Experimental investigations on ferroelectric dielectric breakdown in sub-10 nm Hf_0.5Zr_0.5O₂ film through comprehensive TDDB characterizations

Abstract

A deep insight is aimed at into the degradation of ferroelectric thin film and, systematical time-dependent dielectric breakdown characterizations in sub-10 nm Hf0.5Zr0.5O2 (HZO) film are performed and analyzed in this work. First, it is found that the anti-ferroelectric t-phase becomes more competitive when the film thickness decreases, and the wake-up effect is related to the phase transition. Second, the experimental phenomenon proves the correlation between soft breakdown and hard breakdown in the thin film, especially at low voltages. Furthermore, it is evident that a larger hard breakdown Weibull slope presents in thinner HZO film, showing the opposite trend to conventional dielectrics such as SiO2. The underlying mechanisms are discussed, and it is concluded that the t-phase interface layer, as well as the pre-existing defects in bulk film, are important factors for thin HZO-based devices.

Effect of electrical stress on time dependent dielectric breakdown (TDDB) tolerate capability of HfO2–ZrO2 ferroelectric films with different thicknesses

“…Apart from the aforementioned non-ideal effects that affect the performance of HfO 2 -based FE films, it is crucial to carefully consider the leakage current issues and the loss of FE properties caused by time dependent dielectric breakdown (TDDB) in practical applications [18][19][20]. Previous studies by Liu et al suggested that the presence of significant pre-existing oxygen vacancies near the bottom electrode can lead to limited TDDB, and improving the stability of TDDB in HfO 2 -ZrO 2 (HZO) FE films can be achieved by reducing defects near the bottom electrode [21].…”