In some embodiments, a compound semiconductor is formed by diffusion of semiconductor species from a source semiconductor layer into semiconductor material in a substrate. The source semiconductor layer may be an amorphous or polycrystalline structure, and provides a source of semiconductor species for later diffusion into the other semiconductor material. Advantageously, such a semiconductor layer may be more conformal than an epitaxially grown, crystalline semiconductor layer. As a result, this more conformal semiconductor layer acts as a uniform source of the semiconductor species for diffusion into the semiconductor material in the substrate. In some embodiments, an interlayer is formed between the source semiconductor layer and the substrate, and then the interlayer is trimmed before depositing the source semiconductor layer. In some other embodiments, the source semiconductor layer is deposited directly on the substrate, and has an amorphous or polycrystalline structure.

A semiconductor device includes a semiconductor substrate having a first region and a second region, a plurality of first semiconductor fins in the first region, a plurality of second semiconductor fins in the second region, a first solid-state dopant source layer within the first region on the semiconductor substrate, a first insulating buffer layer on the first solid-state dopant source layer, a second solid-state dopant source layer within the second region on the semiconductor substrate, a second insulating buffer layer on the second solid-state dopant source layer and on the first insulating buffer layer, a first fin bump in the first region, and a second fin bump in the second region. The first fin bump includes a first sidewall spacer and the second fin bump comprises a second sidewall spacer. The first sidewall spacer has a structure that is different from that of the second sidewall spacer.

A thin film containing a dopant is deposited on a surface of a semiconductor wafer. The semiconductor wafer on which the thin film containing the dopant is deposited is rapidly heated to a first peak temperature by irradiation with light from halogen lamps, so that the dopant is diffused from the thin film into the surface of the semiconductor wafer. The thermal diffusion using the rapid heating achieves the introduction of the necessary and sufficient dopant into the semiconductor wafer without producing defects. The surface of the semiconductor wafer is heated to a second peak temperature by further irradiating the semiconductor wafer with flashes of light from flash lamps, so that the dopant is activated. The flash irradiation which is extremely short in irradiation time achieves a high activation rate without excessive diffusion of the dopant.

A fin field effect transistor includes a Si fin including a central portion between end portions of the fin, and a SiGe channel region disposed on the central portion of the fin. The SiGe channel region includes a facet free SiGe region having Ge atoms diffused into the Si fin and includes a same shape as the Si fin outside the central portion.

A three-dimensional stacked memory device provides uniform programming speeds for a block of memory cells. The channel layers of the memory strings which are relatively close to a local interconnect of a stack are doped to account for a reduced blocking oxide thickness. Channel layers of remaining memory strings are undoped. The doping can be performing by masking the channel layers which are to remain undoped while exposing the other memory holes to a dopant. The dopant can be provided, e.g., in a carrier gas, spin on glass or other solid, or by plasma doping. An n-type dopant such as antimony, arsenic or phosphorus may be used. Heating causes the dopants to diffuse into the channel layer. Another approach deposits doped silicon for some of the channel layers and undoped silicon for other channel layers.

One illustrative method disclosed includes, among other things, forming a gate structure around a fin and above a layer of insulating material, forming a gate spacer adjacent the gate structure and a fin spacer positioned adjacent the fin above the insulating material, the fin spacer leaving an upper surface of the fin exposed, and performing at least one etching process to remove at least a portion of the fin positioned between the fin spacer, the fin having a recessed upper surface that at least partially defines a fin recess positioned between the fin spacer. In this example, the method further includes forming an epi semiconductor material on the fin recess and removing the fin spacer from adjacent the epi semiconductor material while leaving a portion of the gate spacer in position adjacent the gate structure.

An impurity source film is formed along a portion of a non-planar semiconductor fin structure. The impurity source film may serve as source of an impurity that becomes electrically active subsequent to diffusing from the source film into the semiconductor fin. In one embodiment, an impurity source film is disposed adjacent to a sidewall surface of a portion of a sub-fin region disposed between an active region of the fin and the substrate and is more proximate to the substrate than to the active area. In further embodiments, the impurity source film may provide a source of dopant that renders the sub-fin region complementarily doped relative to a region of the substrate forming a P/N junction that is at least part of an isolation structure electrically isolating the active fin region from a region of the substrate.

A semiconductor device includes: a fin-shaped structure on a substrate, in which the fin-shaped structure includes a top portion and a bottom portion; a doped layer around the bottom portion of the fin-shaped structure; a first liner on the doped layer, and a second liner on the top portion and the bottom portion of the fin-shaped structure. Preferably, the first liner and the second liner are made of different material.

A method for channel formation in a fin transistor includes removing a dummy gate and dielectric from a dummy gate structure to expose a region of an underlying fin and depositing an amorphous layer including Ge over the region of the underlying fin. The amorphous layer is oxidized to condense out Ge and diffuse the Ge into the region of the underlying fin to form a channel region with Ge in the fin.

Device structures for a FinFET and fabrication methods for making a device structure for a FinFET. A first layer containing a first dopant is formed on a first region of a substrate. A second layer containing a second dopant is formed on a second region of the substrate. A first plurality of fins are formed and are each located in a respective trench extending from the substrate through the first layer. A second plurality of fins are formed and are each located in a respective trench extending from the substrate through the second layer. The first dopant is transferred from the first layer to a first section in each of the first plurality of fins and the second dopant is transferred from the second layer to a first section in each of the second plurality of fins.