Silicon oxy-nitride (SiOxNy) films prepared by radio-frequency magnetron Sputtering were investigated as an anode modifier in organic light-emitting diodes (OLEDs). SiOxNy films were deposited on the indium tin oxide (ITO) anode of an OLED with a configuration of ITO/SiOxNy/alpha-naphtylphenyliphenyl diamine (NPB)/8-hydroxyquinoline aluminum (AlQ)/Mg:Ag. By varying the argon and oxygen flow ratio during deposition of the SiOxNy films, devices with improved electroluminescent performance and operation lifetime were obtained. Atomic compositions of the SiOxNy films were analyzed with X-ray photoelectron spectroscopy. The best device with the optimized SiOxNy film showed a half brightness lifetime 5 times better than that of the control device. (C) 2008 Elsevier B.V. All rights reserved.