| Popis: |
At low energy, large-angle multiple scattering influences the depth distribution of ions implanted into materials. Therefore, Monte Carlo codes have been widely used to calculate the depth distribution of implanted ions. However, these codes give results which can sometimes be significantly different from experimental measurements. In addition, during the implantation of polymers and hydrogenated carbon layers, a given quantity of hydrogen atoms can be released, which changes the stopping power and influences the depth distribution. Finally, the local accumulation of electric charges also modify the ion distribution. In order to quantify the effect of each contribution, samples of hydrogenated carbon and polystyrene (PS) have been implanted with low energy (0.4–1.6 keV) deuterium ions. An experimental procedure is described which takes into account the effects mentioned above in order to measure the mean ranges (Rp) and standard deviations (σ) of the depth distributions by means of the ERD ExB technique. Results show that both the Rp and σ decrease with the quantity of hydrogen in the materials. The experimental data in PS films are not in good agreement with the computer simulations while those in the a-C:H layers are well reproduced using TRIM.SP with the krypton–carbon interatomic potential and the Oen–Robinson electronic energy loss model. Comparison of the experimental D depth profiles in PS with the D depth profiles and the damage profiles as simulated by TRIM.SP and with the H loss profile following the D implantation suggests that the implanted D could be trapped in the damage profile induced by the implantation. |
Full Text from ScienceDirect