X-RAY REFLECTION, A TECHNIQUE FOR MEASURING SPUTTERING YIELDS OF THIN-FILMS

We used interference of;reflected soft X-rays to measure the thickness of thin films in real time during ion beam sputtering. We have applie d this technique to determine the sputtering yields of molybdenum, sil icon and nickel thin films for argon and krypton ions in an energy ran ge from 150 to 1500 eV. Sputtering yields ranging from 0.3 to 6.4 subs trate atoms per incoming energetic particle have been observed. Our ex periments also confirmed enhanced sputtering of silicon due to intermi xing with molybdenum as predicted from T-DYN calculations. From change s in the intensity of reflected radiation it is also possible to deriv e changes in the surface roughness and intermixing of the thin film wi th the substrate at the interface during sputtering.