Semiconductor device having MOS varactor and methods for fabricating the same

摘要

In a method for manufacturing a semiconductor device, a gate electrode is formed in a first region. A silicide blocking layer is patterned such that a first gate spacer is formed on sidewalls of the gate electrode, and a silicide blocking layer pattern is formed in a second region. A lightly doped source/drain region is formed on surface of the first region. A second gate spacer is formed on sidewalls of the first gate spacer. A heavily doped source/drain region is formed on the surface of the first region. A silicide layer is formed on the gate electrode and the heavily doped source/drain region in the first region.