Development of New TiN/ZrO2/Al2O3/ZrO2/TiN Capacitors Extendable to 45nm Generation DRAMs Replacing HfO2 Based Dielectrics

New ZrO ₂ /Al ₂ O ₃ /ZrO ₂ (ZAZ) dielectric film was theoretically designed and successfully demonstrated to be applicable to 45nm DRAM devices. ZAZ dielectric film is a combined structure from tetragonal ZrO ₂ and amorphous Al ₂ O ₃ . Thus prepared ZAZ TFT capacitors showed very small Tox.eq value of 6.3Å and low leakage current less than 1fA/cell. It was also confirmed that ZAZ TFT capacitor was thermally robust during backend full thermal process by applying it to the final DRAM product in mass production