This invention adds to the art of replacement source-drain cMOS
transistors. Processes may involve etching a recess in the substrate
material using one equipment set, then performing deposition in another.
Disclosed is a method to perform the etch and subsequent deposition in
the same reactor without atmospheric exposure. In-situ etching of the
source-drain recess for replacement source-drain applications provides
several advantages over state of the art ex-situ etching. Transistor
drive current is improved by: (1) Eliminating contamination of the
silicon-epilayer interface when the as-etched surface is exposed to
atmosphere and (2) Precise control over the shape of the etch recess.
Deposition may be done by a variety of techniques including selective and
non-selective methods. In the case of blanket deposition, a measure to
avoid amorphous deposition in performance critical regions is also
presented.