Study of the silicon-silicon dioxide system as a junction between a nearly ideal semiconductor and insulator has aroused both scientific and technological interest. Surface phenomena associated with this system are influenced by contamination and imperfections in the oxide, impurity redistribution in the silicon near the oxide, and finally by additional electronic energy states at the oxide-silicon interface. Over the past few years, the MOS (metal-oxide-semiconductor) approach has been highly developed and is the principal tool for the investigation of silicon surface phenomena. The theory of the ideal MOS capacitor is reviewed followed by a study of its use in the analysis of surface effects. Finally, the three-way relationship of the effect of oxide formation conditions and heat treatment on the properties of the oxidized silicon surface, and the subsequent influence of the properties of this surface on semiconductor device parameters is reviewed.