A technique for forming a semiconductor device is provided. Sacrificial mandrels are formed over a hardmask layer on a semiconductor layer. Spacers are formed on sidewalls of the sacrificial mandrels. The sacrificial mandrels are removed to leave the spacers. A masking process leaves exposed a first set of spacers with a second set protected. In response to the masking process, a first fin etch process forms a first set of fins in the semiconductor layer via first set of spacers. The first set of fins has a vertical sidewall profile. Another masking process leaves exposed the second set of spacers with the first set of spacers and the first set of fins protected. In response to the other masking process, a second fin etch process forms a second set of fins in semiconductor layer using the second set of spacers. The second set of fins has a trapezoidal sidewall profile.

A complementary metal oxide semiconductor (CMOS) device includes a p-channel metal oxide semiconductor (PMOS) transistor unit and an n-channel metal oxide semiconductor (NMOS) transistor unit. A semiconductor layer of the PMOS transistor unit between source and drain electrodes thereof is divided into a first tapered region having an ion concentration of CP/e and a first flat region having an ion concentration of CP/f. A semiconductor layer of the NMOS transistor unit between source and drain electrodes thereof is divided into a second tapered region having an ion concentration of CN/e, a second flat region having an ion concentration of CN/f2 and a third flat region located between the second tapered region and second flat region and having an ion concentration of CN/f1, wherein the ion concentrations have a relationship of CP/e<CP/f<CN/f2<CN/e<CN/f1.

In one example, a method for fabricating a semiconductor device includes forming a mandrel comprising silicon. Sidewalls of the silicon are orientated normal to the <111> direction of the silicon. A nanowire is grown directly on at least one of the sidewalls of the silicon and is formed from a material selected from Groups III-V. Only one end of the nanowire directly contacts the silicon.

During a physical vapor deposition (PVD) process, the ion energy of a depositing species is controlled. By varying the ion energy throughout the process, the degree of conformality of the deposited layer over three-dimensional structures, including the extent to which the deposited layer merges between adjacent structures can be controlled.

A method for forming nanowires includes forming a plurality of epitaxial layers on a substrate, the layers including alternating material layers with high and low Ge concentration and patterning the plurality of layers to form fins. The fins are etched to form recesses in low Ge concentration layers to form pillars between high Ge concentration layers. The pillars are converted to dielectric pillars. A conformal material is formed in the recesses and on the dielectric pillars. The high Ge concentration layers are condensed to form hexagonal Ge wires with (111) facets. The (111) facets are exposed to form nanowires.

Techniques for reducing the specific contact resistance of metal-semiconductor (group IV) junctions by interposing a monolayer of group V or group III atoms at the interface between the metal and the semiconductor, or interposing a bi-layer made of one monolayer of each, or interposing multiple such bi-layers. The resulting low specific resistance metal-group IV semiconductor junctions find application as a low resistance electrode in semiconductor devices including electronic devices (e.g., transistors, diodes, etc.) and optoelectronic devices (e.g., lasers, solar cells, photodetectors, etc.) and/or as a metal source and/or drain region (or a portion thereof) in a field effect transistor (FET). The monolayers of group III and group V atoms are predominantly ordered layers of atoms formed on the surface of the group IV semiconductor and chemically bonded to the surface atoms of the group IV semiconductor.

The reliability of a transistor including an oxide semiconductor is improved. The transistor in a semiconductor device includes a first oxide semiconductor film over a first insulating film, a gate insulating film over the first oxide semiconductor film, a second oxide semiconductor film over the gate insulating film, and a second insulating film over the first oxide semiconductor film and the second oxide semiconductor film. The first oxide semiconductor film includes a channel region overlapping with the second oxide semiconductor film, a source region and a drain region each in contact with the second insulating film. The channel region includes a first layer and a second layer in contact with a top surface of the first layer and covering a side surface of the first layer in the channel width direction. The second oxide semiconductor film has a higher carrier density than the first oxide semiconductor film.

A highly reliable semiconductor device including, an oxide semiconductor is provided. Provided is a semiconductor device including an oxide semiconductor layer, an insulating layer in contact with the oxide semiconductor layer, a gate electrode layer overlapping with the oxide semiconductor layer, and a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer. The oxide semiconductor layer includes a first region having a crystal whose size is less than or equal to 10 nm and a second region which overlaps with the insulating layer with the first region provided therebetween and which includes a crystal part whose c-axis is aligned in a direction parallel to a normal vector of the surface of the oxide semiconductor layer.

A retention circuit provided in a logic circuit enables power gating. The retention circuit includes a first terminal, a node, a capacitor, and first to third transistors. The first transistor controls electrical connection between the first terminal and an input terminal of the logic circuit. The second transistor controls electrical connection between an output terminal of the logic circuit and the node. The third transistor controls electrical connection between the node and the input terminal of the logic circuit. A gate of the first transistor is electrically connected to a gate of the second transistor. In a data retention period, the node becomes electrically floating. The voltage of the node is held by the capacitor.

A structure such as an integrated circuit device is described having a line of material with critical dimensions which vary within a distribution substantially less than that of a mask element, such as a patterned resist element, used in manufacturing the line of material.