295 results about "Semiconductor alloys" patented technology

In a transistor, a strain-inducing semiconductor alloy, such as silicon / germanium, silicon / carbon and the like, may be positioned very close to the channel region by providing gradually shaped cavities which may then be filled with the strain-inducing semiconductor alloy. For this purpose, two or more “disposable” spacer elements of different etch behavior may be used in order to define different lateral offsets at different depths of the corresponding cavities. Consequently, enhanced uniformity and, thus, reduced transistor variability may be accomplished, even for sophisticated semiconductor devices.

Techniques for the fabrication of field-effect transistors (FETs) having nanowire channels are provided. In one aspect, a method of fabricating a FET is provided comprising the following steps. A substrate is provided having a silicon-on-insulator (SOI) layer. At least one nanowire is deposited over the SOI layer. A sacrificial gate is formed over the SOI layer so as to cover a portion of the nanowire that forms a channel region. An epitaxial semiconductor material is selectively grown from the SOI layer that covers the nanowire and attaches the nanowire to the SOI layer in a source region and in a drain region. The sacrificial gate is removed. An oxide is formed that divides the SOI layer into at least two electrically isolated sections, one section included in the source region and the other section included in the drain region. A gate dielectric layer is formed over the channel region. A gate is formed over the channel region separated from the nanowire by the gate dielectric layer. A metal-semiconductor alloy is formed over the source and drain regions.

A field effect transistor (“FET”) is provided which includes a gate stack overlying a single-crystal semiconductor region of a substrate, a pair of first spacers disposed over sidewalls of said gate stack, and a pair of regions consisting essentially of a single-crystal semiconductor alloy which are disposed on opposite sides of the gate stack. Each of the semiconductor alloy regions is spaced a first distance from the gate stack. The source region and drain region of the FET are at least partly disposed in respective ones of the semiconductor alloy regions, such that the source region and the drain region are each spaced a second distance from the gate stack by a first spacer of the pair of first spacers, the second distance being different from the first distance.