Strain additivity in III-V channels for CMOSFETs beyond 22nm technology node

For the first time strain additivity on III-V using prototypical (100) GaAs n- and p-MOSFETs is studied via wafer bending experiments and piezoresistance coefficients are extracted and compared with those for Si and Ge MOSFETs. Further understanding of these results is obtained by using multi-valley conduction band model for n-MOS and performing k.p simulations for p-MOS. For GaAs n-MOSFET, uniaxial tensile stress is shown to enhance performance only for small stresses biaxial tensile stress is shown to be more beneficial. Importantly uniaxial compressive stress is beneficial for GaAs pMOSFETs and the piezoresistance effect is much larger than that seen for Si MOSFETs along the <110> channel direction. This works shows that intrinsic mobility and stress induced mobility enhancement are key knobs for scaling of III-V CMOSFETs.