A method includes receiving a substrate; forming on the substrate a semiconductor fin; an isolation structure surrounding the semiconductor fin; and first and second dielectric fins above the isolation structure and sandwiching the semiconductor fin; depositing a spacer feature filling spaces between the semiconductor fin and the first and second dielectric fins; performing an etching process to recess the semiconductor fin, resulting in a trench between portions of the spacer feature; and epitaxially growing a semiconductor material in the trench.