A p-type field effect transistor includes a pair of spacers over a substrate top surface. The p-type field effect transistor includes a channel recess cavity in the substrate top surface between the pair of spacers. The p-type field effect transistor includes a gate stack with a bottom portion in the channel recess cavity. The p-type field effect transistor includes a source/drain (S/D) recess cavity including a bottom surface and sidewalls below the substrate top surface, wherein the S/D recess cavity includes a portion extending below the gate stack. The p-type field effect transistor includes a strained material filling the S/D recess cavity. The p-type field effect transistor further includes a source/drain (S/D) extension substantially conformably surrounding the bottom surface and sidewalls of the S/D recess cavity. The S/D extension includes a portion between the gate stack and the S/D recess cavity.

A method for filling gaps between structures includes forming a plurality of high aspect ratio structures adjacent to one another with gaps, forming a first dielectric layer on tops of the structures and conformally depositing a spacer dielectric layer over the structures. The spacer dielectric layer is removed from horizontal surfaces and a protection layer is conformally deposited over the structures. The gaps are filled with a flowable dielectric, which is recessed to a height along sidewalls of the structures by a selective etch process such that the protection layer protects the spacer dielectric layer on sidewalls of the structures. The first dielectric layer and the spacer dielectric layer are exposed above the height using a higher etch resistance than the protection layer to maintain dimensions of the spacer layer dielectric through the etching processes. The gaps are filled by a high density plasma fill.

A method for filling gaps between structures includes forming a plurality of high aspect ratio structures adjacent to one another with gaps, forming a first dielectric layer on tops of the structures and conformally depositing a spacer dielectric layer over the structures. The spacer dielectric layer is removed from horizontal surfaces and a protection layer is conformally deposited over the structures. The gaps are filled with a flowable dielectric, which is recessed to a height along sidewalls of the structures by a selective etch process such that the protection layer protects the spacer dielectric layer on sidewalls of the structures. The first dielectric layer and the spacer dielectric layer are exposed above the height using a higher etch resistance than the protection layer to maintain dimensions of the spacer layer dielectric through the etching processes. The gaps are filled by a high density plasma fill.

A structure includes a substrate and a tunnel field effect transistor (TFET). The TFET includes a source region disposed in the substrate having an overlying source contact, the source region containing first semiconductor material having a first doping type; a drain region disposed in the substrate having an overlying drain contact, the drain region containing second semiconductor material having a second, opposite doping type; and a gate structure that overlies a channel region between the source and the drain. The source region and the drain region are asymmetric with respect to one another such that one contains a larger volume of semiconductor material than the other one. A method is disclosed to fabricate a plurality of the TFETs using a plurality of spaced apart mandrels having spacers. A pair of the mandrels and the associated spacers is processed to form four adjacent TFETs without requiring intervening lithographic processes.

Self-aligned contacts are provided. In an embodiment the self-aligned contacts are formed by partially removing a first dielectric material from adjacent to a gate electrode and fully removing a second dielectric material from adjacent to the gate electrode. A conductive material is deposited into the regions of the removed first dielectric material and the second dielectric material, and the conductive material and metal gates are recessed below a spacer. A dielectric layer is deposited over the recessed conductive material and the recessed metal gates, and the self-aligned contacts are formed through the dielectric layer.

Source/drain contact structures that exhibit low contact resistance and improved electromigration properties are provided. After forming a first contact conductor portion comprising a metal having a high resistance to electromigration such as tungsten at a bottom portion of source/drain contact trench to form direct contact with a source/drain region of a field effect transistor, a second contact conductor portion comprising a highly conductive metal such as copper or a copper alloy is formed over the first contact conductor portion.

In some examples, a transistor includes a drain, a channel, and a gate. The channel surrounds the drain and has a channel length to width ratio. The gate is over the channel to provide an active channel region that has an active channel region length to width ratio that is greater than the channel length to width ratio.

A device includes a semiconductor layer of a first conductivity type, and a first and a second body region over the semiconductor layer, wherein the first and the second body regions are of a second conductivity type opposite the first conductivity type. A doped semiconductor region of the first conductivity type is disposed between and contacting the first and the second body regions. A gate dielectric layer is disposed over the first and the second body regions and the doped semiconductor region. A first and a second gate electrode are disposed over the gate dielectric layer, and overlapping the first and the second body regions, respectively. The first and the second gate electrodes are physically separated from each other by a region, and are electrically interconnected. The region between the first and the second gate electrodes overlaps the doped semiconductor region.

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.

An integrated circuit structure includes a gate stack over a semiconductor substrate, and an opening extending into the semiconductor substrate, wherein the opening is adjacent to the gate stack. A first silicon germanium region is disposed in the opening, wherein the first silicon germanium region has a first germanium percentage. A second silicon germanium region is over the first silicon germanium region. The second silicon germanium region comprises a portion in the opening. The second silicon germanium region has a second germanium percentage greater than the first germanium percentage. A silicon cap substantially free from germanium is over the second silicon germanium region.