Hydrogen plasma irradiation and postannealing effects on crystalline quality at vicinal Si 100/surface

Relationships between density of total incident hydrogen ions and full peak width at half maximum FWHM.at 400. diffraction spot in reflection high-energy electron diffraction RHEED.from vicinal Si 100.surface during plasma irradiation and postannealing are first reported. At the density of total incident hydrogen ions of 6.0=1014 ionsrcm2, the FWHM, which is normalized by that before plasma irradiation, is almost saturated at 1.8. No damaged layer and no defect are observed in cross-sectional transmission electron microscopic XTEM.images. On the other hand, at the density of 3.6=1015 ionsrcm2, the normalized FWHM is slightly increased to 1.9. However, the drastic degradation of surface crystalline quality, a uniform 50-nm thick damaged layer and a lot of extended planar defects, is observed in XTEM images. During postannealing of Si wafer irradiated at the density of 6.0=1014 ionsrcm2, the FWHM drastically decreases between 7008C and 8008C. Considering the causes of FWHM broadening and thermal stabilities of defects and disordered lattice, it is considered that this drastic improvement of FWHM is caused by annihilation of Si point defects and rearrangement of disordered lattice at Si surface. q2000 Elsevier Science B.V. All rights reserved.