The dependence on the angle of incidence of the steady state sputter yield of silicon bombarded by oxygen ions

The increased dependence of the sputter yield of silicon on the angle of incidence under oxygen ion bombardment, as compared to argon ion bombardment, observed during a SIMS analysis is discussed. Taking into account that the sputter yield depends on the implanted oxygen concentration, a relation is derived between the steady state sputter yield and the implanted oxygen surface concentration for different angles of incidence. Since this relation is in itself insufficient to determine the steady state values of the sputter yield and the surface concentration actually obtained, a graphical method is used to combine it with a second one, viz. the dependence of the momentary sputter yield on the momentary surface concentration. Measurements of the steady state sputter yield of silicon, bombarded by oxygen ions in the lower keV range at different angles of incidence, agree with the predicted values. (author)