DIELECTRIC FILM FOR DYNAMIC-RANDOM-ACCESS-MEMORY-CELL AND FORMING METHOD THEREOF

摘要

PURPOSE: To provide an extremely thin triple layer dielectric film to be used for a storage capacitor in a dynamic random access memory(DRAM) cell. CONSTITUTION: The equivalent thickness of a dielectric film 10 is about 7nm thick and below. In the case of preparing a capacitor film, a silicon dioxide thin film on a substrate is nitrogenized or a silicon substrate or silicon stuck to a substrate is directly nitrogenized to form a silicon oxynitridated silicon layer 11. A thin silicon nitride layer 12 is stuck to the surface of the layer 11, the upper part of the layer 12 is oxidized at a high temperature for a short time to convert the upper part of the layer 12 into a thin silicon dioxide layer 13. The obtained structure is an oxynitridated silicon/silicon nitride/silicon dioxide dielectric film having 7nm thick and below of equivalent thickness with high capacitance.