Highly tensile strained silicon-carbon alloys epitaxially grown into recessed source drain areas of NMOS devices

摘要

Growth of high quality Si_(1-y-z)C_yP_z (SiCP) with high substitutional carbon levels has been demonstrated. Growth rates up to 82 nm min~(-1) (at 550℃) led to films incorporating up to 3.6% substitutional carbon [C]vl according to Vegard's law (VL) or 2.8% [C]_(KB) after Kelieres/Berti (KB). The films were fully strained with no sign of relaxation and displayed stress well above 2 GPa. Optionally, these films can be heavily doped with P, which then results in resistivities as low as 0.5 mΩ cm. The α/epi growth rate ratio was optimized to 1. This high throughput SiCP epitaxial growth process is an excellent candidate to be combined with a selective etch process. Used with repeated deposition/etch cycles, the final result will be identical to a true selective epitaxial growth process, but without any loading effect on [C] or [P] due to the blanket deposition steps.