Pre- and post-BD electrical conduction of stressed HfO_2/SiO_2 MOS gate stacks observed at the nanoscale

摘要

In this work, the electrical properties of fresh and stressed HfO_2/SiO_2 gate stacks have been studied using a prototype of Conductive Atomic Force Microscope with enhanced electrical performance (ECAFM). The nanometer resolution of the technique and the extended current dynamic range of the ECAFM has allowed to separately investigate the effect of the electrical stress on the SiO_2 and the HfO_2 layer of the high-k gate stack. In particular, we have investigated this effect on both layers when the structures where subjected to low and high field stresses.