Semiconductor device and fabrication method thereof
AssigneeSemiconductor Manufacturing International (Shanghai) Corporation
InventorWeiHai BU
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Abstract
A semiconductor device fabrication method is provided in which recesses are formed at source/drain positions in the substrate, removable sidewalls are formed on side walls of the recess, and the recesses then are etched to form Sigma shaped recesses. Selective epitaxial growth of substantially un-doped SiGe in the Sigma shaped recesses is performed, and the Sigma shaped recesses close to the surface of the substrate can be protected from epitaxial growth by the removable sidewalls. Epitaxial growth of SiGe doped with a P-type impurity can be performed in the Sigma shaped recesses after removing the sidewalls.
Claims12
A semiconductor device fabrication method comprising:
- providing a substrate on which a gate structure is formed;
- etching the substrate to form a recess at a source/drain position in the substrate;
- forming removable sidewalls on side walls of the recess;
- etching the recess to form a Sigma shaped recess;
- performing selective epitaxial growth of substantially un-doped SiGe in the Sigma shaped recess;
- removing the removable sidewalls;
- performing epitaxial growth of SiGe doped with P-type impurities in the Sigma shaped recess.
A semiconductor device comprising:
- a gate structure formed on a substrate of the semiconductor device;
- a Sigma shaped recess formed in the substrate beside the gate structure;
- a layer of substantially un-doped SiGe epitaxially grown on the inner surface of the Sigma shaped recess;
- and
- a bulk section of SiGe doped with P-type impurities epitaxially grown on the layer of substantially un-doped SiGe within the Sigma shaped recess,
- wherein the layer of substantially un-doped SiGe is located within the Sigma shaped recess at a predetermined depth from a surface of the substrate.
Dependencies are inferred from the claim text.