METHOD FOR FABRICATING A QUASI-SOI SOURCE-DRAIN MULTI-GATE DEVICE

The present invention discloses a method for fabricating a quasi SOI source-drain multi-gate device, belonging to a field of manufacturing ultra large scale integrated circuit, the method comprises in sequence the following steps of: forming a Fin strip-shaped active region on a first semiconductor substrate; forming a STI isolation layer; depositing a gate dielectric layer and a gate material layer, forming a gate stack structure; forming a doped structure of a source-drain extension region; forming a recessed source-drain structure; forming a quasi SOI source-drain isolation layer; in-situ doping an epitaxial source and drain of a second semiconductor material and performing annealing for activating; removing a dummy gate and performing a deposition of a high k metal gate again; and forming a contact and a metal interconnection.