ABSTRACT: The charge-trapping properties of the high-permittivity titanium oxide–hafnium silicate–silicon dioxide ( Ti O <sub>2</sub>/ Hf Si O / Si O <sub>2</sub>) gate stacks have been studied using scanning capacitance microscopy. From the bias stress examination of the gate stacks, we concluded that there were electron traps within the films, and these trap densities increased with an increase in the oxidation temperature used for the fabrication of Ti O <sub>2</sub> top dielectrics. Furthermore, we found that the distribution of these charged defects was inhomogeneous within the gate stacks. These results are attributed to Ti diffusion through the dielectric layers, which caused electrical defects within the gate stacks.
Applied Physics Letters 02/2008; · 3.84 Impact Factor