Tensile Strained Selective Silicon Carbon Alloys for Recessed Source Drain Areas of Devices

Si 1-y C y films grown lattice matched into recessed source drain areas can produce a tensile strained Silicon channel, which in turn will enhance electron mobility. We demonstrate a Cyclical Deposition Etch (CDE) process that consists of a nonselective deposition, (epitaxial growth over the exposed crystalline Silicon areas of the source and drain and amorphous (a) or polycrystalline deposition over the dielectric areas) together with a subsequent selective removal of a-material from the insulator, with negligible removal of epitaxial material from source and drain areas. To make such an approach production worthy, two requirements are essential: 1) a high growth rate (GR) with a low a/epi GR ratio, and 2) a high etch rate (ER) with a high a/epi ER ratio. We focus on the integration and defect formation aspect of our CDE process on patterned substrates.