Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a source structure in a semiconductor substrate. The semiconductor device structure also includes a channel layer over the semiconductor substrate. A first portion of the channel layer covers a portion of the source structure. A second portion of the channel layer laterally extends away from the source structure. The semiconductor device structure further includes a drain structure over the semiconductor substrate. The drain structure and the source structure have different conductivity types. The drain structure adjoins the second portion of the channel layer.

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.

An integrated circuit device includes a substrate including a first region and a second region, a first transistor in the first region, the first transistor being an N-type transistor and including a first silicon-germanium layer on the substrate, and a first gate electrode on the first silicon-germanium layer, and a second transistor in the second region and including a second gate electrode, the second transistor not having a silicon-germanium layer between the substrate and the second gate electrode.

A method of fabricating a MOSFET with an undoped channel is disclosed. The method comprises fabricating on a substrate a semiconductor structure having a dummy poly gate, dummy interlayer (IL) oxide, and a doped channel. The method further comprises removing the dummy poly gate and the dummy IL oxide to expose the doped channel, removing the doped channel from an area on the substrate, forming an undoped channel for the semiconductor structure at the area on the substrate, and forming a metal gate for the semiconductor structure. Removing the dummy poly gate may comprise dry and wet etch operations. Removing the dummy IL oxide may comprise dry etch operations. Removing the doped channel may comprise anisotropic etch operations on the substrate. Forming an undoped channel may comprise applying an epitaxial process to grow the undoped channel. The method may further comprise growing IL oxide above the undoped channel.

Some embodiments of the present disclosure relate to a transistor device formed in a semiconductor substrate containing dopant impurities of a first impurity type. The transistor device includes channel composed of a delta-doped layer comprising dopant impurities of the first impurity type, and configured to produce a peak dopant concentration within the channel. The channel further includes a layer of carbon-containing material overlying the delta-doped layer, and configured to prevent back diffusion of dopants from the delta-doped layer and semiconductor substrate. The channel also includes of a layer of substrate material overlying the layer of carbon-containing material, and configured to achieve steep retrograde dopant concentration profile a near a surface of the channel. In some embodiments, a counter-doped layer underlies the delta-doped layer configured to reduce leakage within the semiconductor substrate, and includes dopant impurities of a second impurity type, which is opposite the first impurity type.

A method for making an integrated circuit includes a) providing a substrate including n-type metal oxide semiconductor field effect transistors (NMOSFETs) and p-type metal oxide semiconductor field effect transistors (PMOSFETs), wherein channel regions of the NMOSFETs and the PMOSFETs include germanium; b) depositing and patterning a mask layer to mask the channel regions of the PMOSFETs and to not mask the channel regions of the NMOSFETs; c) passivating an exposed surface of the substrate; d) removing the mask layer; and e) depositing a metal contact layer on both the NMOSFETs and the PMOSFETs.

A method for forming field effect transistors (FETs) in a multiple wafers per batch epi-reactor includes, providing substrates having therein at least one semiconductor (SC) region with a substantially flat outer surface, modifying such substantially flat outer surface to form a convex-outward curved surface, forming an epitaxial semiconductor layer on the curved surface, and incorporating the epitaxial layer in a field effect transistor formed on the substrate. Where the SC region is of silicon, the epitaxial layer can include silicon-germanium. In a preferred embodiment, the epi-layer forms part of the FET channel. Because of the convex-outward curved surface, the epi-layer grown thereon has much more uniform thickness even when formed in a high volume reactor holding as many as 100 or more substrates per batch. FETs with much more uniform properties are obtained, thereby greatly increasing the manufacturing yield and reducing the cost.

An integrated circuit die includes a substrate having a first layer of semiconductor material, a layer of dielectric material on the first layer of semiconductor material, and a second layer of semiconductor material on the layer of dielectric material. An extended channel region of a transistor is positioned in the second layer of semiconductor material, interacting with a top surface, side surfaces, and potentially portions of a bottom surface of the second layer of semiconductor material. A gate dielectric is positioned on a top surface and on the exposed side surface of the second layer of semiconductor material. A gate electrode is positioned on the top surface and the exposed side surface of the second layer of semiconductor material.

The present disclosure relates to a transistor device having a channel region comprising a sandwich film stack with a plurality of different layers that improve device performance, and an associated apparatus. In some embodiments, the transistor device has a source region and a drain region disposed within a semiconductor substrate. A sandwich film stack is laterally positioned between the source region and the drain region. The sandwich film stack has a lower layer, a middle layer of a carbon doped semiconductor material disposed over the lower layer, and an upper layer disposed over the middle layer. A gate structure is disposed over the sandwich film stack. The gate structure is configured to control a flow of charge carriers in a channel region located between the source region and the drain region.

Some embodiments of the present disclosure relate to a semiconductor device configured to mitigate against parasitic coupling while maintaining threshold voltage control for comparatively narrow transistors. In some embodiments, a semiconductor device formed on a semiconductor substrate. The semiconductor device comprises a channel comprising an epitaxial layer that forms an outgrowth above the surface of the semiconductor substrate, and a gate material formed over the epitaxial layer. In some embodiments, a method of forming a semiconductor device is disclosed. The method comprises etching the surface of a semiconductor substrate to form a recess between first and second isolation structures, forming an epitaxial layer within the recess that forms an outgrowth above the surface of the semiconductor substrate, and forming a gate material over the epitaxial layer. Other embodiments are also disclosed.