A p-layer on a surface layer of one of n.sup. drift layers is separated into a p-base-region and a floating p-region by a plurality of trenches. A first gate electrode is disposed on a side wall of the trench on the p-base-region side via a first insulation film, and a shield electrode is disposed on a side wall of the trench on the floating p-region side via a second insulation film. Between the first gate electrode conductively connected to a gate runner via a contact plug embedded in a first contact hole and the shield electrode conductively connected to an emitter electrode via a contact plug embedded in a second contact hole, an insulation film reaches from the front surface of the substrate to the bottom surface of the trench. Hence, the fabrication process can be shortened to provide a highly reliable semiconductor device with low switching loss.

Provided is a semiconductor device including: a front surface electrode provided above the semiconductor substrate; a trench contact portion at which the front surface electrode and the mesa portion are connected to each other in the transistor portion; and a front surface contact portion at which the front surface electrode and the mesa portion are connected to each other in the diode portion, where a lower end of the front surface contact portion is arranged above a lower end of the trench contact portion.

An object is to achieve an increase in gain by reducing a current collapse, and reducing Cgd and Rg. A semiconductor device according to the present invention includes a substrate; a first semiconductor layer disposed on the substrate and made of a Group III nitride semiconductor; a second semiconductor layer disposed on the first semiconductor layer and made of a Group III nitride semiconductor; a gate electrode, a source electrode, and a drain electrode disposed on the second semiconductor layer; a first field plate electrode disposed on the second semiconductor layer; and a second field plate electrode disposed on the first field plate electrode, in which the first field plate electrode and the second field plate electrode are disposed between the gate electrode and the drain electrode.

Apparatus and methods for providing variable regulated voltages are disclosed. Variable voltage control elements can adjust a regulated voltage provided by a single voltage regulator, thereby providing a variable regulated voltage. The regulated voltage can be used in a variety of applications, for example, as a bias voltage for a power amplifier.

A semiconductor device includes a semiconductor substrate having a first conductivity type. A gate structure is supported by a surface of the semiconductor substrate, and a current carrying region (e.g., a drain region of an LDMOS transistor) is disposed in the semiconductor substrate at the surface. The device further includes a drift region of a second, opposite conductivity type disposed in the semiconductor substrate at the surface. The drift region extends laterally from the current carrying region to the gate structure. The device further includes a buried region of the second conductivity type disposed in the semiconductor substrate below the current carrying region. The buried region is vertically aligned with the current carrying region, and a portion of the semiconductor substrate with the first conductivity type is present between the buried region and the current carrying region.

A substrate of the silicon on insulator type includes a semi-conducting film disposed on a buried insulating layer which is disposed on an unstressed silicon support substrate. The semi-conducting film includes a first film zone of tensile-stressed silicon and a second film zone of tensile-relaxed silicon. Openings through the buried insulating layer permit access to the unstressed silicon support substrate under the first and second film zones. An N channel transistor is formed from the first film zone and a P channel transistor is formed from the second film zone. The second film zone may comprise germanium enriched silicon forming a compressive-stressed region.

In one general aspect, a method of fabricating a power device can include preparing a semiconductor substrate of a first conductivity type, and forming a first Field Stop (FS) layer and a second FS layer.

An electric assembly includes a semiconductor switching device with a maximum breakdown voltage rating across two load terminals in an off-state. A clamping diode is electrically connected to the two load terminals and parallel to the switching device. A semiconductor body of the clamping diode is made of silicon carbide. An avalanche voltage of the clamping diode is lower than the maximum breakdown voltage rating of the switching device.

There is provided a power semiconductor device including: a first semiconductor region of a first conductivity type; second semiconductor regions formed in the first semiconductor region and being of a second conductivity type; a well region formed above the second semiconductor regions and being of the second conductivity type; and a source region formed in the well region and being of the first conductivity type, wherein the second semiconductor regions include 1 to n layers formed from a lower portion of the device extending a in a direction of height of the device, and in the case that the widest width of the of the second semiconductor region of the n.sup.th layer is P.sub.n, P.sub.1<P.sub.n (n2).

An insulated gate bipolar transistor (IGBT) manufacturing method comprises the following steps: providing a semiconductor substrate of a first conducting type, the semiconductor substrate having a first major surface and a second major surface (100); forming a field-stop layer of a second conducting type on the first major surface of the semiconductor substrate (200); growing an oxide layer on the field-stop layer (300); removing the oxide layer from the field-stop layer (400); forming an epitaxial layer on the field-stop layer from which the oxide layer has been removed; and then manufacturing an IGBT on the epitaxial layer (600). Before regular manufacturing of an IGBT, the surface defects of a substrate material are eliminated as many as possible before epitaxy is formed, and the quality of an epitaxial layer is improved, thereby improving the quality of the whole IGBT.