It is widely known that the presence of oxygen ambient during the deposition affects the properties of MgO films. However, there have not been sufficient studies done that take these effects into consideration. Therefore, in this study, we investigated the effects of O-2 ambient during the electron beam evaporation on the properties of both the MgO thin film as a whole and its surface. In terms of its effects on the films as a whole, the growth behavior and crystallographic orientations were considered. In terms of its effects on the surfaces of the films, the surface morphologies and surface electronic structures strongly related to the firing voltages of the panels were investigated. The column sizes of the film formed under O-2 ambient were larger than those of the film formed without O-2 ambient. The MgO film formed under O-2 ambient at a pressure of 2x10(-4) Torr had the highest (111) preferred crystallographic orientation. In addition, the surface of the film formed under 2x10(-4) Torr of O-2 ambient had the highest density of states of the valence band and the smallest bandgap. This caused the panel with the MgO film to have the lowest firing voltages. (c) 2007 The Electrochemical Society.