A semiconductor device includes a first MOS transistor and a second MOS transistor of a second conductivity type. The first MOS transistor includes a first main electrode connected to a first potential and a second main electrode connected to a second potential. The second MOS transistor includes a first main electrode connected to a control electrode of the first MOS transistor and a second main electrode connected to the second potential. The control electrodes of the first and second MOS transistors are connected in common. The first and second MOS transistors are formed on a common wide bandgap semiconductor substrate. In the first MOS transistor, a main current flows in a direction perpendicular to a main surface of the wide bandgap semiconductor substrate. In the second MOS transistor, a main current flows in a direction parallel to the main surface of the wide bandgap semiconductor substrate.

A semiconductor device includes a semiconductor chip formed with an SiC-IGBT including an SiC semiconductor layer, a first conductive-type collector region formed such that the collector region is exposed on a second surface of the SiC semiconductor layer, a second conductive-type base region formed such that the base region contacts the collector region, a first conductive-type channel region formed such that the channel region contacts the base region, a second conductive-type emitter region formed such that the emitter region contacts the channel region to define a portion of a first surface of the SiC semiconductor layer, a collector electrode connected to the collector region, and an emitter electrode connected to the emitter region. A MOSFET of the device is connected in parallel to the SiC-IGBT, and includes a second conductive-type source region electrically connected to the emitter electrode and a second conductive-type drain region electrically connected to the collector electrode.

A semiconductor device includes a first silicon carbide semiconductor layer, a source including a source pad and a source wiring, a gate including a gate pad and a gate wiring, first unit cells disposed in a first element region, and second unit cells disposed in a second element region. In a plan view, the first and second element regions are adjacent to each other with the gate wiring between the first and second element regions. A first electrode including the gate electrode of each first unit cell is disposed in the first element region and electrically connected to the gate. A second electrode including the gate electrode of each second unit cell is disposed in the second element region and not electrically connected to the gate. The first and second electrodes are separated below the gate wiring.

An SiC semiconductor device has a p type region including a low concentration region and a high concentration region filled in a trench formed in a cell region. A p type column is provided by the low concentration region, and a p.sup.+ type deep layer is provided by the high concentration region. Thus, since a SJ structure can be made by the p type column and the n type column provided by the n type drift layer, an on-state resistance can be reduced. As a drain potential can be blocked by the p.sup.+ type deep layer, at turnoff, an electric field applied to the gate insulation film can be alleviated and thus breakage of the gate insulation film can be restricted. Therefore, the SiC semiconductor device can realize the reduction of the on-state resistance and the restriction of breakage of the gate insulation film.

A semiconductor device includes a first transistor having a first conductivity type SiC layer, a second conductivity type SiC well region, a first conductivity type SiC first source region, a first conductivity type SiC first drain region, and a first gate electrode provided on the well region sandwiched between the first source region and the first drain region. The device includes a second transistor having a second conductivity type SiC second source region, a second conductivity type SiC second drain region provided on the SiC layer, and a second gate electrode provided on the SiC layer sandwiched between the second source region and the second drain region. There is an angle between a direction of a channel forming portion of first transistor and that of the second transistor. The device includes an element isolation region having a bottom positioned in the SiC layer.

A multi-cell MOSFET device including a MOSFET cell with an integrated Schottky diode is provided. The MOSFET includes n-type source regions formed in p-type well regions which are formed in an n-type drift layer. A p-type body contact region is formed on the periphery of the MOSFET. The source metallization of the device forms a Schottky contact with an n-type semiconductor region adjacent the p-type body contact region of the device. Vias can be formed through a dielectric material covering the source ohmic contacts and/or Schottky region of the device and the source metallization can be formed in the vias. The n-type semiconductor region forming the Schottky contact and/or the n-type source regions can be a single continuous region or a plurality of discontinuous regions alternating with discontinuous p-type body contact regions. The device can be a SiC device. Methods of making the device are also provided.

In a silicon carbide semiconductor device, a trench penetrates a source region and a first gate region and reaches a drift layer. On an inner wall of the trench, a channel layer of a first conductivity-type is formed by epitaxial growth. On the channel layer, a second gate region of a second conductivity-type is formed. A first depressed portion is formed at an end portion of the trench to a position deeper than a thickness of the source region so as to remove the source region at the end portion of the trench. A corner portion of the first depressed portion is covered by a second conductivity-type layer.

A method for fabricating field effect transistors using carbon doped silicon layers to substantially reduce the diffusion of a doped screen layer formed below a substantially undoped channel layer includes forming an in-situ epitaxial carbon doped silicon substrate that is doped to form the screen layer in the carbon doped silicon substrate and forming the substantially undoped silicon layer above the carbon doped silicon substrate. The method may include implanting carbon below the screen layer and forming a thin layer of in-situ epitaxial carbon doped silicon above the screen layer. The screen layer may be formed either in a silicon substrate layer or the carbon doped silicon substrate.

A semiconductor device of an embodiment includes a SiC layer having a surface inclined with respect to a {000-1} face at an angle of 0 to 10 or a surface a normal line direction of which is inclined with respect to a <000-1> direction at an angle of 80 to 90, a gate electrode, an insulating layer at least a part of which is provided between the surface and the gate electrode, and a region, at least apart of which is provided between the surface and the insulating layer, including a bond between carbon and carbon.

Provided are a silicon carbide semiconductor device that is capable of preventing breakdown voltage degradation in the edge termination structure and a method of manufacturing the same.

The p-type regions 31, 32 and the p-type region 33, which serves as an electric field relaxation region and is connected to the first p-type base regions 10, are positioned under the step-like portion 40, and the bottom surfaces of the p-type regions 31, 32, 33 are substantially flatly connected to the bottom surface of the first p-type base regions 10.

The first base regions have an impurity concentration of 410.sup.17 cm.sup.3 or higher. The p-type region 33 is designed to have a lower impurity concentration than the first base regions 10 and higher than the p-type regions 31, 32. In this way, the breakdown voltage degradation in the edge termination structure 102 can be prevented.