Title :
The degradation of TDDB characteristics of Si02/Si3 N4/Si02 stacked films caused by surface roughness of Si3N4 films [DRAMs]
Author :
Tanaka, Hiroyuki ; Uchida, Hidetsugu ; Ajioka, Tsuneo ; Hirashita, Norio
Author_Institution :
Oki Electr. Ind. Co. Ltd., Tokyo, Japan
fDate :
12/1/1993 12:00:00 AM
Abstract :
The effect of surface roughness of Si3N4 films on time-dependent dielectric breakdown (TDDB) characteristics of SiO2/Si3N4/SiO2 (ONO) stacked films was investigated. The surface roughness of Si3N 4 films-was found to become higher with increasing deposition temperature and to cause the degradation of TDDB characteristics of ONO films in DRAMs. A local thinning of ONO films, evaluated from the TDDB characteristics, agreed with the surface roughness measured by atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM). Dependence of time to breakdown of ONO films on the deposition conditions was interpreted by electric field intensification due to the surface roughness of Si3N4 films
Keywords :
DRAM chips; atomic force microscopy; electric breakdown of solids; insulating thin films; silicon compounds; surface topography; transmission electron microscope examination of materials; AFM; DRAMs; ONO films; Si02/Si3N4/Si02 stacked films; SiO2-Si3N4-SiO2; TDDB characteristics; XTEM; atomic force microscopy; cross-sectional transmission electron microscopy; deposition conditions; deposition temperature; electric field intensification; local thinning; surface roughness; time-dependent dielectric breakdown; Atomic force microscopy; Atomic measurements; Degradation; Dielectric breakdown; Force measurement; Rough surfaces; Semiconductor films; Surface roughness; Temperature; Transmission electron microscopy;
Journal_Title :
Electron Devices, IEEE Transactions on
