Growth of ultrathin SiO2 on Si by surface irradiation with an O2+Ar electron cyclotron resonance microwave plasma at low temperatures

Abstract

Ultrathin ${\mathrm{SiO}}_{\mathrm{2}}$ films were grown by Si surface irradiation with an ${\mathrm{O}}_{\mathrm{2}}\mathrm{+Ar}$ electron cyclotron resonance (ECR) microwave plasma at low temperatures. These films without hydrogen and silicon deposition were easily grown in a few minutes at low temperatures and at relatively low working pressures ${\text{(1.0–3.9×10}}^{\text{−1}}$ Pa). The promoting growth process of an ultrathin oxidized layer (1–9 nm) was analyzed by in situ Fourier transform infrared reflective absorption spectroscopy. By using the sputter erosion technique, the dependence of x-ray photoelectron spectroscopy on the depth profiling of the films was obtained. The compositional deviations of the films from the stoichiometric ${\mathrm{SiO}}_{\mathrm{2}}$ were also discussed in the interface region of ${\mathrm{Si/SiO}}_{\mathrm{2}}.$ This study indicated that an ${\mathrm{O}}_{\mathrm{2}}$ ECR microwave plasma was efficient to form controlled ultrathin ${\mathrm{SiO}}_{\mathrm{2}}$ dielectric films. The dependence of the film quality on the working pressure and gas flow rate ratios of the ${\mathrm{O}}_{\mathrm{2}}$ to Ar was discussed.