Atomic Defects Profiling and Reliability of Amorphous Al2O3 Metal–Insulator–Metal Stacks

We present a comprehensive characterization of amorphous alumina (a-Al₂O₃) high- ${k}$ dielectric in metal–insulator–metal (MIM) stacks, self-consistently extracting the space-energy distribution of a-Al₂O₃ atomic defects and the related bond-breaking process parameters. Active defects are profiled via simultaneous simulation of current–voltage ( ${I}$ – $\textit {V}$ ), capacitance–voltage (CV), conductance–voltage (GV) (i.e., defect spectroscopy), and low-field ${I}$ – ${V}$ hysteresis analysis. The defect energies extracted ( ${E}_{TH}= 1.55$ and 3.55 eV) are consistent with oxygen vacancies and aluminum interstitials. The voltage-dependent dielectric breakdown (VDDB) statistics of a-Al₂O₃ is investigated using ramped voltage stress (RVS). The VDDB statistics show a complex and polarity-dependent breakdown statistics, correlating with defect distributions, which allows estimating the a-Al₂O₃ bond-breaking parameters with the support of multiscale atomistic simulations of the breakdown process.