Nano-Thin Oxide Layers Formed on Hydrogen Plasma Modified Crystalline Si for Advanced Applications

Since the early days of silicon manufacturing, hydrogen gas treatment has been used to control the defect concentrations. Its beneficial effect can be enhanced using hydrogen plasma as a source of active atomic hydrogen. Hydrogen plasma modification of c-Si surface can be challenging because the plasma can induce precursors of defect centers that can persist at the interface and/or grown oxide after subsequent thermal oxidation. In the present study, we investigate nanoscale silicon dioxides with thicknesses in the range of 6–22 nm grown at low temperature (850 °C) in dry oxygen on radio frequency (RF) hydrogen plasma-treated silicon surface. The properties of these oxides are compared to oxides grown following standard Radio Corporation of America (RCA) Si technology. Electroreflectance measurements reveal better interface quality with enhanced electron mobility and lowered oxidation-induced stress levels when the oxides are grown on H-plasma modified c-Si substrates. These results are in good accordance with the reduced defect concentration established from the analysis of the current–voltage (<i>I</i>-<i>V</i>) and multifrequency capacitance–voltage (<i>C</i>-<i>V</i>) characteristics of metal-oxide-semiconductor (MOS) capacitors incorporating the Si-SiO₂ structures. The study proves the potential of hydrogen plasma treatment of Si prior to oxidation for various Si-based applications.