Argon Precursor Ion Implantation Used to Activate Boron Atoms in Silicon at Low Temperatures

The two-step implantation of argon precursor ion (Ar+) followed by boron ion (B+) in single crystalline silicon at room temperature is discussed to activate boron implanted region by post heating at 300 followed by 400°C. The implantation of Ar+ at a dose of 6.0 × 1013 cm-2 at 70 keV with a projected range Rp(Ar) of 80 nm followed by B+ at 1.0 × 1015 cm-2 and 15 keV with Rp(B) of 62 nm caused crystalline disordered states with the effective disordered amorphous depth Aeff of 32 nm, while the post heating of 300°C for 90 min followed by 400°C for 30 min markedly decreased Aeff to 1.8 nm. The effective recrystallization by the post heating promoted activation of doped region associated with decrease in the sheet resistivity to 189 Ω/sq by the post heating. The activation ratio was estimated as 0.33 under the assumption of a hole mobility of 50 cm2/Vs in the boron implanted region.