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

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 1 MeV Au ions after penetrating a Si₃N₄ foil with a thickness of ∼100 nm. The exiting Au ions are collected by a Si wafer located ∼14 mm 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 Si ₃N₄ 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 Si₃N ₄ foils induced by 1 MeV Au ion irradiation is observed with an average loss rate of ∼107 atoms/ion.