Measurement of Projected and Lateral Range Parameters for Low Energy Heavy Ions in Silicon by Rutherford Backscattering

Abstract

Range parameters for heavy ions implanted into silicon have been measured using Rutherford backscattering. The parameters measured were the projected range Rp and corresponding standard deviation ∆ Rp, and the standard deviation ∆ RL in lateral range. Projectile masses and energies were chosen to cover the range 0.005 < e < 0.5. Measured values of RP, ∆Rp and ∆RL, are greater than theoretical predictions based on LSS. For Rp and ∆RL the discrepancy is least (∌15%) as e → 0.5 but rises to ∌ 40 – 70% at low ɛ. The relative straggle, ∆Rp/Rp, is in good agreement with theory at low energies and is 30% larger at high energies. The relationship α p = 1.75 e2/3 is found to be a good approximation for the projected range for 0.02 < e < 0.5.