New TIT Capacitor with ZrO2/Al2O3/ZrO2 dielectrics for 60nm and below DRAMs

New ZrO2/Al2O3/ZrO2 (ZAZ) dielectric film was successfully developed for DRAM capacitor dielectrics of 60nm and below technologies. ZAZ dielectric film grown by ALD has a mixture structure of crystalline phase ZrO2 and amorphous phase Al2O3 in order to optimize dielectric properties. ZAZ TIT capacitor showed small Tox.eq of 8.5 Aring and low leakage current density of 0.35fA/cell, which meet leakage current criteria of 0.5fA/cell for mass production. ZAZ TIT capacitor showed smaller cap leak fail bit than HAH capacitor and stable leakage current up to 550degC anneal. TDDB (time dependent dielectric breakdown) behavior reliably satisfied the 10-year lifetime criteria within operation voltage range