ENERGY AND FLUENCE DEPENDENCE OF THE SPUTTERING YIELD OF SILICON BOMBARDED WITH ARGON AND XENON

Using the quartz oscillator technique, we have measured the sputtering yield of silicon bombarded with 10-140-keV argon and 10-540-keV xenon, respectively. Considerable effort has been devoted to achieving high-purity silicon films with smooth surfaces and to calibrating the microbalance. In situ combination of the quartz oscillator technique with Rutherford backscattering allowed a quantitative determination of the fluence dependence of the sputtering yield. Measurements with xenon at 140 and 270 keV showed that the sputtering yield of silicon increases by about 25% due to loading of the target with projectile atoms. A simple estimate indicates that the yield enhancement is caused, to a large extent, by the increase in nuclear-energy deposition resulting from the accumulation of the heavy projectiles in silicon. The measured steady-state sputtering yields are in satisfactory agreement with results achieved by other experimental techniques. Discrepancies with results derived by other authors applying the quartz oscillator microbalance technique can be attributed to surface topography effects. Comparison of the measured energy dependence of the (steady-state) sputtering yield with theory shows good agreement.