Abstract: A semiconductor device according to an example embodiment of the present inventive concept includes a substrate having a first region and a second region horizontally separate from the first region; a first gate line in the first region, the first gate line including a first lower work function layer and a first upper work function layer disposed on the first lower work function layer; and a second gate line including a second lower work function layer in the second region, the second gate line having a width in a first, horizontal direction equal to or narrower than a width of the first gate line in the first direction, wherein an uppermost end of the first upper work function layer and an uppermost end of the second lower work function layer are each located at a vertical level higher than an uppermost end of the first lower work function layer with respect to a second direction perpendicular to the first direction.

Abstract: A semiconductor device according to an example embodiment of the present inventive concept includes a substrate having a first region and a second region horizontally separate from the first region; a first gate line in the first region, the first gate line including a first lower work function layer and a first upper work function layer disposed on the first lower work function layer; and a second gate line including a second lower work function layer in the second region, the second gate line having a width in a first, horizontal direction equal to or narrower than a width of the first gate line in the first direction, wherein an uppermost end of the first upper work function layer and an uppermost end of the second lower work function layer are each located at a vertical level higher than an uppermost end of the first lower work function layer with respect to a second direction perpendicular to the first direction.

Abstract: Semiconductor devices are provided. A semiconductor device includes a substrate including first through fourth areas. Moreover, first through fourth gate insulating layers are on the first through fourth areas, respectively. Amounts of work function control materials in the first through fourth gate insulating layers, nitrogen concentrations in the first through fourth gate insulating layers, and/or thicknesses of the first through fourth gate insulating layers vary among the first through fourth gate insulating layers. Methods for fabricating semiconductor devices are also provided.

Abstract: Semiconductor devices are provided. A semiconductor device includes a substrate including first through fourth areas. Moreover, first through fourth gate insulating layers are on the first through fourth areas, respectively. Amounts of work function control materials in the first through fourth gate insulating layers, nitrogen concentrations in the first through fourth gate insulating layers, and/or thicknesses of the first through fourth gate insulating layers vary among the first through fourth gate insulating layers. Methods for fabricating semiconductor devices are also provided.

Abstract: Provided are methods for fabricating a semiconductor device. A gate dielectric layer is formed on a substrate including first through third regions. A first functional layer is formed on only the first region of the first through third regions. A second functional layer is formed on only the first and second regions of the first through third regions. A threshold voltage adjustment layer is formed on the first through third regions. The threshold voltage adjustment layer includes a work function adjustment material. The work function adjustment material is diffused into the gate dielectric layer by performing a heat treatment process with respect to the substrate.

Abstract: Semiconductor devices are provided. A semiconductor device includes a substrate including first through fourth areas. Moreover, first through fourth gate insulating layers are on the first through fourth areas, respectively. Amounts of work function control materials in the first through fourth gate insulating layers, nitrogen concentrations in the first through fourth gate insulating layers, and/or thicknesses of the first through fourth gate insulating layers vary among the first through fourth gate insulating layers. Methods for fabricating semiconductor devices are also provided.

Abstract: Provided are methods for fabricating a semiconductor device. A gate dielectric layer is formed on a substrate including first through third regions. A first functional layer is formed on only the first region of the first through third regions. A second functional layer is formed on only the first and second regions of the first through third regions. A threshold voltage adjustment layer is formed on the first through third regions. The threshold voltage adjustment layer includes a work function adjustment material. The work function adjustment material is diffused into the gate dielectric layer by performing a heat treatment process with respect to the substrate.