Delta monolayer dopants epitaxy for embedded source/drain silicide

Abstract

Semiconductor structures are disclosed that have embedded stressor elements therein. The disclosed structures include at least one FET gate stack located on an upper surface of a semiconductor substrate. The at least one FET gate stack includes source and drain extension regions located within the semiconductor substrate at a footprint of the at least one FET gate stack. A device channel is also present between the source and drain extension regions and beneath the at least one gate stack. The structure further includes embedded stressor elements located on opposite sides of the at least one FET gate stack and within the semiconductor substrate. Each of the embedded stressor elements includes, from bottom to top, a first layer of a first epitaxy 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, a second layer of a second epitaxy doped semiconductor material located atop the first layer, and a delta monolayer of dopant located on an upper surface of the second layer. The structure further includes a metal semiconductor alloy contact located directly on an upper surface of the delta monolayer.