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 R_p(Ar) of 80 nm followed by B⁺ at 1.0 × 10¹⁵ cm^-2 and 15 keV with R_p(B) of 62 nm caused crystalline disordered states with the effective disordered amorphous depth A_eff of 32 nm, while the post heating of 300°C for 90 min followed by 400°C for 30 min markedly decreased A_eff 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.