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 well of a first type of conductivity is formed in a semiconductor substrate, and wells of a second type of conductivity are formed in the well of the first type of conductivity at a distance from one another. By an implantation of dopants, a doped region of the second type of conductivity is formed in the well of the first type of conductivity between the wells of the second type of conductivity and at a distance from the wells of the second type of conductivity. Source/drain contacts are applied to the wells of the second type of conductivity, and a gate dielectric and a gate electrode are arranged above regions of the well of the first type of conductivity that are located between the wells of the second type of conductivity and the doped region of the second type of conductivity.

A semiconductor device having an n channel MISFET formed on an SOI substrate including a support substrate, an insulating layer formed on the support substrate and a silicon layer formed on the insulating layer has the following structure. An impurity region for threshold adjustment is provided in the support substrate of a gate electrode so that the silicon layer contains carbon. The threshold value can be adjusted by the semiconductor region for threshold adjustment in this manner. Further, by providing the silicon layer containing carbon, even when the impurity of the semiconductor region for threshold adjustment is diffused to the silicon layer across the insulating layer, the impurity is inactivated by the carbon implanted into the silicon layer. As a result, the fluctuation of the transistor characteristics, for example, the fluctuation of the threshold voltage of the MISFET can be reduced.

A method for fabricating field effect transistors using carbon doped silicon layers to substantially reduce the diffusion of a doped screen layer formed below a substantially undoped channel layer includes forming an in-situ epitaxial carbon doped silicon substrate that is doped to form the screen layer in the carbon doped silicon substrate and forming the substantially undoped silicon layer above the carbon doped silicon substrate. The method may include implanting carbon below the screen layer and forming a thin layer of in-situ epitaxial carbon doped silicon above the screen layer. The screen layer may be formed either in a silicon substrate layer or the carbon doped silicon substrate.

Occurrence of short-channel characteristics and parasitic capacitance of a MOSFET on a SOI substrate is prevented.

A sidewall having a stacked structure obtained by sequentially stacking a silicon oxide film and a nitride film is formed on a side wall of a gate electrode on the SOI substrate. Subsequently, after an epitaxial layer is formed beside the gate electrode, and then, the nitride film is removed. Then, an impurity is implanted into an upper surface of the semiconductor substrate with using the gate electrode and the epitaxial layer as a mask, so that a halo region is formed in only a region of the upper surface of the semiconductor substrate which is right below a vicinity of both ends of the gate electrode.

Occurrence of short-channel characteristics and parasitic capacitance of a MOSFET on a SOI substrate is prevented. A sidewall having a stacked structure obtained by sequentially stacking a silicon oxide film and a nitride film is formed on a side wall of a gate electrode on the SOI substrate. Subsequently, after an epitaxial layer is formed beside the gate electrode, and then, the nitride film is removed. Then, an impurity is implanted into an upper surface of the semiconductor substrate with using the gate electrode and the epitaxial layer as a mask, so that a halo region is formed in only a region of the upper surface of the semiconductor substrate which is right below a vicinity of both ends of the gate electrode.

The present invention provides a semiconductor device and a method of forming the same. The semiconductor device includes a substrate, a first transistor and a second transistor. The first transistor and the second transistor are disposed on the substrate. The first transistor includes a first channel and a first work function layer. The second transistor includes a second channel and a second work function layer, where the first channel and the second channel include different dopants, and the second work function layer and the first work function layer have a same conductive type and different thicknesses.

Integrated circuits including multiple gate devices with dual threshold voltages and methods for fabricating such integrated circuits are provided. An exemplary method for fabricating an integrated device includes providing a semiconductor fin structure overlying a semiconductor substrate. The semiconductor fin structure has a first sidewall, a second sidewall opposite the first sidewall, and an upper surface. The method includes forming a first gate along the first sidewall of the semiconductor fin structure with a first threshold voltage. Further, the method includes forming a second gate along the second sidewall of the semiconductor fin structure with a second threshold voltage different from the first threshold voltage.

Provided is a semiconductor device having improved performance. In a semiconductor substrate located in a memory cell region, a memory cell of a nonvolatile memory is formed while, in the semiconductor substrate located in a peripheral circuit region, a MISFET is formed. At this time, over the semiconductor substrate located in the memory cell region, a control gate electrode and a memory gate electrode each for the memory cell are formed first. Then, an insulating film is formed so as to cover the control gate electrode and the memory gate electrode. Subsequently, the upper surface of the insulating film is polished to be planarized. Thereafter, a conductive film for the gate electrode of the MISFET is formed and then patterned to form a gate electrode or a dummy gate electrode for the MISFET in the peripheral circuit region.

A method includes removing a top portion of a substrate after implantation of a punch through stopper into the substrate; epitaxially growing undoped material on the substrate, thereby forming a channel; filling a top portion of the channel with an intermediate implant forming a vertically bi-modal dopant distribution, with one doping concentration peak in the top portion of the channel and another doping concentration peak in the punch through stopper; and patterning fins into the channel and the punch though stopper to form a finFET structure.