical semiconductor triode includes a first layer of semiconductor material, the first layer including first and second surfaces, the first surface being in contact with a first electrode forming a Schottky contact.