Reordering of implanted amorphous Si layers with low temperature RTA

Reordering of ion implanted amorphous Si layers with rapid thermal annealing (RTA) was investigated with spectroscopic ellipsometry. The reordering rates in the temperature range of 450-550°C by RTA agree well with earlier studies using conventional furnace annealing. The reordering rate for a lower dose (As 3×10¹⁴ cm^-2 ) was found to be faster than that for a higher dose (As 4×10¹⁵ cm^-2), perhaps because of higher concentrations of knock-on implanted oxygen. The amorphous layer thickness for Ge ion implantation was same as that for equivalent energy and dose As ion implantation. However the reordering rate for Ge implanted layers was much slower than that of As implantation, almost same as that for Si ion implantation. In the case of 3×10¹⁴ cm^-2 As dose high reordering rate was observed for a thin (7 nm) layer as well as reordering at temperature, lower than 450°C. It was due to the roughness of a wide transient layer and did not occur in case of high dose As implantation; 4×10¹⁵ cm^-2 because of a narrow transient layer