FinFET/Tri-Gate Channel Doping for Multiple Threshold Voltage Tuning

摘要

An embodiment method of controlling threshold voltages in a fin field effect transistor (FinFET) includes forming a dummy gate over a central portion of a fin, the central portion of the fin disposed between exterior portions of the fin unprotected by the dummy gate, removing the exterior portions of the fin and replacing the exterior portions of the fin with an epitaxially-grown silicon-containing material, applying a spin-on resist over the dummy gate and the epitaxially-grown silicon-containing material and then removing the spin-on resist over the hard mask of the dummy gate, etching away the hard mask and a polysilicon of the dummy gate to expose a gate oxide of the dummy gate, the gate oxide disposed over the central portion of the fin, and implanting ions into the central portion of the fin through the gate oxide disposed over the central portion of the fin.