Transversal range straggling of 40 keV–2 MeV tungsten ions implanted in SiO 2

Abstract

This paper presents an experimental investigation of transversal range straggling of tungsten ions implanted in SiO 2 for a wide incident-ion-energy level of 40 keV–2 MeV. Tungsten ions were implanted into SiO 2 films tilted by angles of 7° and 55° with respect to the axis normal to the specimen for each incident-ion energy. The depth profiles of implanted tungsten ions were measured and fitted by using secondary ion mass spectrometry (SIMS) and Gaussian distribution, respectively. The measured values of projected range ( R p), longitudinal range straggling ( ΔR p) and transversal range straggling ( ΔR t) were determined from the corresponding Gaussian-fitted distributions of 7° and 55° implants along with Furukawa and Matsumura's method. The calculated values of R p, ΔR p and ΔR t yielded by the SRIM Monte-Carlo simulation code are also presented herein for comparison. It was found that the calculated values of R p, ΔR p and ΔR t agreed to the corresponding measured values within (on average) 19%, 21% and 14%, respectively. The discrepancies between the calculated and measured values of both ΔR p and ΔR t become significant at rather low incident-ion energies.