| abstract |
A semiconductor device includes a substrate, a gate structure, a spacer, and a plurality of hyper-sigma (Σ) shaped epitaxial stressors. The substrate includes a first semiconductor material, and the hyper-Σ shaped epitaxial stressors include the first semiconductor material and a second semiconductor material. A lattice constant of the second semiconductor material is different from a lattice constant of the first semiconductor material. The hyper-Σ shaped epitaxial stressors respectively include a first portion, a second portion and a neck physically connecting the first portion and the second portion. The first portion includes a pair of first tips pointing toward the gate structure in a cross-sectional view. The second portion includes a pair of second tips pointing toward the gate structure in the cross-sectional view. The neck includes a first slanted surface in the first portion and a second slanted surface in the second portion. |