There is provided a trench-gate type semiconductor device that can prevent breakdown of a gate insulating film caused by a displacement current flowing into a protective diffusion layer at a portion of a trench underlying a gate electrode at a turn-off time and simultaneously improves a current density by narrowing a cell pitch. The semiconductor device has a gate electrode 7 embedded into a trench 5 penetrating a base region 3. The gate electrode 7 is disposed into a lattice shape in a planar view, and a protective diffusion layer 13 is formed in a drift layer 2a at the portion underlying thereof. At least one of blocks divided by the gate electrode 7 is a protective contact region 20 on which the trench 5 is entirely formed. A protective contact 21 for connecting the protective diffusion layer 13 at a bottom portion of the trench 5 and a source electrode 9 is disposed on the protective contact region 20.

A semiconductor device includes a first IGBT cell having a second-type doped drift zone and a desaturation semiconductor structure for desaturating a charge carrier concentration in the first IGBT cell. The desaturation semiconductor structure includes a first-type doped region forming a pn-junction with the drift zone and two trenches arranged in the first-type doped region and arranged beside the first IGBT cell in a lateral direction. The two trenches confine a mesa region including a first-type doped desaturation channel region and a first-type doped body region at least in the lateral direction. The desaturation channel region and the body region adjoin each other, and the desaturation channel region is a depletable region.

An SOI wafer contains a compressively stressed buried insulator structure. In one example, the stressed buried insulator (BOX) may be formed on a host wafer by forming silicon oxide, silicon nitride and silicon oxide layers so that the silicon nitride layer is compressively stressed. Wafer bonding provides the surface silicon layer over the stressed insulator layer. Preferred implementations of the invention form MOS transistors by etching isolation trenches into a preferred SOI substrate having a stressed BOX structure to define transistor active areas on the surface of the SOI substrate. Most preferably the trenches are formed deep enough to penetrate through the stressed BOX structure and some distance into the underlying silicon portion of the substrate. The overlying silicon active regions will have tensile stress induced due to elastic edge relaxation.

In one implementation, a reduced gate charge field-effect transistor (FET) includes a drift region situated over a drain, a body situated over the drift region, and source diffusions formed in the body. The source diffusions are adjacent a gate trench extending through the body into the drift region and having a dielectric liner and a gate electrode situated therein. The dielectric liner includes an upper segment and a lower segment, the upper segment extending to at least a depth of the source diffusions and being significantly thicker than the lower segment.

Approaches for altering the threshold voltage (e.g., to zero threshold voltage) in a fin-type field effect transistor (FinFET) device are provided. In embodiments of the invention, a first N+ region and a second N+ region are formed on a finned substrate that has a p-well construction. A region of the finned substrate located between the first N+ region and the second N+ region is doped with a negative implant species to form an n-well. The size and/or composition of this n-well region can be adjusted in view of the existing p-well construction of the substrate device to change the threshold voltage of the FinFET device (e.g., to yield a zero threshold voltage FinFET device).

A transistor and a method for forming the transistor are provided. The method includes performing at least one implantation operation in the transistor channel area, then forming a silicon carbide/silicon composite film over the implanted area prior to introducing further dopant impurities. A halo implantation operation with a low tilt angle is used to form areas of high dopant concentration at edges of the transistor channel to alleviate short channel effects. The transistor structure includes a reduced dopant impurity concentration at the substrate interface with the gate dielectric and a peak concentration about 10-50 nm below the surface. The dopant profile has high dopant impurity concentration areas at opposed ends of the transistor channel.

A semiconductor structure includes first, second, and third transistor elements each having a first screening region concurrently formed therein. A second screening region is formed in the second and third transistor elements such that there is at least one characteristic of the screening region in the second transistor element that is different than the second screening region in the third transistor element. Different characteristics include doping concentration and depth of implant. In addition, a different characteristic may be achieved by concurrently implanting the second screening region in the second and third transistor element followed by implanting an additional dopant into the second screening region of the third transistor element

A MOSFET disposed between shallow trench isolation (STI) structures includes an epitaxial silicon layer formed over a substrate surface and extending over inwardly extending ledges of the STI structures. The gate width of the MOSFET is therefore the width of the epitaxial silicon layer and greater than the width of the original substrate surface between the STI structures. The epitaxial silicon layer is formed over the previously doped channel and is undoped upon deposition. A thermal activation operation may be used to drive dopant impurities into the transistor channel region occupied by the epitaxial silicon layer but the dopant concentration at the channel location where the epitaxial silicon layer intersects with the gate dielectric, is minimized.

The present invention relates to a junction field effect transistor. The junction field effect transistor comprises a substrate (10), a buried layer in the substrate, a first well region (32) and a second well region (34) that are on the buried layer, a source lead-out region (50), a drain lead-out region (60), and a first gate lead-out region (42) that are in the first well region (32), and a second gate lead-out region (44) in the second well region (34). A Schottky junction interface (70) is disposed on the surface of the first well region (32). The Schottky junction interface (70) is located between the first gate lead-out region (42) and the drain lead-out region (60), and is isolated from the first gate lead-out region (42) and the drain lead-out region (60) by means of isolation structures. The present invention also relates to a manufacturing method for a junction field effect transistor.

A semiconductor device includes a base dielectric layer, a semiconductor substrate layer disposed on the base dielectric layer, and a transistor disposed in the semiconductor substrate layer. The transistor includes a gate dielectric layer disposed on the semiconductor substrate layer, a gate electrode disposed on the gate dielectric layer, source and drain electrodes disposed within the semiconductor substrate layer on opposite sides of the gate electrode, an undoped channel region, a base dopant region, and a threshold voltage setting region. The undoped channel region, base dopant region, and threshold voltage setting region are disposed within the semiconductor substrate layer. The undoped channel region is disposed between the source electrode and the drain electrode, and the base dopant region and the threshold voltage setting region extend beneath the source electrode and the drain electrode. The threshold voltage setting region is disposed between the undoped channel region and the base dopant region.