Provided is a semiconductor device including: a semiconductor substrate having a drift region of a first conductivity type; and a buffer region of the first conductivity type provided between the drift region and a lower surface of the semiconductor substrate and having a higher doping concentration than the drift region. The buffer region has two or more helium chemical concentration peaks arranged at different positions in a depth direction of the semiconductor substrate.

Plural sessions of proton irradiation are performed by differing ranges from a substrate rear surface side. After first to fourth n-type layers of differing depths are formed, the protons are activated. Next, helium is irradiated to a position deeper than the ranges of the proton irradiation from the substrate rear surface, introducing lattice defects. When the amount of lattice defects is adjusted by heat treatment, protons not activated in a fourth n-type layer are diffused, forming a fifth n-type layer contacting an anode side of the fourth n-type layer and having a carrier concentration distribution that decreases toward the anode side by a more gradual slope than that of the fourth n-type layer. The fifth n-type layer that includes protons and helium and the first to fourth n-type layers that include protons constitute an n-type FS layer. Thus, a semiconductor device having improved reliability and lower cost may be provided.

A semiconductor device includes a semiconductor part; first and second electrodes, the semiconductor part being provided between the first and second electrodes; a control electrode selectively provided between the semiconductor part and the second electrode; and a contacting part electrically connecting the semiconductor part and the second electrode. The semiconductor part includes a first layer of a first conductivity type, a second layer of a second conductivity type provided between the first layer and the second electrode, a third layer of the first conductivity type selectively provided between the second layer and the second electrode, and a fourth layer of the second conductivity type selectively provided between the second layer and the second electrode. The contacting part includes a first semiconductor portion of the first conductivity type contacting the third layer, and a second semiconductor portion of the second conductivity type contacting the fourth layer.

A silicon carbide semiconductor device includes a semiconductor substrate, a first semiconductor layer, a second semiconductor layer, a first semiconductor region, and a gate electrode. Protons are implanted in a first region spanning a predetermined distance from a surface of the semiconductor substrate facing toward the first semiconductor layer, in a second region spanning a predetermined distance from a surface of the first semiconductor layer on the second side of the first semiconductor layer facing toward the semiconductor substrate, in a third region spanning a predetermined distance from a surface of the first semiconductor layer on the first side of the first semiconductor layer facing toward the second semiconductor layer, and in a fourth region spanning a predetermined distance from a surface of the second semiconductor layer on the second side of the second semiconductor layer facing toward the first semiconductor layer.

A semiconductor device includes a semiconductor substrate, a transistor section, a diode section, and a boundary section provided between the transistor section and the diode section in the semiconductor substrate. The transistor section has gate trench portions which are provided from an upper surface of the semiconductor substrate to a position deeper than that of an emitter region, and to each of which a gate potential is applied. An upper-surface-side lifetime reduction region is provided on the upper surface side of the semiconductor substrate in the diode section and a partial region of the boundary section, and is not provided in a region that is overlapped with the gate trench portion in the transistor section in a surface parallel to the upper surface of the semiconductor substrate.

A semiconductor device includes: an n-doped drift region between first and second surfaces of a semiconductor body; a p-doped first region at the second surface; and an n-doped field stop region between the drift and first region. The field stop region includes first and second sub-regions with hydrogen related donors. A p-n junction separates the first region and first sub-region. A concentration of the hydrogen related donors, along a first vertical extent of the first sub-region, steadily increases from the pn-junction to a maximum value, and steadily decreases from the maximum value to a reference value at a first transition between the sub-regions. A second vertical extent of the second sub-region ends at a second transition to the drift region where the concentration of hydrogen related donors equals 10% of the reference value. A maximum concentration value in the second sub-region is at most 20% larger than the reference value.

Plural sessions of proton irradiation are performed by differing ranges from a substrate rear surface side. After first to fourth n-type layers of differing depths are formed, the protons are activated. Next, helium is irradiated to a position deeper than the ranges of the proton irradiation from the substrate rear surface, introducing lattice defects. When the amount of lattice defects is adjusted by heat treatment, protons not activated in a fourth n-type layer are diffused, forming a fifth n-type layer contacting an anode side of the fourth n-type layer and having a carrier concentration distribution that decreases toward the anode side by a more gradual slope than that of the fourth n-type layer. The fifth n-type layer that includes protons and helium and the first to fourth n-type layers that include protons constitute an n-type FS layer. Thus, a semiconductor device having improved reliability and lower cost may be provided.

A fabrication method for a semiconductor device includes measuring a thickness of a semiconductor substrate in which a bulk donor of a first conductivity type is entirely distributed, adjusting an implantation condition in accordance with the thickness of the semiconductor substrate and implanting hydrogen ions from a lower surface of the semiconductor substrate to an upper surface side of the semiconductor substrate, and annealing the semiconductor substrate and forming, in a passage region through which the hydrogen ions have passed, a first high concentration region of the first conductivity type in which a donor concentration is higher than a doping concentration of the bulk donor.

A silicon carbide semiconductor device includes an n-type drift layer disposed on an n-type silicon carbide substrate; an n-type current spreading layer disposed on a top surface of the drift layer, having a higher impurity concentration than the drift layer; a p-type base region disposed on a top surface of the current spreading layer; a p-type gate-bottom protection region located in the current spreading layer; a p-type base-bottom embedded region located in the current spreading layer, separated from the gate-bottom protection region to be in contact with a bottom surface of the base region; an insulated-gate electrode structure disposed in a trench penetrating the base region to reach the gate-bottom protection region, and a lower recombination region disposed in a lower portion of the drift layer, including crystal defects configured to recombine minority carriers injected into the drift layer.

A silicon carbide semiconductor device includes a semiconductor substrate, a first semiconductor layer, a second semiconductor layer, a first semiconductor region, and a gate electrode. Protons are implanted in a first region spanning a predetermined distance from a surface of the semiconductor substrate facing toward the first semiconductor layer, in a second region spanning a predetermined distance from a surface of the first semiconductor layer on the second side of the first semiconductor layer facing toward the semiconductor substrate, in a third region spanning a predetermined distance from a surface of the first semiconductor layer on the first side of the first semiconductor layer facing toward the second semiconductor layer, and in a fourth region spanning a predetermined distance from a surface of the second semiconductor layer on the second side of the second semiconductor layer facing toward the first semiconductor layer.