Semiconductor devices including a stressor in a recess and methods of forming the semiconductor devices are provided. The methods may include forming a trench in an active region and the trench may include a notched portion of the active region. The methods may also include forming an embedded stressor in the trench. The embedded stressor may include a lower semiconductor layer and an upper semiconductor layer, which has a width narrower than a width of the lower semiconductor layer. A side of the upper semiconductor layer may not be aligned with a side of the lower semiconductor layer and an uppermost surface of the upper semiconductor layer may be higher than an uppermost surface of the active region.

Microelectronic structures embodying the present invention include a field effect transistor (FET) having highly conductive source/drain extensions. Formation of such highly conductive source/drain extensions includes forming a passivated recess which is back filled by epitaxial deposition of doped material to form the source/drain junctions. The recesses include a laterally extending region that underlies a portion of the gate structure. Such a lateral extension may underlie a sidewall spacer adjacent to the vertical sidewalls of the gate electrode, or may extend further into the channel portion of a FET such that the lateral recess underlies the gate electrode portion of the gate structure. In one embodiment the recess is back filled by an in-situ epitaxial deposition of a bilayer of oppositely doped material. In this way, a very abrupt junction is achieved that provides a relatively low resistance source/drain extension and further provides good off-state subthreshold leakage characteristics. Alternative embodiments can be implemented with a back filled recess of a single conductivity type.

A semiconductor device includes a substrate, at least one source drain feature, a gate structure, and at least one gate spacer. The source/drain feature is present at least partially in the substrate. The gate structure is present on the substrate. The gate spacer is present on at least one sidewall of the gate structure. At least a bottom portion of the gate spacer has a plurality of dopants therein.

A method for fabricating a semiconductor device may include: preparing a semiconductor substrate including a doping region; performing tilt implantation using a first additional dopant to form an amorphous region in the doping region; doping a second additional dopant in the amorphous region; forming a metal layer on the doped amorphous region; and reacting the doped amorphous region with the metal layer to form metal silicide

The present invention provides a low temperature polysilicon thin film transistor and a fabricating method thereof. According to the method, a laser annealing process is performed to a remained portion of a a-Si layer on a substrate to form a first lightly doped drain (LDD) terminal, a second LDD terminal, a first phosphor material structure and a second phosphor material structure. A gate metal layer is then formed on the remained portion of the a-Si layer. A source metal layer and a drain metal layer are formed on the first doped layer and the second doped layer located at opposite sides of the gate metal layer, respectively. The present invention use the high temperature of the laser annealing process to perform a heat diffusion of phosphor material to form the LDD terminal and the phosphor material structure, the times of photomasks are used is reduced, and the process is simplified.

A source-drain structure and method of manufacturing the same are disclosed. The source-drain structure includes a substrate containing a drain region and a source region. The drain region includes a lightly-doped ultra-shallow junction and a heavily-doped region, and a drain-substrate junction disposed in the vicinity of a junction between a side portion and a bottom portion of the lightly-doped ultra-shallow junction and the substrate, a plurality of impurity ions in the drain-substrate junction and a plurality of impurity ions in the lightly-doped ultra-shallow junction are opposite-conductivity type ions. The drain-substrate junction can smooth out the steep surface of the lightly-doped ultra-shallow junction to minimize the maximum electric field and reduce the ion flow close to the channel, and effectively reduce the inter-band tunneling hot electron effect.

A gate structure includes at least one spacer defining a gate region over a semiconductor substrate, a gate dielectric layer disposed on the gate region over the semiconductor substrate, a first work function metal layer disposed over the gate dielectric layer and lining a bottom surface of an inner sidewall of the spacer, and a filling metal partially wrapped by the first work function metal layer. The filling metal includes a first portion and a second portion, wherein the first portion is between the second portion and the semiconductor substrate, and the second portion is wider than the first portion.

A semiconductor-on-insulator (SOI) device includes a semiconductor layer situated over a buried oxide layer, the buried oxide layer being situated over a substrate. An SOI transistor is situated in the semiconductor layer and includes a transistor body, gate fingers, source regions, and drain regions. The transistor body has a first conductivity type. The source regions and the drain regions have a second conductivity type opposite to the first conductivity type. The transistor body is electrically tied to at least one source region. An asymmetric halo-implant region having the first conductivity type adjoins the at least one source region. No halo-implant region adjoins the drain regions.

A semiconductor device and a manufacturing method therefor. The semiconductor device comprises: a semiconductor substrate. A first drift region is formed in the semiconductor substrate. A gate structure is formed on the semiconductor substrate A part of the gate structure covers a part of the first drift region. A first trench is formed in the first drift region, and a drain region is formed in the semiconductor substrate at the bottom of the first trench.

Present disclosure provides a transistor structure, including a substrate, a first gate extending along a longitudinal direction over the substrate, the first gate including a gate electrode, a second gate over the substrate and apart from the first gate, a source region of a first conductivity type in the substrate, aligning to an edge in proximity to a side of the first gate, a P-type well surrounding the source region, a drain region of the first conductivity type in the substrate, an N-type well surrounding the drain region, the second gate is entirely within a vertical projection area of the N-type well and a bottom surface of the P-type well and a bottom surface of the N-type well are substantially at a same depth from the first gate.