Oxide-Nitride Storage Dielectric Formation in a Single-Furnace Process for Trench DRAM

A simplified and integrated technique has been proposed to form an oxide/nitride storage dielectric in a single-furnace process by low-pressure oxidation and nitride film deposition with an extra N₂ O treatment for the trench dynamic random access memory (DRAM). Compared to the conventional nitride/oxide dielectric, this newly developed dielectric enjoys cell-capacitance-enhancement factor as high as 12.5% without degrading the leakage current and electron-trapping property. From the reliability test, the qualification for the DRAM application is also proven by the dielectric lifetime longer than 10-years. Most importantly, this technique can reduce the production cycle time without an additional equipment investment, which is essential in the cost-competitive DRAM arena