Hydrogen microwave plasma treatment of Si and SiO2

The impact of an argon/hydrogen microwave plasma treatment on silicon and silicon dioxide is investigated as a function of temperature as well as distance between plasma source and substrate. Both the silicon and silicon dioxide etching rates strongly decrease with increasing distance. The two etching rates do not show the same dependency due to the different influence of the plasma species on the two materials. We found that there exist two different regions where the influence of ions, electrons or radicals is mainly responsible for the etching performance of silicon and silicon dioxide. AFM measurements of the surface roughness substantiate this model. To verify the efficiency of the hydrogen plasma clean, MOS capacitors have been fabricated and samples were overgrown with thin epitaxial silicon layers.