| abstract |
A semiconductor device includes a first NMOS device with a first threshold voltage and a second NMOS device with a second threshold voltage. The first NMOS device includes a first gate structure over a semiconductor substrate, first source/drain (S/D) regions in the semiconductor substrate and adjacent to opposite edges of the first gate structure. The first S/D regions are free of dislocation. The second NMOS device includes a second gate structure over the semiconductor substrate, second S/D regions in the semiconductor substrate and adjacent to opposite edges of the second gate structure, and a dislocation in the second S/D regions. |