In order to improve the discharge characteristics of MgO protective layer, SiO2 was added to MgO thin films. The MgO-SiO2 thin films were deposited by electron beam evaporation method. The crystallinity and surface roughness of thin films were determined by XRD and AFM. Discharge characteristics of MgO-SiO2 protective layers were observed by changes in discharging voltages and SEE and memory coefficients as a function of Si concentration in the protective layer. The discharge characteristics of MgO-SiO2 layer were mainly affected by changes in crystallinity and surface roughness of films with Si concentration in the range of present study. With addition of 12.5 Si at.% in MgO-SiO2 protective layer, the discharge voltages and memory and SEE coefficients were considerably improved in comparison to pure MgO protective layer. (c) 2006 Elsevier B.V. All rights reserved.