Stacked SiO2/Si3N4/SiO2dielectric layer for reliable memory capacitor

This papar deals with the reliability aspects of the stacked film of SiO2/Si3N4/SiO2as a dielectric layer for dynamic memories. The leakage current of the MIS capacitor with the stacked film is sufficiently small. It is well explained by a model with Fowler-Nordheim (F-N) current in SiO2and Poole-Frenkel (P-F) current in Si3N4. Using this model, the flat band voltage shifts of the MIS capacitor are estimated to be less than IV under the operating voltage 5V. Compared with MOS capacitors, the stacked MIS capacitors show a lower failure rate of time-zero dielectric breakdown, a smaller electric field acceleration factor, and a comparable activation energy of time dependent dielectric breakdown (TDDB). The stacked layer is prominent as a dielectric layer for dynamic memories with small geometry.