Semiconductor devices having necked semiconductor bodies and methods of forming semiconductor bodies of varying width are described. For example, a semiconductor device includes a semiconductor body disposed above a substrate. A gate electrode stack is disposed over a portion of the semiconductor body to define a channel region in the semiconductor body under the gate electrode stack. Source and drain regions are defined in the semiconductor body on either side of the gate electrode stack. Sidewall spacers are disposed adjacent to the gate electrode stack and over only a portion of the source and drain regions. The portion of the source and drain regions under the sidewall spacers has a height and a width greater than a height and a width of the channel region of the semiconductor body.

A semiconductor structure and a forming method thereof are provided. One form of a semiconductor structure includes: a first device structure, including a first substrate and a first device formed on the first substrate, the first device including a first channel layer structure located on the first substrate, a first device gate structure extending across the first channel layer structure, and a first source-drain doping region located in the first channel layer structure on two sides of the first device gate structure; and a second device structure, located on a front surface of the first device structure, including a second substrate located on the first device structure and a second device formed on the second substrate, the second device including a second channel layer structure located on the second substrate, a second device gate structure extending across the second channel layer structure, and a second source-drain doping region located in the second channel layer structure on two sides of the second device gate structure, where projections of the second channel layer structure and the first channel layer structure onto the first substrate intersect non-orthogonally. The electricity of the first device can be led out according to the present disclosure.

An integrated circuit may include oscillator circuitry having a resonator formed from fin field-effect transistor (FinFET) devices. The resonator may include drive cells of alternating polarities and sense cells interposed between the drive cells. The resonator may be connected in a feedback loop within the oscillator circuitry. The oscillator circuitry may include an amplifier having an input coupled to the sense cells and an output coupled to the drive cells. The oscillator circuitry may also include a separate inductor and capacitor based oscillator, where the resonator serves as a separate output filter stage for the inductor and capacitor based oscillator.

A semiconductor radiation monitor (i.e., dosimeter) is provided that has an oxide charge storage region located on a first side of a semiconductor fin and a functional gate structure located on a second side of the semiconductor fin that is opposite the first side. Charges are created in the oxide charge storage region that is located on the first side of the semiconductor fin and detected on the second side of the semiconductor fin by the functional gate structure. Multiple semiconductor fins in parallel can form a dense and very sensitive semiconductor radiation monitor.

A source/drain region of a semiconductor device is formed using an epitaxial growth process. In an embodiment a first step comprises forming a bulk region of the source/drain region using a first precursor, a second precursor, and an etching precursor. A second step comprises cleaning the bulk region with the etchant along with introducing a shaping dopant to the bulk region in order to modify the crystalline structure of the exposed surfaces. A third step comprises forming a finishing region of the source/drain region using the first precursor, the second precursor, and the etching precursor.

A 3D semiconductor device, the device including: a first level, where the first level includes a first layer, the first layer including first transistors, and where the first level includes a second layer, the second layer including first interconnections; a second level overlaying the first level, where the second level includes a third layer, the third layer including second transistors, and where the second level includes a fourth layer, the fourth layer including second interconnections; and a plurality of connection paths, where the plurality of connection paths provides connections from a plurality of the first transistors to a plurality of the second transistors, where the second level is bonded to the first level, where the bonded includes oxide to oxide bond regions, where the bonded includes metal to metal bond regions, where the third layer includes crystalline silicon, and where the second level includes at least one phase-lock-loop (“PLL”) circuit.

A 3D semiconductor device including: a first level, where the first level includes a first layer and first transistors, and where the first level includes a second layer including first interconnections; a second level overlaying the first level, where the second level includes a third layer, the third layer including second transistors, and where the second level includes a fourth layer, the fourth layer including second interconnections; a plurality of connection paths, where the plurality of connection paths provides connections from a plurality of the first transistors to a plurality of the second transistors, where the second level is bonded to the first level, where the bonded includes oxide to oxide bond regions, where the bonded includes metal to metal bond regions, where the second level includes at least one memory array, where the third layer includes crystalline silicon; and where the second level includes at least one SerDes circuit.

A 3D semiconductor device including: a first level, where the first level includes a first layer and first transistors, and where the first level includes a second layer including first interconnections; a second level overlaying the first level, where the second level includes a third layer, the third layer including second transistors, and where the second level includes a fourth layer, the fourth layer including second interconnections; a plurality of connection paths, where the plurality of connection paths provides connections from a plurality of the first transistors to a plurality of the second transistors, where the second level is bonded to the first level, where the bonded includes oxide to oxide bond regions, where the bonded includes metal to metal bond regions, where the second level includes at least one memory array, where the third layer includes crystalline silicon; and where the second level includes at least one SerDes circuit.

A 3D semiconductor device, the device including: a first level, where the first level includes a first layer, the first layer including first transistors, and where the first level includes a second layer, the second layer including first interconnections; a second level overlaying the first level, where the second level includes a third layer, the third layer including second transistors, and where the second level includes a fourth layer, the fourth layer including second interconnections; and a plurality of connection paths, where the plurality of connection paths provides connections from a plurality of the first transistors to a plurality of the second transistors, where the second level is bonded to the first level, where the bonded includes oxide to oxide bond regions, where the bonded includes metal to metal bond regions, where the third layer includes crystalline silicon, and where the second level includes at least one phase-lock-loop (“PLL”) circuit.

A method includes forming a fin structure over a semiconductor substrate; forming a liner covering the fin structure; etching back the liner to expose an upper portion of the fin structure; forming a spacer covering the upper portion of the fin structure; etching the liner to expose a middle portion of the fin structure, wherein the remaining liner covers a lower portion of the fin structure; etching the middle portion of the fin structure; and forming a first source/drain structure surrounding the middle portion of the fin structure.