Abstract
Various ion fluences together with different post-annealing sequences were performed to investigate the shallow-junction characteristics produced by 20 keV BF2+ molecular ions implanted into silicon. The ion fluences under investigation were 5 × 10 14 and 2 × 10 15 cm -2 . Post-annealing methods consisted of low-temperature furnace annealing (FA) at 550 °C for 1 h and high-temperature rapid thermal annealing (RTA) at 1050 °C for 10 s. The shallow-junction characteristics were analyzed using secondary ion mass spectrometry (SIMS), Rutherford backscattering spectrometry with channeling (RBS/C), transmission electron microscopy (TEM) and a four-point probe. The results revealed that the junction depth (x j ) of the FA + RTA annealing sequence was shallower than that of RTA + FA in both ion fluences. However, the sheet resistance (R s ) of FA + RTA was lower than that of RTA + FA in the 2 × 10 15 cm -2 specimen, while just the opposite is true in the 5 × 10 14 cm -2 specimen. It is concluded that FA + RTA, leading to a smaller x j R s , is a better two-step post-annealing sequence compared to RTA + FA for both ion fluences.