Intense ultraviolet photoluminescence centered at 370 nm was observed from magnetron-sputtered silicon oxide films after they were annealed at about 1000 °C inN2atmosphere. This photoluminescence is found to be associated with the formation of nanocrystal silicon particles in the specially structuredSiO2,which highly resembles the oxide layer of porous silicon. The luminescence centers at the interface between the nanocrystal silicon particles and theSiO2matrix are responsible for the strong ultraviolet luminescence. ©1998 American Institute of Physics.