Overvoltage protection circuits are provided. In some embodiments, an overvoltage protection circuit includes a first diode made of a first semiconductor material having a bandgap width greater than that of silicon. A second diode is included and is electrically cross-coupled with the first diode. The second diode is made of a second semiconductor material different from the first semiconductor material.

A semiconductor device includes a semiconductor layer having a first surface and a second surface, an element structure formed on the first surface side of the semiconductor layer and including a first conductivity type first region and a second conductivity type second region in contact with the first region, a gate electrode opposing the second region with a gate insulating film therebetween, a first conductivity type third region formed in the semiconductor layer to be in contact with the second region, and a first electrode formed on the semiconductor layer and electrically connected to the first region and the second region, in which the element structure includes a first and a second element structure, the first element structure is separated from the second region in a direction along the first surface of the semiconductor layer, and includes a second conductivity type first column layer extending in a thickness direction.

A Freewheeling Diode of any kind (Fast Recovery Diode, Schottky Barrier Diode or other variants) is integrated with a Forced Extraction Device and in this way two entirely different functions—the Free-Wheeling function and the Forced Extraction function are combined in one device, simplifying the circuit and reducing the number of components. The FWD part of the integrated device is standard in the industry, but the Forced Extraction Device is made using a lateral or vertical PMOS with a votage capability between a control input and the output terminals that is as high or higher than the rating voltage of the Main Switch that will be used together with the FWD.

A Freewheeling Diode of any kind (Fast Recovery Diode, Schottky Barrier Diode or other variants) is integrated with a Forced Extraction Device and in this way two entirely different functions—the Free-Wheeling function and the Forced Extraction function are combined in one device, simplifying the circuit and reducing the number of components. The FWD part of the integrated device is standard in the industry, but the Forced Extraction Device is made using a lateral or vertical PMOS with a votage capability between a control input and the output terminals that is as high or higher than the rating voltage of the Main Switch that will be used together with the FWD.

A semiconductor device includes a conductive substrate, a conductive first joint portion arranged on the substrate, a SiC diode chip arranged on the first joint portion, a conductive second joint portion arranged on the SiC diode chip, and a transistor chip arranged on the second joint portion. The SiC diode chip includes a cathode pad arranged on one end and an anode pad arranged on the other end in the thickness direction. The cathode pad is joined to the substrate by the first joint portion. The transistor chip includes a drain electrode arranged on one end in the thickness direction. The anode pad is joined with the drain electrode by the second joint portion. The anode pad is arranged in a region enclosed by an outer edge of the SiC diode chip as viewed in a thickness direction of the substrate. The anode pad has an area larger than that of the transistor chip as viewed in the thickness direction of the substrate.

A nitride semiconductor device is provided that includes: a substrate; an n-type drift layer above the front surface of the substrate; a p-type base layer above the n-type drift layer; a gate opening in the base layer that reaches the drift layer; an n-type channel forming layer that covers the gate opening and has a channel region; a gate electrode above a section of the channel forming layer in the gate opening; an opening that is separated from the gate electrode and reaches the base layer; an opening formed in a bottom surface of said opening and reaching the drift layer; a source electrode covering the openings; and a drain electrode on the rear surface of the substrate.

A nitride semiconductor device is provided that includes: a substrate; an n-type drift layer above the front surface of the substrate; a p-type base layer above the n-type drift layer; a gate opening in the base layer that reaches the drift layer; an n-type channel forming layer that covers the gate opening and has a channel region; a gate electrode above a section of the channel forming layer in the gate opening; an opening that is separated from the gate electrode and reaches the base layer; an opening formed in a bottom surface of said opening and reaching the drift layer; a source electrode covering the openings; and a drain electrode on the rear surface of the substrate.

Provided is a semiconductor device including, a plurality of PN junction diodes each having a negative temperature characteristic and connected to each other in series; a Schottky barrier diode having a positive temperature characteristic and connected to the PN junction diodes in parallel; and a die pad on which at least one of the PN junction diodes and the Schottky barrier diode are mounted commonly.

Provided is a semiconductor device including, a plurality of PN junction diodes each having a negative temperature characteristic and connected to each other in series; a Schottky barrier diode having a positive temperature characteristic and connected to the PN junction diodes in parallel; and a die pad on which at least one of the PN junction diodes and the Schottky barrier diode are mounted commonly.

Provided is a semiconductor device including, a plurality of PN junction diodes each having a negative temperature characteristic and connected to each other in series; a plurality of resistance elements connected respectively to the PN junction diodes in parallel and connected to each other in series; and a Schottky barrier diode having a positive temperature characteristic and connected to the PN junction diodes in parallel.