MONOLAYER DOPANT EMBEDDED STRESSOR FOR ADVANCED CMOS

摘要

Semiconductor structures are disclosed that have embedded stressor elements therein. The disclosed structures include an FET gate stack 18 located on an upper surface of a semiconductor substrate 12. The FET gate stack includes source and drain extension regions 28 located within the semiconductor substrate at a footprint of the FET gate stack. A device channel 40 is also present between the source and drain extension regions and beneath the gate stack. The structure further includes embedded stressor elements 34 located on opposite sides of the FET gate stack and within the semiconductor substrate. Each of the embedded stressor elements includes a lower layer of a first epitaxy 36 doped semiconductor material having a lattice constant that is different from a lattice constant of the semiconductor substrate and imparts a strain in the device channel, and an upper layer of a second epitaxy 38 doped semiconductor material located atop the lower layer. The lower layer of the first epitaxy doped semiconductor material has a lower content of dopant as compared to the upper layer of the second epitaxy doped semiconductor material. The structure further includes a monolayer of dopant located within the upper layer of each of the embedded stressor elements. The monolayer of dopant is in direct contact with an edge of either the source extension region or the drain extension region.