Effects of ion implantation damage on elevated source/drain formation for ultrathin body silicon on insulator metal oxide semiconductor field-effect transistor

For high-speed and low-power performance, ultrathin body (UTB) silicon on insulator (SOI) metal oxide semiconductor field-effect semiconductors (MOSFETs) with an elevated source/drain (ESD) have been investigated using selectively epitaxial growth (SEG) technology. In this work, we found that the morphology of a SEG layer on an ultrathin Si film and the crystallinity of the top Si film are strongly dependent on ion implantation damage. The morphology and surface roughness of SEG layers were investigated by field emission scanning electron microscopy (FE-SEM) and the crystallinities of the top silicon films with and without ion implantation were characterized by atomic force microscopy (AFM) and Rutherford backscattering spectroscopy (RBS), respectively. Furthermore, to suppress ion implantation damage, a SEG layer was formed before ion implantation for source drain extension (SDE) formation by the sacrificial sidewall spacer method. As results, UTB SOI-MOSFETs with a flat ESD were successfully fabricated by the proposed method.