A method for forming strained fins includes etching trenches in a bulk substrate to form fins, filling the trenches with a dielectric fill and recessing the dielectric fill into the trenches to form shallow trench isolation regions. The fins are etched above the shallow trench isolation regions to form a staircase fin structure with narrow top portions of the fins. Gate structures are formed over the top portions of the fins. Raised source ad drain regions are epitaxially grown on opposite sides of the gate structure. A pre-morphization implant is performed to generate defects in the substrate to couple strain into the top portions of the fins.

The disclosed technology generally relates to semiconductor devices, and more particularly to transistor devices comprising multiple channels. In one aspect, a method of fabricating a transistor device comprises forming on the substrate a plurality of vertically repeating layer stacks each comprising a first layer, a second layer and a third layer stacked in a predetermined order, wherein each of the first, second and third layers is formed of silicon, silicon germanium or germanium and has a different germanium concentration compared to the other two of the first, second and third layers. The method additionally includes selectively removing the first layer with respect to the second and third layers from each of the layer stacks, such that a gap interposed between the second layer and the third layer is formed in each of the layer stacks. The method further includes selectively removing the second layer from each of the layer stacks with respect to the third layer, wherein removing the second layer comprises at least partially removing the second layer through the gap, thereby defining the channels comprising a plurality of vertically arranged third layers.

After semiconductor material portions and gate structures are formed on a substrate, a dielectric material layer is deposited on the semiconductor material portions and the gate structures. An anisotropic etch is performed on the dielectric material layer to form gate spacers, while a mask layer protects peripheral portions of the semiconductor material portions and the gate structures to avoid unwanted physical exposure of semiconductor surfaces. A selective epitaxy can be performed to form raised active regions on the semiconductor material portions. Formation of semiconductor growth defects during the selective epitaxy is prevented by the dielectric material layer. Alternately, a selective semiconductor deposition process can be performed after formation of dielectric gate spacers on gate structures overlying semiconductor material portions. Semiconductor growth defects can be removed by an etch while a mask layer protects raised active regions on the semiconductor material portions.

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 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 method for manufacturing a semiconductor device includes forming one or more fins extending in a first direction over a substrate. The one or more fins include a first region along the first direction and second regions on both sides of the first region along the first direction. A dopant is implanted in the first region of the fins but not in the second regions. A gate structure overlies the first region of the fins and source/drains are formed on the second regions of the fins.

First and second transistors with different electrical characteristics are supported by a substrate having a first-type dopant. The first transistor includes a well region within the substrate having the first-type dopant, a first body region within the well region having a second-type dopant and a first source region within the first body region and laterally offset from the well region by a first channel. The second transistor includes a second body region within the semiconductor substrate layer having the second-type dopant and a second source region within the second body region and laterally offset from material of the substrate by a second channel having a length greater than the length of the first channel. A gate region extends over portions of the first and second body regions for the first and second channels, respectively.

A method for integrating a vertical transistor and a three-dimensional channel transistor includes forming narrow fins and wide fins in a substrate; forming a first source/drain (S/D) region at a base of the narrow fin and forming a gate dielectric layer and a gate conductor layer over the narrow fin and the wide fin. The gate conductor layer and the gate dielectric layer are patterned to form a vertical gate structure and a three-dimensional (3D) gate structure. Gate spacers are formed over sidewalls of the gate structures. A planarizing layer is deposited over the vertical gate structure and the 3D gate structure. A top portion of the narrow fin is exposed. S/D regions are formed on opposite sides of the 3D gate structure to form a 3D transistor, and a second S/D region is formed on the top portion of the narrow fin to form a vertical transistor.

An integrated circuit is formed by providing a heavily doped substrate of a first conductivity type, forming a lightly doped lower epitaxial layer of the first conductivity type over the substrate, implanting dopants of the first conductivity type into the lower epitaxial layer in an area for a shallow component and blocking the dopants from an area for a deep component, forming a lightly doped upper epitaxial layer over the lower epitaxial layer and activating the implanted dopants to form a heavily doped region. The shallow component is formed over the heavily doped region, and the deep component is formed outside the heavily doped region, extending through the upper epitaxial layer into the lower epitaxial layer.

A semiconductor device includes at least a substrate, fin-shaped structures, a protection layer, epitaxial layers, and a gate electrode. The fin-shaped structures are disposed in a first region and a second region of the substrate. The protection layer conformally covers the surface of the substrate and the sidewalls of fin-shaped structures. The epitaxial layers respectively conformally and directly cover the fin-shaped structures in the first region. The gate electrode covers the fin-shaped structures in the second region, and the protection layer is disposed between the gate electrode and the fin-shaped structures.

A semiconductor structure includes a semiconductor substrate; a planar transistor on a first portion of the semiconductor substrate, wherein the first portion of the semiconductor substrate has a first top surface; and a multiple-gate transistor on a second portion of the semiconductor substrate. The second portion of the semiconductor substrate is recessed from the first top surface to form a fin of the multiple-gate transistor. The fin is electrically isolated from the semiconductor substrate by an insulator.