Angular distribution and recoil effect for 1 MeV Au+ ions through a Si3N4 thin foil

Abstract

The Stopping and Range of Ions in Matter (SRIM) code has been widely used to predict nuclear stopping power and angular distribution of ion–solid collisions. However, experimental validation of the predictions is insufficient for slow heavy ions in nonmetallic compounds. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) is applied to determine the angular distribution of 1MeV Au ions after penetrating a Si3N4 foil with a thickness of ∼100nm. The exiting Au ions are collected by a Si wafer located ∼14mm behind the Si3N4 foil, and the resulting 2-dimensional distribution of Au ions on the Si wafer is measured by ToF-SIMS. The SRIM-predicted angular distribution of Au ions through the Si3N4 thin foil is compared with the measured results, indicating that SRIM slightly overestimates the nuclear stopping power by up to 10%. In addition, thickness reduction of the suspended Si3N4 foils induced by 1MeV Au ion irradiation is observed with an average loss rate of ∼107atoms/ion.