Provided is a semiconductor device, including: a drift region of a first conductivity type which is provided in a semiconductor substrate, and a buffer region of the first conductivity type which is provided between the drift region and a lower surface of the semiconductor substrate, and has three or more concentration peaks higher than a doping concentration of the drift region of the semiconductor substrate in a depth direction. Three or more of the concentration peaks includes a shallowest peak closest to the lower surface of the semiconductor substrate, a high concentration peak arranged at an upper side than the lower surface of the semiconductor substrate than the shallowest peak, and one or more low concentration peaks arranged at an upper side than the lower surface of the semiconductor substrate than the high concentration peak and of which the doping concentration is or less of the high concentration peak.

A semiconductor device includes: an FET structure that is formed next to a looped trench on a semiconductor substrate and that has an n.sup.+ emitter region and an n.sup. drain region facing each other in the depth direction of the looped trench across a p-type base region; a p-type floating region formed on the side of the looped trench opposite to the FET structure; and an emitter connecting part that is electrically connected to the n.sup.+ emitter region and a trench gate provided in the same trench, the emitter connecting part and the trench gate being insulated from each other by the looped trench. The trench gate faces the FET structure, and the emitter connecting part faces the p-type floating region, across an insulating film.

A semiconductor device includes: an IGBT section including a vertical IGBT; and a diode section arranged along the IGBT section and including a diode. The diode section includes a hole injection reduction layer having a first conductivity type and arranged in an upper layer portion of a drift layer, extending to a depth deeper than an anode region constituted by a second conductivity type region in the diode section, having an impurity concentration lower than an impurity concentration of the anode region and higher than an impurity concentration of the drift layer.

A low voltage transient voltage suppressing (TVS) device supported on a semiconductor substrate supporting an epitaxial layer to form a bottom-source metal oxide semiconductor field effect transistor (BS-MOSFET) that comprises a trench gate surrounded by a drain region encompassed in a body region disposed near a top surface of the semiconductor substrate. The drain region interfaces with the body region constituting a junction diode. The drain region on top of the epitaxial layer constituting a bipolar transistor with a top electrode disposed on the top surface of the semiconductor functioning as a drain/collector terminal and a bottom electrode disposed on a bottom surface of the semiconductor substrate functioning as a source/emitter electrode. The body regions further comprises a surface body contact region electrically connected to a body-to-source short-connection thus connecting the body region to the bottom electrode functioning as the source/emitter terminal.

A method for manufacturing a semiconductor device having an SiC-IGBT and an SiC-MOSFET in a single semiconductor chip, including forming a second conductive-type SiC base layer on a substrate, and selectively implanting first and second conductive-type impurities into surfaces of the substrate and base layer to form a collector region, a channel region in a surficial portion of the SiC base layer, and an emitter region in a surficial portion of the channel region, the emitter region serving also as a source region of the SiC-MOSFET.

An IGBT includes an n-type drift layer, a p-type base layer and an n-type emitter layer formed on an upper surface of the n-type drift layer, and a p-type collector layer on a lower surface of the n-type drift layer. A FWD includes the n-type drift layer, a p-type anode layer formed on the upper surface of the n-type drift layer and an n-type cathode layer formed on the lower surface of the n-type drift layer. A p-type well is formed on the upper surface of the n-type drift layer in a wiring region and a termination region. A wiring is formed on the p-type well in the wiring region. The p-type well has a higher impurity concentration and is deeper than the p-type anode layer. The p-type well is not formed directly above the n-type cathode layer and is separate from a region directly above the n-type cathode layer.

A semiconductor device includes: a plurality of trenches provided in an upper surface of a semiconductor substrate; trench electrodes each provided in a corresponding one of the trenches; a first semiconductor layer of a first conductivity type provided in a first range interposed between adjacent ones of the trenches; a second semiconductor layer of a second conductivity type; a third semiconductor layer of the first conductivity type; an interlayer insulation film provided on the upper surface of the semiconductor substrate and including a plurality of contact holes; a first conductor layer provided in each of the contact holes; and a surface electrode provided on the interlayer insulation film and connected to each of the first conductor layers.

A semiconductor device arranged between a source voltage (Vss) and a power voltage (Vdd) may include a first terminal coupled to the power voltage Vdd. The semiconductor device may also include a decoupling capacitor. The decoupling capacitor may include a semiconductor fin coupled to the first terminal, a dielectric layer on the semiconductor fin, and a gate on the dielectric layer. The semiconductor device may further include a second terminal. The second terminal may include a conductive gate resistor coupled in series with the gate of the decoupling capacitor. The second terminal may be coupled to the source voltage Vss via a first interconnect layer (M1).

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.

According to one embodiment, a semiconductor device includes a first and second electrode, a first, second, third and fourth semiconductor region, and a first intermediate metal film. The first region is provided above the first electrode and has a first impurity concentration. The second region is provided above the first region and has a second impurity concentration lower than the first impurity concentration. The third region is provided above the second region and has a third impurity concentration. The fourth region is provided above the second region and has a fourth impurity concentration lower than the third impurity concentration. The second electrode is provided above the third region and the fourth region and is in ohmic contact with the third region. The intermediate metal film is provided between the second electrode and the fourth region. The intermediate metal film forms Schottky junction with the fourth region.