High mobility strained channels for fin-based nmos transistors

Abstract

Techniques are disclosed for incorporating high mobility strained channels into fin-based NMOS transistors (e.g., FinFETs such as double-gate, trigate, etc), wherein a stress material is cladded onto the channel area of the fin. In one example embodiment, a germanium or silicon germanium film is cladded onto silicon fins in order to provide a desired tensile strain in the core of the fin, although other fin and cladding materials can be used. The techniques are compatible with typical process flows, and cladding deposition can occur at a plurality of locations within typical process flow. In various embodiments, fins may be formed with a minimum width (or later thinned) so as to improve transistor performance. In some embodiments, a thinned fin also increases tensile strain across the core of a cladded fin. In some cases, strain in the core may be further enhanced by adding an embedded silicon epitaxial source and drain.