One aspect of the disclosure is directed to a method of forming a semiconductor structure including: forming a fin over a substrate within a device region, the fin including alternating layers of a sacrificial material and a semiconductor material, and including a lower channel region; forming a dopant-containing layer over the fin and the substrate; exposing an upper portion of the fin by removing the dopant-containing layer from the upper portion of the fin; removing the sacrificial material from the fin thereby suspending the semiconductor material within the fin between a pair of spacers and over the lower channel region of the fin; performing an anneal to drive in dopants from the dopant-containing layer to the lower channel region of the fin; and forming an active gate over the lower channel region of the fin and substantially surrounding the suspended semiconductor material over the lower channel region of the fin.

A semiconductor device includes first and second dielectric fins disposed above a substrate, a semiconductor channel layer sandwiched between the first and second dielectric fins, a gate structure engaging the semiconductor channel layer, a source/drain (S/D) feature abutting the semiconductor channel layer and sandwiched between the first and second dielectric fins, and an air gap sandwiched between the first and second dielectric fins. The air gap exposes a first sidewall of the S/D feature facing the first dielectric fin and a second sidewall of the S/D feature facing the second dielectric fin.

A semiconductor device includes first and second nanowire structures, first and second annular hafnium oxide layers, first and second annular cap layers, and first and second metal gate electrodes. The first and second nanowire structures are suspended over a substrate and respectively have an n-channel region and a p-channel region. The first and second annular hafnium oxide layers encircle the n-channel region and the p-channel region, respectively. The first and second annular cap layers encircle the first and second annular hafnium oxide layers, respectively. The first and second annular cap layers are made of a same material that is lanthanum oxide, yttrium oxide, or strontium oxide. The first and second metal gate electrodes encircle the first and second annular cap layers, respectively. The first and second metal gate electrodes have a same metal composition.

An integrated circuit die has a layer of first semiconductor material comprising a Group III element and nitrogen and having a first bandgap. A first transistor structure on a first region of the die has: a quantum well (QW) structure that includes at least a portion of the first semiconductor material and a second semiconductor material having a second bandgap smaller than the first bandgap, a first source and a first drain in contact with the QW structure, and a gate structure in contact with the QW structure between the first source and the first drain. A second transistor structure on a second region of the die has a second source and a second drain in contact with a semiconductor body, and a second gate structure in contact with the semiconductor body between the second source and the second drain. The semiconductor body comprises a Group III element and nitrogen.

The disclosure relates to a semiconductor device. An exemplary structure for a semiconductor device comprises a nanowire structure comprising a channel region between a source region and a drain region; and a metal gate surrounding a portion the channel region, wherein the metal gate comprising a first gate portion adjacent to the source region having a first thickness and a second gate portion adjacent to the drain region having a second thickness less than the first thickness.

This disclosure provides a horizontal structure by using a double STI recess method. The double STI recess method includes: forming a plurality of fins on the substrate; forming shallow trench isolation between the fins; performing first etch-back on the shallow trench isolation; forming source and drain regions adjacent to channels of the fins; and performing second etch-back on the shallow trench isolations to expose a lower portion of the fins as a larger process window for forming gates of the fins.

Transistor devices having a doped buffer or sub-structure between an active channel and a substrate. In one embodiment, a p-type dopant, such as magnesium, zinc, carbon, beryllium, and the like, may be introduced in the formation of the sub-structure, wherein the dopant may act as a p/n junction at the active channel to source and drain interfaces and decrease the off-state leakage path. In another embodiment, the material used for the formation of the doped sub-structure may be substantially the same as the material, without the dopant, used for the formation of the active channel, such that no heterojunction will be formed which could result in crystalline imperfections.

A method for fabricating a transistor is provided. The method includes providing a semiconductor substrate; and forming at least a nanowire suspending in the semiconductor substrate. The method also includes forming a channel layer surrounding the nanowire; and forming a contact layer surrounding the channel layer. Further, the method includes forming a trench exposing the channel layer and surrounding the channel layer in the contact layer; and forming a potential barrier layer on the bottom of the trench and surrounding the channel layer. Further, the method also includes forming a gate structure surrounding the potential barrier layer and covering portions of the contact layer; and forming a source and a drain region on the contact layer at two sides of the gate structure, respectively.

Multiple non-silicon semiconductor material layers may be stacked within a fin structure. The multiple non-silicon semiconductor material layers may include one or more layers that are suitable for P-type transistors. The multiple non-silicon semiconductor material layers may further include one or more one or more layers that are suited for N-type transistors. The multiple non-silicon semiconductor material layers may further include one or more intervening layers separating the N-type from the P-type layers. The intervening layers may be at least partially sacrificial, for example to allow one or more of a gate, source, or drain to wrap completely around a channel region of one or more of the N-type and P-type transistors.

Integrated circuit structures including a buried etch-stop layer to help control transistor source/drain depth are provided herein. The buried etch-stop layer addresses the issue of the source/drain etch (or epi-undercut (EUC) etch) going below the bottom of the active height of the channel region, as such an issue can result in un-controlled sub-fin leakage that causes power consumption degradation and other undesired performance issues. The buried etch-stop layer is formed below the channel material, such as in the epitaxial stack that includes the channel material, and acts to slow the removal of material after the channel material has been removed when etching to form the source/drain trenches. In other words, the buried etch-stop layer includes different material from the channel material that can be etched, for at least one given etchant, at a relatively slower rate than the channel material to help control the source/drain trench depth.