High Dose Rate Effect of Focused-Ion-Beam Boron Implantation into Silicon

The effect of high-dose-rate, 16 keV focused-ion-beam (FIB) B+ implantation into Si has been investigated as a function of current density and beam-scan speed. It is shown by µ-RHEED (micro-probe reflection high-energy electron diffraction) observation that the increase in electrical activation of implanted B atoms at such low temperature annealing as 600°C closely correlated with the increase in amorphous zones produced. It is also found that continuous amorphous layer formation occurs with a 1–2×1015 ions/cm2 (one order lower than for conventional implantation) when both implantation conditions of high current density and slow scan speed (e.g. 20 mA/cm2 and 6×10-3 cm/s) are satisfied. The reason for amorphous zone formation enhancement by FIB implantation is discussed.