An integrated circuit structure includes a gate stack over a semiconductor substrate, and a silicon germanium region extending into the semiconductor substrate and adjacent to the gate stack. The silicon germanium region has a top surface, with a center portion of the top surface recessed from edge portions of the top surface to form a recess. The edge portions are on opposite sides of the center portion.

Embodiments of mechanisms for epitaxially growing one or more doped silicon-containing materials to form source and drain regions of finFET devices are provided in this disclosure. The dopants in the one or more doped silicon-containing materials can be driven into the neighboring lightly-doped-drain (LDD) regions by thermal anneal to dope the regions. The epitaxially growing process uses a cyclical deposition/deposition/etch (CDDE) process. In each cycle of the CDDE process, a first and a second doped materials are formed and a following etch removes most of the second doped material. The first doped material has a higher dopant concentration than the second material and is protected from the etching process by the second doped material. The CDDE process enables forming a highly doped silicon-containing material.

A method for fabricating a semiconductor device having a substantially undoped channel region includes providing a substrate having a fin extending from the substrate. An in-situ doped layer is formed on the fin. By way of example, the in-situ doped layer may include an in-situ doped well region formed by an epitaxial growth process. In some examples, the in-situ doped well region includes an N-well or a P-well region. After formation of the in-situ doped layer on the fin, an undoped layer is formed on the in-situ doped layer, and a gate stack is formed over the undoped layer. The undoped layer may include an undoped channel region formed by an epitaxial growth process. In various examples, a source region and a drain region are formed adjacent to and on either side of the undoped channel region.

A method for fabricating semiconductor device is disclosed. The method includes the steps of: providing a substrate having at least a fin-shaped structure thereon and the fin-shaped structure includes a top portion and a bottom portion; forming a gate structure on the fin-shaped structure; forming a cap layer on the top portion of the fin-shaped structure not covered by the gate structure; performing an annealing process to drive germanium from the cap layer to the top portion of the fin-shaped structure; removing the cap layer; and forming an epitaxial layer around the top portion of the fin-shaped structure.

In a method of manufacturing a semiconductor device, a dummy gate structure is formed on a substrate. A first spacer layer is formed on the substrate to cover the dummy gate structure. A nitridation process is performed on the first spacer layer. An upper portion of the substrate adjacent to the dummy gate structure is removed to form a trench. An inner wall of the trench is cleaned. An epitaxial layer is formed to fill the trench. The dummy gate structure is replaced with a gate structure.

To satisfy both suppression of rise in contact resistance and improvement of breakdown voltage near the end part of a trench part. The trench part GT is provided between a source offset region and a drain offset region at least in plan view in a semiconductor layer, and is provided in a source-drain direction from the source offset region toward the drain offset region in plan view. A gate insulating film GI covers the side surface and the bottom surface of the trench part GT. A gate electrode is provided in the trench part at least in plan view, and contacts the gate insulating film GI. A contact GC contacts the gate electrode GE. The contact GC is disposed, shifted in a first direction perpendicular to the source-drain direction relative to the centerline in the trench part GT extending in the source-drain direction in plan view, and is provided in the trench part GT in plan view.

A back end of line device and method for fabricating a transistor device include a substrate having an insulating layer formed thereon and a channel layer formed on the insulating layer. A gate structure is formed on the channel layer. Dopants are implanted into an upper portion of the channel layer on opposite sides of the gate structure to form shallow source and drain regions using a low temperature implantation process. An epitaxial layer is selectively grown on the shallow source and drain regions to form raised regions above the channel layer and against the gate structure using a low temperature plasma enhanced chemical vapor deposition process, wherein low temperature is less than about 400 degrees Celsius.

A method for manufacturing a semiconductor device is disclosed. The method comprises: forming a T-shape dummy gate structure on the substrate; removing the T-shape dummy gate structure and retaining a T-shape gate trench; forming a T-shape metal gate structure by filling a metal layer in the T-shape gate trench. According to the semiconductor device manufacturing method disclosed in the present application, the overhang phenomenon and the formation of voids are avoided in the subsequent metal gate filling process by forming a T-shape dummy gate and a T-shape gate trench, and the device performance is improved.

A method for fabricating semiconductor device is disclosed. First, a substrate is provided, a gate structure is formed on the substrate, a spacer is formed around the gate structure, and an epitaxial layer is formed in the substrate adjacent to the spacer. Preferably, the step of forming the epitaxial layer further includes: forming a buffer layer in the substrate; forming a bulk layer on the buffer layer; forming a linear gradient cap on the bulk layer, and forming a silicon cap on the linear gradient cap. Preferably, the etching to deposition ratio of the linear gradient cap is greater than 50% and less than 100%.

A method of manufacturing a field effect transistor using a gate last process includes providing the field effect transistor which includes a high-k dielectric formed between an elevated source and an elevated drain and surrounding a metal gate, and performing a chemical mechanical planarization (CMP) process on an upper surface of the elevated source, and in which a height of the metal gate becomes lower than a height of the elevated source according to the CMP process.