An alternating stack of layers of a first epitaxial semiconductor material and a second epitaxial semiconductor material is formed on a substrate. A fin stack is formed by patterning the alternating stack into a shape of a fin having a parallel pair of vertical sidewalls. After formation of a disposable gate structure and an optional gate spacer, raised active regions can be formed on end portions of the fin stack. A planarization dielectric layer is formed, and the disposable gate structure is subsequently removed to form a gate cavity. A crystallographic etch is performed on the first epitaxial semiconductor material to form vertically separated pairs of an upright triangular semiconductor nanowire and an inverted triangular semiconductor nanowire. Portions of the epitaxial disposable material are subsequently removed. After an optional anneal, the gate cavity is filled with a gate dielectric and a gate electrode to form a field effect transistor.

One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as nanowires, include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).

A semiconductor device includes a drain, a source, a gate electrode, and a nanowire between the source and drain. The nanowire has a first section with a first thickness and a second section with a second thickness greater than the first thickness. The second section is between the first section and at least one of the source or drain. The first nanowire includes a channel when a voltage is applied to the gate electrode.

Devices and methods for forming a device are presented. The method includes providing a substrate prepared with at least a first region for accommodating an anti-fuse based memory cell. A fin structure is formed in the first region. The fin structure includes top and bottom fin portions and includes channel and non-channel regions defined along the length of the fin structure. An isolation layer is formed on the substrate. The isolation layer has a top isolation surface disposed below a top fin surface, leaving the top fin portion exposed. At least a portion of the exposed top fin portion in the channel region is processed to form a sharpened tip profile at top of the fin. A gate having a gate dielectric and a metal gate electrode is formed over the substrate. The gate wraps around the channel region of the fin structure.

Devices and methods for forming a device are presented. The method includes providing a substrate prepared with at least a first region for accommodating an anti-fuse based memory cell. A fin structure is formed in the first region. The fin structure includes top and bottom fin portions and includes channel and non-channel regions defined along the length of the fin structure. An isolation layer is formed on the substrate. The isolation layer has a top isolation surface disposed below a top fin surface, leaving the top fin portion exposed. At least a portion of the exposed top fin portion in the channel region is processed to form a sharpened tip profile at top of the fin. A gate having a gate dielectric and a metal gate electrode is formed over the substrate. The gate wraps around the channel region of the fin structure.

An alternating stack of layers of a first epitaxial semiconductor material and a second epitaxial semiconductor material is formed on a substrate. A fin stack is formed by patterning the alternating stack into a shape of a fin having a parallel pair of vertical sidewalls. After formation of a disposable gate structure and an optional gate spacer, raised active regions can be formed on end portions of the fin stack. A planarization dielectric layer is formed, and the disposable gate structure is subsequently removed to form a gate cavity. A crystallographic etch is performed on the first epitaxial semiconductor material to form vertically separated pairs of an upright triangular semiconductor nanowire and an inverted triangular semiconductor nanowire. Portions of the epitaxial disposable material are subsequently removed. After an optional anneal, the gate cavity is filled with a gate dielectric and a gate electrode to form a field effect transistor.

Devices and methods for forming a device are presented. The method includes providing a substrate prepared with at least a first region for accommodating an anti-fuse based memory cell. A fin structure is formed in the first region. The fin structure includes top and bottom fin portions and includes channel and non-channel regions defined along the length of the fin structure. An isolation layer is formed on the substrate. The isolation layer has a top isolation surface disposed below a top fin surface, leaving the top fin portion exposed. At least a portion of the exposed top fin portion in the channel region is processed to form a sharpened tip profile at top of the fin. A gate having a gate dielectric and a metal gate electrode is formed over the substrate. The gate wraps around the channel region of the fin structure.

A semiconductor device includes a drain, a source, a gate electrode, and a nanowire between the source and drain. The nanowire has a first section with a first thickness and a second section with a second thickness greater than the first thickness. The second section is between the first section and at least one of the source or drain. The first nanowire includes a channel when a voltage is applied to the gate electrode.

An alternating stack of layers of a first epitaxial semiconductor material and a second epitaxial semiconductor material is formed on a substrate. A fin stack is formed by patterning the alternating stack into a shape of a fin having a parallel pair of vertical sidewalls. After formation of a disposable gate structure and an optional gate spacer, raised active regions can be formed on end portions of the fin stack. A planarization dielectric layer is formed, and the disposable gate structure is subsequently removed to form a gate cavity. A crystallographic etch is performed on the first epitaxial semiconductor material to form vertically separated pairs of an upright triangular semiconductor nanowire and an inverted triangular semiconductor nanowire. Portions of the epitaxial disposable material are subsequently removed. After an optional anneal, the gate cavity is filled with a gate dielectric and a gate electrode to form a field effect transistor.