80–100 keV Ar+, 200 keV Xe+, and 200 keV Hg+were implanted into Si3N4films under angles of 0°, 45°, 60°, and 75°. Both normal and oblique incidence Rutherford backscattering of 2.1 MeV He ions have been used to study tilted angle implantation, i.e., the lateral spread of Ar, Xe, and Hg ions in the Si3N4films. The results extracted are compared with the simulation of transport of ions in matter (TRIM’89 code). The experimental lateral spread seems to be in good agreement with the TRIM’89 prediction.