Application of secondary neutral mass spectrometry in low-energy sputtering yield measurements

An experimental study was initiated to measure low-energy (150 to 600 eV) sputtering yields of molybdenum with xenon ions using a Secondary Neutral Mass Spectrometer (SNMS). An ion gun was used to generate the ion beam. The ion current density at the target surface was approximately 30 mu A/cm(2). The SNMS spectra obtained at 50 degrees incident angle were converted to sputtering yields for perpendicular incidence by normalizing SNMS spectral data at 500 eV with the yield measured by Rutherford backscattering spectrometry. Sputtering yields as well as the shape of the yield-energy curve obtained in this manner are in reasonable agreement with those measured by other researchers using different techniques. Sputtering yields calculated by using two semi-empirical formulations agree reasonably well with the measured data.