Shallow pn junction formed by in situ doping during selective growth of an embedded semiconductor alloy by a cyclic growth/etch deposition process

摘要

A silicon/carbon alloy may be formed in drain and source regions, wherein another portion may be provided as an in situ doped material with a reduced offset with respect to the gate electrode material. For this purpose, in one illustrative embodiment, a cyclic epitaxial growth process including a plurality of growth/etch cycles may be used at low temperatures in an ultra-high vacuum ambient, thereby obtaining a substantially bottom to top fill behavior.

主权项

1. A method of fabricating a field effect transistor (FET), the method comprising:
forming cavities in an active region adjacent to a gate electrode structure to a first depth by a first anisotropic etch process; modifying a surface layer at least at a side surface of said cavities; deepening said cavities so as to extend to a second depth by performing a second anisotropic etch process; forming a semiconductor alloy in said cavities by performing a selective epitaxial growth process; and introducing a dopant species into a deposition ambient of said epitaxial growth process at an advanced phase of said selective epitaxial growth process to form shallow drain and source regions.