FORMATION OF HIGH-QUALITY STORAGE CAPACITOR DIELECTRICS BY IN-SITU RAPID THERMAL REOXIDATION OF SI3N4 FILMS IN N2O AMBIENT

Abstract

This letter reports on a novel reoxidation technique for SiO2/Si3N4 (ON) stacked films by using N2O as oxidant. Effect of in-situ rapid thermal N2O reoxidation (RTNO) on the electrical characteristics of thin ON stacked films are studied and compared with those of in-situ rapid thermal O2 reoxidation (RTO). Prior to reoxidation, the Si3N4 film was deposited by rapid thermal chemical vapor deposition (RT-CVD) using SiH4 and NH3. Results show that RTNO of the Si3N4 films significantly improves electrical characteristics of ON stacked films in terms of lower leakage current, suppressed charge trapping, reduced defect density and improved time-dependent-dielectric-breakdown (TDDB), as compared to RTO of the Si3N4 films.