A 100Å Thick Stacked SiO2/Si3N4/SiO2 Dielectric Layer for Memory Cafacitor

This paper deals with the reliability of the stacked film of SiO2/Si3N4/SiO2 with an oxide equivalent thickness ranging from 100A to 200A. The leakage current and the flat band voltage shift of the stacked film were found to be acceptable. A model based on Fowler-Nordheim current in the SiO2 and Poole-Frenkel current in the Si3N4 taking into account the trapped charges in the Si3N4 is presented. The stacked MIS capacitors show a lower failure rate of time-zero dielectric breakdown and time dependent dielectric breakdown (TDDB). Therefore, the stacked film is prominent as a thin dielectric layer of dynamic memories.