INSITU ENERGY DISPERSIVE-X-RAY REFLECTIVITY MEASUREMENTS OF H ION-BOMBARDMENT ON SIO2/SI AND SI

We have performed in situ, energy-dispersive x-ray reflectivity measurements of damage layer formation and surface roughness of thin films of SiO2 on Si and clean Si during H ion bombardment. The reflectivity was analyzed using an optical multilayer model where the variable parameters are the number of layers, the thickness and density of the layers, and the surface roughness. Room temperature ion bombardment at doses < 5 X 10(17)/cm2 results in a buried layer between the oxide and the substrate; 300 eV bombardment produces a very thin, low-density layer, while 1000 eV bombardment produces a thicker layer with the density of amorphous silicon. A damaged layer is not produced by equivalent bombardment at high temperature. Ion bombardment of clean Si surfaces at 500-degrees-C resulted in roughening of the surface on the nanometer scale which is strongly dependent on the ion energy.