Reliability nano-characterization of thin SiO2 and HfSixOy/SiO2 gate stacks

In this work, a conductive atomic force microscope (CAFM) has been used in order to detect and electrically characterize the evolution of dielectric degradation on thin (<5nm) SiO2 oxides and on SiO2/HfSixOy gate stacks on a nanometer scale. In SiO2 oxides we illustrate the evolution of the break down event, from the creation of individual leakage spots to their propagation to larger areas of high conductivity. We also report significant changes in apparent topography and current map after stress for both SiO2 and HfSixOy/SiO2 stacks. Post break down conduction for both dielectrics is modeled and discussed.