Strained silicon

More recent methods of inducing strain include doping the source and drain with lattice mismatched atoms such as germanium and carbon.

[2] Germanium doping of up to 20% in the P-channel MOSFET source and drain causes uniaxial compressive strain in the channel, increasing hole mobility.

Carbon doping as low as 0.25% in the N-channel MOSFET source and drain causes uniaxial tensile strain in the channel, increasing electron mobility.

Covering the NMOS transistor with a highly stressed silicon nitride layer is another way to create uniaxial tensile strain.

[5] In 2005, Intel was sued by AmberWave company for alleged patent infringement related to strained silicon technology.