Abstract
The operating characteristics of flash memory devices with tunnel dielectrics comprising a hafnium oxynitride (HfO x N y ) layer or a hafnium oxynitride/silicon dioxide (HfO x N y /SiO 2 ) stack, annealed at various temperatures, were studied. The present work indicates that flash memory devices with a HfO x N y /SiO 2 stack tunnel dielectric have a higher program/erase speed and better reliability than those with a single HfO x N y layer. The stack tunnel dielectric composed of a thick HfO x N y layer and a thin SiO 2 layer exhibits an even better performance in the flash memory operation. In addition, devices with HfO x N y /SiO 2 stack tunnel dielectrics annealed at 850°C show the best performance in terms of the program/erase speed, charge retention, and read disturbance. © 2006 American Vacuum Society.