Selective Epitaxial Phosphorus-Doped SiGe Layers for Short-Channel Effect Reduction

Epitaxially grown silicon germanium layers are utilized in very high performance short channel MOSFETs. To reduce short-channel effects, the substrate doping concentration must be increased at the edges of the source and drain. These regions commonly called halos are typically created by ion implantation but the precise positioning of the dopant is a challenge. As devices with embedded SiGe source/drain regions continue to scale, the proximity of the source and drain regions to each other increases the challenge of proper halo placement. This work proposes incorporation of halo placement into the epitaxial deposition process so that dopants are automatically placed where they are needed.