SEMICONDUCTOR STRUCTURE AND ITS TYPE, AND METHOD (STRUCTURE AND METHOD FOR FORMING MULTILAYER EMBEDDED STRESSOR)

摘要

PROBLEM TO BE SOLVED: To provide a multilayer embedded stressor which is used in a semiconductor structure causing deformation in a device channel area and has a gradual dopant distribution structure.

SOLUTION: This multilayer stressor is formed in a portion of a semiconductor structure where a source/drain area is generally positioned. This multilayer stressor comprises a first co-epitaxial semiconductor layer not doped or doped at a low concentration and a second epitaxial semiconductor layer doped at higher concentration than the first epitaxial semiconductor layer. Each of the first and second epitaxial layers has an identical lattice constant. The lattice constant differs from that of a substrate where each semiconductor layer is embedded. A structure including this multilayer embedded stressor ensures a good balance between an adjacent stress and a short channel effect and eliminates or substantially reduces any defects which generally occur during deeper source/drain area formation.

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