A vapor phase epitaxy method of growing a III-V layer with a doping that changes from a first conductivity type to a second conductivity type on a surface of a substrate or a preceding layer in a reaction chamber from the vapor phase from an epitaxial gas flow comprising a carrier gas, at least one first precursor for an element from main group III, and at least one second precursor for an element from main group V, wherein when a first growth height is reached, a first initial doping level of the first conductivity type is set by means of a ratio of a first mass flow of the first precursor to a second mass flow of the second precursor, then the first initial doping level is reduced to a second initial doping level of the first or low second conductivity type.

A device includes a semiconductive fin, an isolation structure, a gate structure, dielectric spacers, and source/drain epitaxial structures. The isolation structure surrounds a bottom portion of the semiconductive fin. The gate structure is over the semiconductive fin. The dielectric spacers are on opposite sides of the semiconductive fin and over the isolation structure. The dielectric spacers include nitride. The source/drain epitaxial structures are on opposite sides of the gate structure and over the dielectric spacers. The source/drain epitaxial structures have hexagon shapes.

A semiconductor device is provided. The semiconductor device includes a substrate and a semiconductor layer formed over the substrate. The semiconductor device further includes a first channel layer and a second channel layer and a first insulating structure interposing the first channel layer and the semiconductor layer and a second insulating structure interposing the first channel layer and the second channel layer. The semiconductor device further includes a gate stack abutting the first channel layer and the second channel layer, and the gate stack includes a first portion vertically sandwiched between the first channel layer and the semiconductor layer and a second portion vertically sandwiched between the first channel layer and the second channel layer.

A field effect transistor (FET) device includes a substrate, a gate structure over the substrate, a channel region under the gate structure, the channel region including a first semiconductor material, and a second semiconductor material interposed between the first semiconductor material and the substrate. The second semiconductor material is different from the first semiconductor material. An interface of the second semiconductor material with the first semiconductor material has facets. A surface of the second semiconductor material interfacing with the substrate is non-planar.

Embodiments of methods to form three-dimensional (3D) memory devices include the following operations. First, an initial channel hole is formed in a stack structure of a plurality first layers and a plurality of second layers alternatingly arranged over a substrate. An offset is formed between a side surface of each one of the plurality of first layers and a side surface of each one of the plurality of second layers on a sidewall of the initial channel hole to form a channel hole. A semiconductor channel is formed by filling the channel hole with a channel-forming structure, the semiconductor channel having a memory layer including a plurality of first memory portions each surrounding a bottom of a respective second layer and a plurality of second memory portions each connecting adjacent first memory portions.

A method includes etching a hybrid substrate to form a recess extending into the hybrid substrate. The hybrid substrate includes a first semiconductor layer having a first surface orientation, a dielectric layer over the first semiconductor layer, and a second semiconductor layer having a second surface orientation different from the first surface orientation. After the etching, a top surface of the first semiconductor layer is exposed to the recess. A spacer is formed on a sidewall of the recess. The spacer contacts a sidewall of the dielectric layer and a sidewall of the second semiconductor layer. An epitaxy is performed to grow an epitaxy semiconductor region from the first semiconductor layer. The spacer is removed.

A method includes providing a semiconductor structure having an active region and an isolation structure adjacent to the active region, the active region having source and drain regions sandwiching a channel region for a transistor, the semiconductor structure further having a gate structure over the channel region. The method further includes etching a trench in one of the source and drain regions, wherein the trench exposes a portion of a sidewall of the isolation structure, epitaxially growing a first semiconductor layer in the trench, epitaxially growing a second semiconductor layer over the first semiconductor layer, changing a crystalline facet orientation of a portion of a top surface of the second semiconductor layer by an etching process, and epitaxially growing a third semiconductor layer over the second semiconductor layer after the changing of the crystalline facet orientation.

A semiconductor processing system includes a gas delivery module, and a chamber body connected to the gas delivery module. The divider has an aperture, is fixed within an interior of the chamber body, and separates an interior of the chamber body into upper and lower chambers, the aperture fluidly coupling the lower chamber to the upper chamber. A susceptor is arranged within the aperture. A controller is operably connected to the gas delivery module to purge the lower chamber with a first purge flow including an etchant while etching the upper chamber, purge the lower chamber with a second purge flow including the etchant while depositing a precoat in the upper chamber, and purge the lower chamber with a third purge flow including the etchant while depositing a film onto a substrate in the upper chamber. Film deposition methods and lower chamber etchant purge kits are also described.

A semiconductor device includes a stack structure, a channel layer passing through the stack structure, a memory layer enclosing the channel layer and including first and second openings which expose the channel layer, a well plate coupled to the channel layer through the first opening, and a source plate coupled to the channel layer through the second opening.

Embodiments of 3D memory devices having a pocket structure in memory strings and methods for forming the same are disclosed. In an example, a 3D memory device includes a substrate, a selective epitaxial layer on the substrate, a memory stack including interleaved conductive layers and dielectric layers on the selective epitaxial layer, and a memory string including a channel structure extending vertically in the memory stack and a pocket structure extending vertically in the selective epitaxial layer. The memory string includes a semiconductor channel extending vertically in the channel structure, and extending vertically and laterally in the pocket structure and in contact with the selective epitaxial layer.