Enhancement in Thermal Stability of Metal-Insulator-Metal Capacitors for Deep Trench DRAM Application

The high-temperature thermal stability of a metal-insulator-metal (MIM) capacitor has been disclosed and improved by embedding a WN barrier layer between bottom electrodes and high-k dielectrics. The interfacial reaction between high-k dielectrics and bottom electrode during high temperature annealing was suppressed. Therefore, both equivalent oxide thickness (EOT) and leakage current were well controlled to meet the criterion of deep trench DRAM technology beyond 50nm.