Interfacial and electrical properties of Al2O3/HfO2 bilayer deposited by atomic layer deposition on GeON passivated germanium surface

The interfacial and electrical properties of HfO2 (5 nm) and Al2O3 (3 nm)/HfO2 (5 nm) high-k deposited on nitride passivated Ge (100) have been investigated. The XPS spectroscopy and HRTEM were used to study the chemical and interfacial properties of deposited thin films. The stack with only HfO2 shows the suppressed electrical properties such as high value of EOT and density of interface traps. The C-V measurement shows the reduced frequency dispersion with small hysteresis after introduction of 3 nm Al2O3 between HfO2 and Ge/GeON. Further, low EOT and D-it have been obtained for GeON/Al2O3/HfO2 gate stack as compared to that of only HfO2 stack. The obtained values of dielectric constant and leakage current density are of similar to 24.18 and 1.6 x 10(-6) A cm(-2) at 1 V gate bias, respectively for the stack with Al2O3. Overall, the 3 nm Al2O3 capping with GeON improves interfacial and electrical properties of Ge MOS devices. (C) 2016 Elsevier Ltd. All rights reserved.