Random and channeling stopping powers and charge-state distributions in silicon for 0.2–1.2 MeV/u positive heavy ions

Abstract

Stopping powers and equilibrium charge-state distributions for 0.2--1.2 MeV/u ${}^{7}\mathrm{Li},$ ${}^{11}\mathrm{B},$ ${}^{12}\mathrm{C},$ ${}^{14}\mathrm{N},$ ${}^{16}\mathrm{O},$ ${}^{31}\mathrm{P},$ and ${}^{35}\mathrm{Cl}$ ions, measured in transmission of a 780 nm crystalline silicon foil, are reported. Using a high-resolution electrostatic analyzer, ion energy loss was determined within \ifmmode\pm\else\textpm\fi{}3%. The thickness of the Si foil was measured independently by Rutherford backscattering and SEM with an uncertainty of about 3--4 %. The random and channeling stopping powers were estimated within approximately \ifmmode\pm\else\textpm\fi{}5%, fitted using an empirical expression, and compared with the TRIM95 database. Resulting differences between the fitted and the empirical stopping powers were in the range of 5--15%, depending on ion species and incident beam energy. The equilibrium charge fractions were determined within about \ifmmode\pm\else\textpm\fi{}4% for most cases. At small angles to the {110} plane, the energy-loss spectra exhibit a multiple peak structure, primarily due to trajectory selection.