A method is given to obtain an absolute calibration of the ion and evaporant fluxes in an ion-beam-assisted deposition system based upon a Kaufman ion source and an electron beam vapor source. The nitrogen-ion silicon-vapor material system is used for the calibration; Rutherford backscattering is used for measurement of composition and thickness of Si 1 x N vfilms deposited on C and Si substrates. It is shown that quantitative predictions of the ion-to-atom impingement ratio, film composition, and film thickness can be obtained when sputtering, reflection, charge exchange neutralization of the ions, and species content of the nitrogen beam are considered. © 1990, American Vacuum Society. All rights reserved.