Title :
Heavy oxynitridation technology for forming highly reliable flash-type EEPROM tunnel oxide films
Author :
Fukuda, Hiroshi ; Uchiyama, Asami ; Kuramochi, T. ; Hayashi, Teruaki ; Iwabuchi, T.
Author_Institution :
Oki Electric Industry Co. Ltd., Tokyo, Japan
Abstract :
For the first time, it is demonstrated that in flash-type EEPROMs, the endurance properties are dramatically improved by heavy oxynitridation (RTONO) of the tunnel oxide. The layer composition evaluated by SIMS measurement indicates that large amounts of N atoms (>1020 atom/cm3) pile up at the SiO2-Si interface, and are distributed in the bulk SiO2. In addition, the RTONO film reduces the number of hydrogen atoms, which are the origin of electron traps. This oxynitridation causes a decrease of both electron and hole traps in the tunnel oxide, resulting in an improvement of the threshold voltage narrowing.
Keywords :
EPROM; circuit reliability; electron traps; hole traps; insulating thin films; integrated memory circuits; metal-insulator-semiconductor structures; nitridation; oxidation; secondary ion mass spectra; semiconductor-insulator boundaries; tunnelling; EEPROM; RTONO film; RTP; SIMS measurement; SiO 2-Si interface; SiO 2-Si 3N 4-SiO 2; electron traps; endurance properties; flash-type; hole traps; layer composition; memory devices; oxynitridation technology; rapid thermal ONO film; threshold voltage narrowing; tunnel oxide films;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:19921136
