Provided is a semiconductor device comprising: a semiconductor substrate; a gate trench section that is provided from an upper surface to an inside of the semiconductor substrate and extends in a predetermined extending direction on the upper surface of the semiconductor substrate; a mesa section in contact to the gate trench section in an arrangement direction orthogonal the extending direction; and an interlayer dielectric film provided above the semiconductor substrate; wherein the interlayer dielectric film is provided above at least a part of the gate trench section in the arrangement direction; a contact hole through which the mesa section is exposed is provided to the interlayer dielectric film; and a width of the contact hole in the arrangement direction is equal to or greater than a width of the mesa section in the arrangement direction.

A terminal structure of a power device includes a substrate and a plurality of field limiting rings disposed on a first surface of the substrate. The substrate includes a drift layer and a doped layer. The doped layer is formed through diffusion inward from the first surface of the substrate. The doped layer and the drift layer are a first conductivity type, and an impurity concentration of the doped layer is greater than an impurity concentration of the drift layer. The field limiting rings are a second conductivity type. In the terminal structure, lateral diffusion of impurities in the field limiting rings is limited through a design of the doped layer.

A transistor device includes a semiconductor substrate having a first major surface, a cell field, and an edge termination region laterally surrounding the cell field. The cell field includes elongate trenches that extend from the first major surface into the semiconductor substrate and that are positioned substantially parallel to one another such that one or more inner elongate trenches are arranged between two outermost elongate trenches and elongate mesas, each elongate mesa being formed between neighbouring elongate trenches. The elongate mesas include a drift region, a body region on the drift region and a source region on the body region. In a top view, one or both of the outermost elongate trenches has a different contour from the one or more inner elongate trenches.

Semiconductor device including first semiconductor layer of a first conductivity type, second semiconductor layer of a second conductivity type at a surface of the first semiconductor layer, third semiconductor layer of the first conductivity type selectively provided at a surface of the second layer, and gate electrode embedded in a trench via a gate insulating film. The trench penetrates the second and third layers, and reaches the first layer. A thermal oxide film on the third layer has a thickness less than that of the gate insulating film. Also are an interlayer insulating film on the thermal oxide film, barrier metal on an inner surface of a contact hole selectively opened in the thermal oxide film and the interlayer insulating film, metal plug embedded in the contact hole on the barrier metal, and electrode electrically connected to the second and third layers via the barrier metal and the metal plug.

A semiconductor device includes first and second trenches, and a first layer provided therebetween, in a principal surface of a semiconductor substrate, a second layer in contact with and sandwiching the first trench with the first layer, a third layer provided under the second layer and in contact with the second layer and the first trench, a fourth layer provided under and in contact with the third layer but separated from the first trench, and a fifth layer provided in the principal surface and sandwiching the second trench with the first layer. The second and fourth layers are semiconductors of a first conductivity type, and the first, third, and fifth layers are semiconductors of a second conductivity type. A gate trench electrode is provided inside the first trench via the insulating film, and an emitter trench electrode is provided inside the second trench via the insulating film.

A power semiconductor device includes a semiconductor layer, a ladder-shaped trench recessed a specific depth from a surface of the semiconductor layer into the semiconductor layer and including a pair of lines having a first depth and a plurality of connectors connected between the pair of lines and having a second depth shallower than the first depth, a well region defined in the semiconductor layer between the pair of lines and between the plurality of connectors of the trench, a floating region defined in the semiconductor layer outside the pair of lines of the trench, a gate insulating layer disposed on an inner wall of the trench, and a gate electrode layer disposed on the gate insulating layer to fill the trench and including a first portion in which the pair of lines is filled and a second portion in which the plurality of connectors is filled. A depth of the second portion of the gate electrode layer is shallower than a depth of the first portion of the gate electrode layer.

A semiconductor device in which a transistor and a diode are formed on a common semiconductor substrate is provided. The semiconductor substrate includes a transistor region in which a transistor is formed and a diode region in which a diode is formed. At least one first electrode on a second main surface side of the transistor region and at least one second electrode on a second main surface side of the diode region are made of different materials.

A main semiconductor device element has first and second p.sup.+-type high-concentration regions that mitigate electric field applied to bottoms of trenches. The first p.sup.+-type high-concentration regions are provided separate from p-type base regions, face the bottoms of the trenches in a depth direction, and extend in a linear shape in a first direction that is a same direction in which the trenches extend. Between adjacent trenches of the trenches, the second p.sup.+-type high-concentration regions are provided scattered in the first direction, separate from the first p.sup.+-type high-concentration regions and the trenches and in contact with the p-type base regions. Between the second p.sup.+-type high-concentration regions adjacent to one another in the first direction, n-type current spreading regions or n.sup.+-type high-concentration regions having an impurity concentration higher than that of the n-type current spreading regions are provided in contact with the second p.sup.+-type high-concentration regions.

A transistor and a diode are formed on a common semiconductor substrate; the semiconductor substrate has a transistor region and an outer peripheral region surrounding it; the transistor region is divided into a plurality of channel regions and a plurality of non-channel regions by a plurality of gate electrodes each having a stripe shape; each of the plurality of non-channel regions has a first semiconductor layer, a second semiconductor layer, a third semiconductor layer, a fifth semiconductor layer, a first electrode, and a second electrode; the third semiconductor layer and the fifth semiconductor layer are electrically connected to the second electrode via a contact hole; and the fifth semiconductor layer is selectively provided not to be in contact with an impurity layer of a first conductivity type that is provided in the outer peripheral region and defines a boundary with a cell region.

All of four of built-in gate resistance trenches function as practical built-in gate resistance trenches. A first end portion of each of four of the built-in gate resistance trenches is electrically connected to a wiring side contact region of a gate wiring via a wiring contact. A second end portion of each of four of the built-in gate resistance trenches is electrically connected to a pad side contact region of a gate pad via a pad contact. In each of four of the built-in gate resistance trenches, a distance between the wiring contact and the pad contact is defined as an inter-contact distance.