First-Principles Studies of the Electronic and Dielectric Properties of Si/SiO2/HfO2 Interfaces

Abstract

In an effort to link first-principles electronic structure information with device-level modeling and simulations, first-principles calculations were performed to model Si/SiO2/HfO2 gate stacks, and models of their interfaces were developed. The electronic and dielectric properties, including the band edge and the local dielectric constant profiles, were investigated and found to display non-abrupt transitions at the hetero-material boundaries. The first-principles equivalent oxide thickness (EOT) parameter was introduced to represent the overall dielectric characteristics of the gate stack. The role of defects in the oxides was investigated by performing first-principles calculations of a Si/SiO2/HfO2 slab model with an oxygen vacancy near the SiO2/HfO2 interface. The oxygen vacancy was found to reduce the EOT. (C) 2013 The Japan Society of Applied Physics