ION-BOMBARDMENT OF SIO2 SI AND SI MEASURED BY IN-SITU X-RAY REFLECTIVITY/

We have used in situ energy dispersive X-ray reflectivity to measure t he evolution of struCture and morphology during ion bombardment of thi n films of SiO2 on Si and of clean Si. The high resolution of this tec hnique (0.3 nm in film thickness and 0.04 nm in surface roughness) mak es it possible to resolve thin film structures that are difficult to d etect by other means, while the reasonably short acquisition time ( < 1000 s per spectrum) makes it possible to study the kinetics of layer modification. We present measurements of low-energy (600-1000 eV) ion bombardment which demonstrate the ability of the technique to resolve very shallow ( < 4 nm) implanted regions. We also compare the kinetics of surface roughening by reactive H ions and inert Xe ions on an amor phous oxide (SiO2) With that on a crystalline semiconductor (Si, Ge). H ions were observed to smoothen SiO2 surfaces that were made rough by prior Xe ion bombardment. Details of the energy dispersive technique and its benefits for in situ measurements are described.