Angle-Dependent Implantation and Damage Characteristics of 60 keV Nitrogen Ions in Zirconium: A SRIM/TRIM Simulation Study

Abstract

The implantation geometry of energetic ions controls their penetration, reflection and collision-cascade morphology. Here, the influence of incidence angle on 60 keV nitrogen-ion implantation into zirconium was evaluated with the Monte Carlo Binary Collision Approximation implemented in SRIM/TRIM. For each angle (0°, 6°, 12°, 18° and 24°, measured from the surface normal), 100,000 incident ions were simulated using a zirconium displacement energy of 25 eV, lattice binding energy of 3 eV and surface binding energy of 6.33 eV. Increasing the angle from 0° to 24° reduced the longitudinal projected range from 102.9 to 96.8 nm (5.93%) and increased the number of backscattered ions from 7,966 to 10,223 (28.33%), corresponding to backscattering fractions of 7.97% and 10.22%. In contrast, the lateral projected range increased from 48.4 to 57.5 nm (18.80%), the radial range from 76.0 to 83.3 nm (9.61%), the lateral straggle from 59.8 to 70.4 nm (17.73%), and the radial straggle from 37.0 to 39.9 nm (7.84%). Vacancy production remained 314.7 vacancies per ion through 18° and decreased slightly to 311.4 vacancies per ion at 24°. These results show that modestly oblique incidence redistributes the collision cascade toward a shallower, laterally broader near-surface volume while increasing ion reflection, without substantially changing the gross displacement yield. The findings provide a quantitative basis for selecting implantation geometry in zirconium surface modification; however, experimental validation and crystal-aware simulations are required before inferring retained nitrogen concentration, phase formation or property enhancement.