Ultrathin insulating silica layers prepared from adsorbed TEOS, H2O and NH3 as a catalyst

Homogeneous ultrathin silica films were deposited without need of any expensive equipment and high-temperature processes (t?200 °C). Repeated adsorption of tetraethoxysilane (TEOS) multimolecular layers and their subsequent reaction with H₂O/NH₃ mixed vapours at atmospheric pressure and room temperature were used. By preparing the Al/SiO₂/N-Si MOS structure conditions were attained for electrical characterisation of the thin oxide layer by capacitance (C-V) and current (I-V) measurements. These measurements confirmed acceptable insulating properties of the oxide, the maximum breakdown field intensity being E_bd=5.4 MV/cm. The total defect charge of the MOS structure was positive, affected by a high trap density at the Si-SiO₂ interface.