A symmetrically-bidirectional bipolar transistor circuit where the two base contact regions are clamped, through a low-voltage diode and a resistive element, to avoid bringing either emitter junction to forward bias. This avoids bipolar gain in the off state, and thereby avoids reduction of the withstand voltage due to bipolar gain.

A power device includes a substrate, a drift layer disposed on the substrate, a terminal region and an active region disposed in the drift layer, an electrode layer disposed on the active region, a Schottky contact layer disposed between the electrode layer and the active region, a passivation layer including a first portion that is disposed on the drift layer, and a second portion that is connected to the first portion and that has an end surface distal from the drift layer. The end surface of the second portion is flush with a top surface of the electrode layer distal from the drift layer. Another two power devices are also provided.

A power device includes a substrate, a drift layer disposed on the substrate, a terminal region and an active region disposed in the drift layer, an electrode layer disposed on the active region, a Schottky contact layer disposed between the electrode layer and the active region, a passivation layer including a first portion that is disposed on the drift layer, and a second portion that is connected to the first portion and that has an end surface distal from the drift layer. The end surface of the second portion is flush with a top surface of the electrode layer distal from the drift layer. Another two power devices are also provided.

An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal that is constituted of a hexagonal crystal and having a first main surface as a device surface facing a c-plane of the SiC monocrystal and has an off angle inclined with respect to the c-plane, a second main surface at a side opposite to the first main surface, and a side surface facing an a-plane of the SiC monocrystal and has an angle less than the off angle with respect to a normal to the first main surface when the normal is 0.

An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal that is constituted of a hexagonal crystal and having a first main surface as a device surface facing a c-plane of the SiC monocrystal and has an off angle inclined with respect to the c-plane, a second main surface at a side opposite to the first main surface, and a side surface facing an a-plane of the SiC monocrystal and has an angle less than the off angle with respect to a normal to the first main surface when the normal is 0.

An electronic device includes a silicon carbide layer having a first conductivity type and a main junction adjacent a surface of the silicon carbide layer, and a junction termination region at the surface of the silicon carbide layer adjacent the main junction. Charge in the junction termination region decreases with lateral distance from the main junction, and a maximum charge in the junction termination region may be less than about 210.sup.14 cm.sup.2.

The present invention provides a semiconductor device that prevents destruction due to an avalanche breakdown and that has a high tolerance against breakdown by configuring the device so as to have a punch-through breakdown function therein and such that the breakdown voltage of a punch-through breakdown is lower than an avalanche breakdown voltage so that an avalanche breakdown does not occur.

A semiconductor substrate has an element portion and a termination portion located on an outer side of the element portion. A first electrode layer is provided on a first surface of the semiconductor substrate. A second electrode layer is provided on a second surface of the semiconductor substrate in an upper portion of the element portion. An interlayer insulation film is provided on the second surface of the semiconductor substrate. The interlayer insulation film has: an element insulation portion that provides insulation between a part of the element portion of the semiconductor substrate and the second electrode layer; and a termination insulation portion covering a termination portion of the semiconductor substrate. The termination insulation portion includes a high dielectric constant film that is higher in dielectric constant than the element insulation portion.

A semiconductor element is provided which does not break down by avalanche current. A surge protection element includes: a semiconductor multi-layer comprising a nitride semiconductor; a first p-type semiconductor and a second p-type semiconductor which are disposed above the semiconductor multi-layer; a first electrode disposed above the first p-type semiconductor; and a second electrode disposed above the second p-type semiconductor.

A Schottky barrier diode element includes an n-type or p-type silicon (Si) substrate, an oxide semiconductor layer, and a Schottky electrode layer, the oxide semiconductor layer including either or both of a polycrystalline oxide that includes gallium (Ga) as the main component and an amorphous oxide that includes gallium (Ga) as the main component.