Silicon-germanium (SiGe) or silicon–carbon alloys (Si:C) are used as embedded stressors in silicon devices since they increase the channel strain and the performance as a result of the lattice mismatch. The strain properties of silicon with carbon doped on a relaxed SiGe virtual substrate are examined using reciprocal space mapping. Due to the ∼52% lattice mismatch between silicon and carbon, the silicon with a carbon-doped surface channel is under greater strain than it on a relaxed SiGe virtual substrate. This suggests that the carrier mobility could be significantly enhanced. The extracted electron mobility of a n-type metal-oxide-semiconductor field-effect transistor (MOSFET) device with 0.25% carbon shows the enhancement of 22% and 65% for the peak mobility and a large electric field (1 MV/cm), respectively.

The ~20% Id,sat improvement is demonstrated successfully on the Si and Ge n-FinFETs with the implement of D-SMT stressor for the first time, based on the optimization of dislocation angle and the understanding of crystal re-growth velocities along different surface planes and directions in Si and Ge. The mobility enhancement ratio with D-SMT stressor in Ge n-FinFET (37%) is found to be larger than it in the Si n-FinFET (30%). Ultra-high capping stress film (>3 GPa) is needed and is the must to modify the crystal re-growth velocities along the [100] and [110] directions for the dislocation angle optimization and the implement of D-SMT on the FinFET structure. The larger stress and mobility enhancement ratio are observed in the narrower gate width device, due to the effect of triple crystal re-growth directions on the FinFET structure.

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