Method for growing multiple layers of source drain epitaxial silicon in fdsoi process

Abstract

The application provides a method for growing multiple layers of source drain epitaxial silicon in an FDSOI process, forming a buried oxide layer on the substrate, and then forming an SOI layer on the buried oxide layer; forming a gate on the SOI layer, wherein a source drain region is provided on two sides of the gate; forming an undoped epitaxial layer on the SOI layer of the source drain region; forming a first doped epitaxial layer on the undoped epitaxial layer; forming a second doped epitaxial layer on the first doped epitaxial layer; and cleaning the substrate with deionized water. In the present application, the epitaxial silicon is changed from a single layer structure to a multilayer structure, wherein undoped epitaxial silicon can effectively prevent ion diffusion, and middle-highly doped epitaxial silicon and highly doped epitaxial silicon can significantly reduce source drain resistance and improve device performance.