Depth of origin of sputtered particles under the oblique incidence of a primary ion beam

Abstract

A physical model and mathematical calculations of the maximum partial depths of origin of sputtered particles versus mass, energy, and the angle of incidence of ions bombarding a one-component amorphous target are presented. Calculations reveal that the maximum depth of origin of secondary particles depends on the primary-ion incidence angle, which attains the highest value at angles of 30°–60° relative to the normal to the sample surface. When the primary beam and the target material have identical parameters, the maximum depths of origin of light secondary particles exceed those of heavy ones. Secondary particles exhibit the isotope effect. For light elements (Li, Be, and B), a heavier isotope has a larger maximum depth of origin than a lighter one. In the case of heavy elements (e.g., Mo), a lighter isotope has a greater maximum depth of origin than a heavier one.