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

Abstract

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 Ebd=5.4MV/cm. The total defect charge of the MOS structure was positive, affected by a high trap density at the Si–SiO2 interface.