Dependence of ultra-thin SiO2 layers formation by ultra-slow single and multicharged ions on process conditions

Ultra-slow single and multicharged ions (USMCIs) can be used for surface pr eparation at room temperature, to engineer the top atomic layers of surface s without modifying the substrate below, in processes such as ultra-thin fi lms growth, etching, deposition, or nanostructures fabrication. The energy for the reaction is brought to the surface through the USMCI potential ener gy, which can be controlled by varying the ions charges. The USMCI kinetic energy is so small that they do not penetrate below the surface. We have us ed various USMCIs under low pressures of O-2 (up to 5 (.) 10(-6) Torr) to g row ultra-thin films of SiO2 on Si wafers, up to 1.5 nm with a resolution o f +/-0.1 nm and a uniformity of +/-0.1 rum. To optimize this process, we ha ve analyzed the surfaces by Fourier transform infrared spectroscopy, auger electron spectroscopy, spectroscopic ellipsometry and transmission electron microscopy. (C) 2001 Elsevier Science B.V. All rights reserved.