Front stage process of a fully depleted silicon-on-insulator device and a structure thereof

摘要

The front-stage process of a fully depleted SOI device and the structure thereof are described An SOI substrate having an insulation layer and a crystalline silicon layer above the insulation layer is provided. An isolation layer is formed in the crystalline silicon layer and is connected to the insulation layer to define a first-type MOS active region. An epitaxial suppressing layer is formed above the crystalline silicon layer outside of the first-type MOS active region A second-type doped epitaxial silicon layer is selectively formed above the crystalline silicon layer in the first-type MOS active region. The second-type doped epitaxial layer is doped in-situ. An undoped epitaxial silicon layer is selectively formed above the second-type doped epitaxial silicon layer. The epitaxial suppressing layer is then removed.