Method of forming an extremely thin semiconductor insulator (ETSOI) FET having a stair-shaped raised source/drain

摘要

A MOSFET device is formed on top of a semiconductor-on-insulator (SOI) substrate having a semiconductor layer with a thickness ranging from 3 nm to 20 nm. A stair-shape raised extension, a raised source region and a raised drain region (S/D) are formed on top of the SOI substrate. The thinner raised extension region abuts at a thin gate sidewall spacer, lowering the extension resistance without significantly increasing the parasitic resistance. A single epitaxial growth forms the thinner raised extension and the thicker raised S/D preferably simultaneously, reducing the fabrication cost as well as the contact resistance between the raised S/D and the extension. A method of forming the aforementioned MOSFET device is also provided.