SiGe strain relaxed buffer for high mobility devices and a method of fabricating it

摘要

The invention relates to a semiconductor device comprising a semiconductor substrate and having on its top at least a Thin Strain Relaxed Buffer, consisting of three layers, characterised in that all three layers of said Thin Strain Relaxed Buffer have an essentially constant Ge concentration, said three layers being : a first epitaxial layer of Si1-xGex, x being the Ge concentration a second epitaxial layer of Si1-xGex: C on said first epitaxial layer, the amount of C being at least 0.3 % a third epitaxial layer of Si1-xGex on said second layer.