Ultrathin HfO2(EOT < 0.75 nm) gate stack with TaN/HfN electrodes fabricated using a high-temperature process

Abstract

High quality TaN/HfN/HfO2 gate stacks with 0.65 nm of the equivalent oxide thickness and 0.3 A/cm2 at (-1V + VFB) of the gate leakage have been demonstrated. An NH3-based Si-surface nitridation process was performed prior to HfO2 deposition. The HfO2 films were deposited in a metallorganic chemical vapor deposition cluster tool. The TaN/HfN metal stacked layers were deposited on HfO2 by reactive sputtering. The gate stack shows excellent thermal stability, in equivalent oxide thickness (EOT) and leakage after 1000°C annealing. A 10-year time dependent dielectric breakdown lifetime of 1000°C rapid thermal anneal annealed HfN/HfO2 stack is projected at V g = -3 V with an EOT = 0.75 nm. © 2005 The Electrochemical Society. All rights reserved.