High performance transistors with SiGe strain

摘要

A preferred embodiment of the invention comprises a semiconductor device having stress in the source/drain channel. The device comprises a substrate having a lattice constant greater than or equal to silicon and a first layer on the substrate, wherein the first layer has a lattice constant greater than the substrate. Alternative embodiments include a second layer formed on the first layer. The second layer has a lattice constant less than the first layer. Preferably, the second layer underlies a gate electrode and at least a portion of a sidewall spacer. Still other embodiments include a recess for inducing stress in the source/drain channel.