Abstract: A semiconductor device includes: a silicon substrate that includes a high-concentration layer containing first conductivity type impurities; a low-concentration layer formed on the high-concentration layer and containing first conductivity type impurities; a first electrode and a second electrode formed on the low-concentration layer; a vertical semiconductor element that allows current to flow between the second electrode and the high-concentration layer; and a first trench unit that realizes electric connection between the first electrode and the high-concentration layer. The first trench unit consists of first polysilicon containing first conductivity type impurities, and a diffusion layer configured to surround the first polysilicon in a plan view and to contain first conductivity type impurities. The first polysilicon is configured to reach the high-concentration layer by penetrating the low-concentration layer.

Abstract: A semiconductor device includes a second conductivity type back gate electrode formed within a body area, and electrically connected with the body area, and performs bidirectional current control in a direction from a drain area to a source area and in a direction from the source area to the drain area. A sheet resistance of the back gate electrode is lower than a sheet resistance of the body area. The source area and the back gate electrode are disposed apart from each other with a clearance sufficient for preventing a breakdown phenomenon caused between the source area and the back gate electrode when a maximum operation voltage is applied between the source area and the drain area.

Abstract: A semiconductor device includes: a silicon substrate that includes a high-concentration layer containing first conductivity type impurities; a low-concentration layer formed on the high-concentration layer and containing first conductivity type impurities; a first electrode and a second electrode formed on the low-concentration layer; a vertical semiconductor element that allows current to flow between the second electrode and the high-concentration layer; and a first trench unit that realizes electric connection between the first electrode and the high-concentration layer. The first trench unit consists of first polysilicon containing first conductivity type impurities, and a diffusion layer configured to surround the first polysilicon in a plan view and to contain first conductivity type impurities. The first polysilicon is configured to reach the high-concentration layer by penetrating the low-concentration layer.

Abstract: A semiconductor device includes a second conductivity type back gate electrode formed within a body area, and electrically connected with the body area, and performs bidirectional current control in a direction from a drain area to a source area and in a direction from the source area to the drain area. A sheet resistance of the back gate electrode is lower than a sheet resistance of the body area. The source area and the back gate electrode are disposed apart from each other with a clearance sufficient for preventing a breakdown phenomenon caused between the source area and the back gate electrode when a maximum operation voltage is applied between the source area and the drain area.

Abstract: An SOI semiconductor device includes at least an SOI substrate including an insulating film and a semiconductor layer formed on the insulating film; and an active semiconductor element formed on the semiconductor layer. The active semiconductor element is formed in an element formation region surrounded by an isolating region for isolating the semiconductor layer in a form of an island. A gettering layer containing a high concentration impurity is formed in a portion of the semiconductor layer excluding the element formation region in which the active semiconductor element is formed, and the gettering layer is not formed in the element formation region in which the active semiconductor element is formed.

Abstract: An SOI semiconductor device includes at least an SOI substrate including an insulating film and a semiconductor layer formed on the insulating film; and an active semiconductor element formed on the semiconductor layer. The active semiconductor element is formed in an element formation region surrounded by an isolating region for isolating the semiconductor layer in a form of an island. A gettering layer containing a high concentration impurity is formed in a portion of the semiconductor layer excluding the element formation region in which the active semiconductor element is formed, and the gettering layer is not formed in the element formation region in which the active semiconductor element is formed.

Abstract: In an SOI (Silicon On Insulator) semiconductor device, a first semiconductor layer overlies a semiconductor substrate so as to sandwich an insulating layer, and second and third semiconductor layers with a different conductivity type from the second semiconductor layer are formed on the surface of the first semiconductor layer. At the interface between the first semiconductor layer and the insulating layer, a fourth semiconductor layer with a different conductivity type from the first semiconductor layer is formed. The fourth semiconductor layer includes an impurity of larger than 3×1012/cm2 so as not to be completely depleted even though a reverse bias voltage is applied between the second and third semiconductor layers.

Abstract: In an SOI (Silicon On Insulator) semiconductor device, a first semiconductor layer overlies a semiconductor substrate so as to sandwich an insulating layer, and second and third semiconductor layers with a different conductivity type from the second semiconductor layer are formed on the surface of the first semiconductor layer. At the interface between the first semiconductor layer and the insulating layer, a fourth semiconductor layer with a different conductivity type from the first semiconductor layer is formed. The fourth semiconductor layer includes an impurity of larger than 3×1012/cm2 so as not to be completely depleted even though a reverse bias voltage is applied between the second and third semiconductor layers.