Predicting range profiles of low-energy ͑0.1-10 keV/amu͒ ions implanted in materials is a long-standing problem of considerable theoretical and practical interest. We combine here the best available method for treating the nuclear slowing down, namely a molecular-dynamics range calculation method, with a method based on density-functional theory to calculate electronic slowing down for each ion-target atom pair separately. Calculation of range profiles of technologically important dopants in Si shows that the method is of comparable accuracy to previous methods for B, P, and As implantation of Si, and clearly more accurate for Al implantation of Si.Calculating the force which slows down energetic ions traversing in materials ͑the stopping power͒ is a longstanding problem of considerable theoretical and practical interest. 1-3 While the stopping power caused by collisions between an ion and atoms can now be predicted very accurately, 4-6 there is still uncertainty in how the stopping caused by collisions between an ion and electrons ͑electronic stopping͒ should be calculated for ion velocities below the Bohr velocity ͑namely at energies of the order of 0.1-10 keV/amu͒. This is an especially pressing problem for obtaining range profiles for dopants implanted in crystal channel directions in semiconductors, since on one hand the uncertainties are particularly large in this case and on the other hand this case is important for the microelectronics industry.The most common approach for obtaining stopping powers is to first derive a stopping power for a proton in a material, and then use a scaling law to obtain the stopping power of heavier ions. To obtain the stopping power of the proton, the most popular approach is to use models 7,8 based on the scattering phase shifts for Fermi-surface electrons. The phase shifts are determined within the density-functional theory ͑DFT͒ ͑Ref. 9͒ for a proton embedded in a homogeneous electron gas. 10,11 This approach has proven successful for some technologically important ion-target combinations, such as B-Si, P-Si, and As-Si, 12,5,13 but leads into severe difficulties ͑a physically unjustified parameter value͒ for the case of Al-Si. 5 However, the original model with self-consistently determined phaseshifts offers another, frequently overlooked, approach to obtain stopping powers for heavy ions. Instead of using scaling laws, it is possible to explicitly calculate phase shift factors for any given ion-target atom combinations. The phase shift factors can be calculated directly from DFT, so this approach does not use any empirical or fitted input factors.Another noteworthy approach to predicting the electronic stopping is the local plasma approximation. However, this model does not presently treat channeling anisotropies in the electron distribution, 14 and hence is not applicable here.In this paper, we combine the best available simulations methods for calculating ion range profiles with electronic stopping powers derived from realistic three-dimensional charge distributions of t...
