this invention teaches methods of combining ion implantation steps with in situ or ex situ heat treatments to avoid and / or minimize implant - induced amorphization regions in fets in ultrathin silicon on insulator layers ) and implant - induced plastic relaxation of strained s / d regions . in a first embodiment , ion implantation is combined with in situ heat treatment by performing the ion implantation at elevated temperature . in a second embodiment , ion implantation is combined with ex situ heat treatments in a “ divided - dose - anneal - in - between ” scheme that avoids the need for tooling capable of performing hot implants .