D. Kropman, U. Abru, M. Strik, Estonian Maritime Academy, Tallinn, Estonia; Tondi Electronics, Tallinn, Estonia; Elcoteq, Tallinn, Estonia.

SiO₂ films, deposited upon silicon surface by cathodic reactive sputtering in oxygen atmosphere, have many advantage over those grown by thermal oxidation. Ease of control over oxide film properties through deposition condition is the most important of those advantages Positive charge predominate in the thermal oxide, while both positive and negative charge are possible in the sputtered oxide films. The charge behavior of SiO₂ films, prepared by cathodic reactive sputtering under various experimental condition, has been studied. A discontinuous change of the silicon surface potential occurs during the initial stage of film deposition. The surface potential is determined both by chemical pretreatment of the silicon wafer and by the sputtering conditions. A relation between the surface potential and the charge density in the oxide layer is indicative of the formation of charges during initial stages of the film deposition process. SiO₂ films with a small positive or negative effective residual charge can be produce in a reproducible manner by an appropriate choice of the silicon pretreatment (chemical and thermal) and sputtering conditions.