Atomic layer growth of SiO ₂ on Si(100) using the sequential deposition of SiCl ₄ and H ₂ O

This study explored the surface chemistry and the promise of the binary reaction scheme: (A) Si-OH + SiCl ₄ → Si-Cl + HCl (B) Si-Cl + H ₂ O → Si-OH + HCl for controlled SiO ₂ film deposition. In this binary ABAB... sequence, each surface reaction may be self-terminating and ABAB... repetitive cycles may produce layer-by-layer controlled deposition. Using this approach, the growth of SiO ₂ thin films on Si(100) with atomic layer control was achieved at 600 K with pressures in the 1 to 50 Torr range. The experiments were performed in a small high pressure cell situated in a UHV chamber. This design couples CVD conditions for film growth with a UHV environment for surface analysis using laser-induced thermal desorption (LITD), temperature-programmed desorption (TPD) and Auger electron spectroscopy (AES). The controlled layer-by-layer deposition of SiO ₂ on Si(100) was demonstrated and optimized using these techniques. A stoichiometric and chlorine-free SiO ₂ film was also produced as revealed by TPD and AES analysis. SiO ₂ growth rates of approximately 1 ML of oxygen per AB cycle were obtained at 600 K. These studies demonstrate the methodology of using the combined UHV/high pressure experimental apparatus for optimizing a binary reaction CVD process.