A method for forming a semiconductor device comprises forming a first buffer layer with a first melting point on a substrate. A second buffer layer is formed on the first buffer layer. The second buffer layer has a second melting point that is greater than the first melting point. Annealing process is performed that increases a temperature of the first buffer layer such that the first buffer layer partially liquefies and causes a strain in the second buffer layer to be substantially reduced.

A semiconductor device includes a silicon substrate, a fin shaped structure and a shallow trench isolation. The fin shaped structure includes a top portion which protrudes from a bottom surface of the fin shaped structure and the fin shaped structure is directly disposed on the silicon substrate. The bottom surface of the fin shaped structure covers an entire top surface of the silicon substrate. The fin shaped structure further includes a silicon germanium (SiGe) layer extending within the fin shaped structure and occupying the whole top portion of the shaped structure. The fin shaped structure is a semiconductor fin shaped structure, and the material of the silicon substrate is different from the material of the silicon germanium layer The shallow trench isolation is disposed on the top portion and the bottom surface of the fin shaped structure.

In a method for manufacturing a semiconductor device, a fin structure including a first semiconductor layer, an oxide layer disposed over the first semiconductor layer and a second semiconductor layer disposed over the oxide layer is formed. An isolation insulating layer is formed so that the second semiconductor layer of the fin structure protrudes from the isolation insulating layer while the oxide layer and the first semiconductor layer are embedded in the isolation insulating layer. A third semiconductor layer is formed on the exposed second semiconductor layer so as to form a channel.

A method for forming a semiconductor device includes forming a fin structure on a substrate, forming a shallow trench isolation region adjacent the fin structure so that an upper portion of the fin structure is exposed, forming a dummy gate over the exposed fin structure, forming an interlayer dielectric layer around the dummy gate, removing the dummy gate to expose the fin structure, and after removing the dummy gate, introducing a strain into a crystalline structure of the exposed fin structure.

Transistor structures having channel regions comprising alternating layers of compressively and tensilely strained epitaxial materials are provided. The alternating epitaxial layers can form channel regions in single and multigate transistor structures. In alternate embodiments, one of the two alternating layers is selectively etched away to form nanoribbons or nanowires of the remaining material. The resulting strained nanoribbons or nanowires form the channel regions of transistor structures. Also provided are computing devices comprising transistors comprising channel regions comprised of alternating compressively and tensilely strained epitaxial layers and computing devices comprising transistors comprising channel regions comprised of strained nanoribbons or nanowires.

The benefits of strained semiconductors are combined with silicon-on-insulator approaches to substrate and device fabrication. A structure includes a relaxed substrate including a bulk material, a strained layer directly on the relaxed substrate, where a strain of the strained layer is not induced by the relaxed substrate, and a transistor formed on the strained layer.

A device includes a substrate and insulation regions over a portion of the substrate. A first semiconductor region is between the insulation regions and having a first conduction band. A second semiconductor region is over and adjoining the first semiconductor region, wherein the second semiconductor region includes an upper portion higher than top surfaces of the insulation regions to form a semiconductor fin. The second semiconductor region also includes a wide portion and a narrow portion over the wide portion, wherein the narrow portion is narrower than the wide portion. The semiconductor fin has a tensile strain and has a second conduction band lower than the first conduction band. A third semiconductor region is over and adjoining a top surface and sidewalls of the semiconductor fin, wherein the third semiconductor region has a third conduction band higher than the second conduction band.

A semiconductor is provided that includes an nFET gate structure straddling over a first nanowire stack and a portion of a first SiGe layer having a first Ge content. The first nanowire stack comprises alternating layers of a tensily strained silicon layer, and a second SiGe layer having a second Ge content that is greater than the first Ge content and being compressively strained. Portions of the tensily strained silicon layers extend beyond sidewalls surfaces of the nFET gate structure and are suspended. The structure further includes a pFET gate structure straddling over a second nanowire stack and another portion of the first SiGe layer. The second nanowire stack comprises alternating layers of the tensily strained silicon layer, and the second SiGe layer. Portions of the second SiGe layers extend beyond sidewalls surfaces of the pFET gate structure and are suspended.

A method and a device made according to the method. The method comprises providing a substrate including a first material, and providing a fin including a second material, the fin being disposed on the substrate and having a device active portion, the first material and the second material presenting a lattice mismatch between respective crystalline structures thereof. Providing the fin includes providing a biaxially strained film including the second material on the substrate; and removing parts of the biaxially strained film to form a substantially uniaxially strained fin therefrom.

A semiconductor structure can include a substrate and a substrate layer. The substrate can be formed of silicon and the substrate layer can be formed of silicon germanium. Above the substrate and under the substrate layer there can be provided a multilayer substructure. The multilayer substructure can include a first layer and a second layer. The first layer can be formed of a first material and the second layer can be formed of second material. A method can include forming a multilayer substructure on a substrate, annealing the multilayer substructure, and forming a substrate layer on the multilayer substructure.