Stress simulations for optimal mobility group IV p- and nMOS FinFETs for the 14 nm node and beyond

Calculations of stress enhanced mobilities are performed for n- and p-FinFETs with both Si and Ge channels for the 14 nm node and beyond. Relaxed Ge p-FinFETs and even Ge with a GeSn5% source / drain stressor cannot outperform strained Si. However, growing the Ge channel strained on a SiGe75% strain relaxed buffer (SRB) provides a 49% mobility boost over strained Si. For Si n-FinFETs, SRB mobility boost is also possible, with Si on a SiGe 25% SRB improving mobility by 83%. Addition of a Si:C 2% S/D stressor increases that benefit to 109%. For Ge n-FinFETs, relaxed channels outperform strained Si by 120%, owing primarily to the 6× increase in fin sidewall mobility. Adding a SiGe 75% S/D stressor increases that benefit to 210%. In general, the SRB stressors have excellent scalability to future nodes. TCAD trends are qualitatively confirmed by Nano-Beam Diffraction.