Novel Approach for the Reduction of Leakage Current Characteristics of 20 nm DRAM Capacitors With ZrO2–Based High-k Dielectrics

In order to produce a dynamic random access memory (DRAM) of 20 nm or less, the most important concern regarding development is to reduce the leakage current degradation of the capacitor using high-k dielectrics. We studied the effect of defect sources present after the formation of the capacitor and measured the leakage current characteristics of the capacitor using the dielectric breakdown degradation test, a test used in mass production. From these results, we confirmed that the leakage current degradation was completely eliminated by removing external impurities of boron and hydrogen without any change in the structure or materials of the capacitor. For further DRAM scaling, we propose a method of reducing leakage current degradation of the capacitor.