A METHOD FOR FABRICATION OF A HIGH CAPACITANCE INTERPOLY DIELECTRIC

摘要

A method for fabricating a silicon dioxide/silicon nitride/silicon dioxide (ONO) stacked composite (40) having a thin silicon nitride layer (16) for providing a high capacitance interpoly dielectric structure (70). In the formation of the ONO composite, a bottom silicon dioxide (14) layer is formed on a substrate such as polysilicon (52). A silicon nitride layer (16) is formed on the silicon dioxide layer and is thinned by oxidation. The oxidation of the silicon nitride film (16) consumes some of the silicon nitride by a reaction that produces a silicon dioxide layer (18). This silicon dioxide layer (18) is removed with a hydrofluoric acid dilution. The silicon nitride layer (16) is again thinned by re-oxidation as a top silicon dioxide layer (20) is formed on the silicon nitride layer (16) forming the ONO stacked composite (40). A second layer of polysilicon (54) is deposited over the ONO stacked composite (40), forming an interpoly dielectric (70).