Peculiar structure of X-ray standing wave lines of Si:As

X-ray standing wave (XSW) lines were measured for As-implanted Si wafers (Si:As) in order to investigate the annealing effect on local structure around As atoms. The observed XSW lines were spiral like and their patterns of an annealed and as-implanted Si:As samples were quite similar, though the EXAFS data of both samples showed different local structures. This result suggested that there existed stable mosaic crystalline phase in a certain region of Si wafer, which formed during As-implantation. The structural difference between the annealed and as-implanted Si:As samples was clarified by the XSW line measurements with highly angular resolution, resulting that the surfaces of the as-implanted Si:As sample were amorphous like and it crystallized by the annealing.