Semiconductor devices including a stressor in a recess and methods of forming the semiconductor devices are provided. The methods may include forming a trench in an active region and the trench may include a notched portion of the active region. The methods may also include forming an embedded stressor in the trench. The embedded stressor may include a lower semiconductor layer and an upper semiconductor layer, which has a width narrower than a width of the lower semiconductor layer. A side of the upper semiconductor layer may not be aligned with a side of the lower semiconductor layer and an uppermost surface of the upper semiconductor layer may be higher than an uppermost surface of the active region.

A metal-oxide-semiconductor transistor includes a substrate, a gate insulating layer disposed on the surface of the substrate layer, a metal gate disposed on the gate insulating layer and having at least one plug hole, at least one dielectric plug disposed in the plug hole, and two diffusion regions disposed at two sides of the metal gate in the substrate. The metal gate is configured to operate under an operation voltage greater than 5 v.

According to an embodiment, a semiconductor device is provided. The device includes a second region having a greater curvature than a first region. The device includes an epitaxy layer of a first conductivity type, a well of a second conductivity type in the epitaxy layer, a drain in the epitaxy layer, a source in the well, and a bulk in the well and in contact with the source, the bulk having a greater area in the second region than in the first region.

A transistor having a narrow bandgap semiconductor source/drain region is described. The transistor includes a gate electrode formed on a gate dielectric layer formed on a silicon layer. A pair of source/drain regions are formed on opposite sides of the gate electrode wherein said pair of source/drain regions comprise a narrow bandgap semiconductor film formed in the silicon layer on opposite sides of the gate electrode.

Methods and apparatus for quantum point contacts. In an arrangement, a quantum point contact device includes at least one well region in a portion of a semiconductor substrate and doped to a first conductivity type; a gate structure disposed on a surface of the semiconductor substrate; the gate structure further comprising a quantum point contact formed in a constricted area, the constricted area having a width and a length arranged so that a maximum dimension is less than a predetermined distance equal to about 35 nanometers; a drain/source region in the well region doped to a second conductivity type opposite the first conductivity type; a source/drain region in the well region doped to the second conductivity type; a first and second lightly doped drain region in the at least one well region. Additional methods and apparatus are disclosed.

A method for fabricating a semiconductor device structure is shown. A gate dielectric layer is formed on a substrate. A portion of the gate dielectric layer, which is located on a part of the substrate in which an S/D region is to be formed, is removed. A gate electrode is formed on the remaining gate dielectric layer. A spacer is formed on the sidewall of the gate electrode and the sidewall of the gate dielectric layer. The S/D region is then formed in the part of the substrate beside the spacer.

The symmetric LDMOS transistor comprises a semiconductor substrate (1), a well (2) of a first type of conductivity in the substrate, and wells (3) of an opposite second type of conductivity. The wells (3) of the second type of conductivity are arranged at a distance from one another. Source/drain regions (4) are arranged in the wells of the second type of conductivity. A gate dielectric (7) is arranged on the substrate, and a gate electrode (8) on the gate dielectric. A doped region (10) of the second type of conductivity is arranged between the wells of the second type of conductivity at a distance from the wells. The gate electrode has a gap (9) above the doped region (10), and the gate electrode overlaps regions that are located between the wells (3) of the second type of conductivity and the doped region (10).

Semiconductor devices including a stressor in a recess and methods of forming the semiconductor devices are provided. The methods may include forming a trench in an active region and the trench may include a notched portion of the active region. The methods may also include forming an embedded stressor in the trench. The embedded stressor may include a lower semiconductor layer and an upper semiconductor layer, which has a width narrower than a width of the lower semiconductor layer. A side of the upper semiconductor layer may not be aligned with a side of the lower semiconductor layer and an uppermost surface of the upper semiconductor layer may be higher than an uppermost surface of the active region.

A transistor having a narrow bandgap semiconductor source/drain region is described. The transistor includes a gate electrode formed on a gate dielectric layer formed on a silicon layer. A pair of source/drain regions are formed on opposite sides of the gate electrode wherein said pair of source/drain regions comprise a narrow bandgap semiconductor film formed in the silicon layer on opposite sides of the gate electrode.

A semiconductor device in which sufficient stress can be applied to a channel region due to lattice constant differences.