Incorporation of tin in boron doped silicon for reduced deactivation of boron during post-laser-anneal rapid thermal processing

The supersaturated and metastable boron produced by laser anneal could deactivate during post-laser-thermal-cycles and lead to undesirable performance degradation. The effect of tin incorporation on the thermal stability of boron was studied for the first time and suppressed boron deactivation during post-laser-rapid-thermal-anneal was observed with tin coimplantation. High resolution x-ray diffraction measurement indicates that the tensile strain caused by a high boron concentration was reduced by the introduction of tin, which effectively reduces the strain energy and therefore, enhances the thermal stability of boron in post-laser-anneal rapid thermal processing.