Atomic-level study of TDDB mechanism of Hf-doped SiON gate dielectrics using Cs-corrected STEM and atom probe tomography

A detailed structural analysis of Hf-doped SiON dielectrics was performed by using advanced physical analysis techniques: Cs-corrected scanning transmission electron microscopy (STEM) and three-dimensional (3-D) atom-probe (AP) tomography. We confirmed that the distribution and agglomeration of Hf atoms cause a time dependent dielectric breakdown (TDDB) in Hf-doped SiON dielectrics gate stacks. We revealed that the behavior of Hf atoms in dielectrics is related to the TDDB lifetime, which depends on Hf concentration and the polarity of electrodes. The TDDB mechanism of Hf-doped SiON dielectrics was successfully revealed in detail, based on physical analysis results.