The Role of Carrier Injection in the Breakdown Mechanism of Amorphous Al2O3 Layers

We investigated the dielectric breakdown (BD) mechanism in amorphous alumina (a-Al2O3) metal-insulator-metal (MIM) stacks. Density functional theory (DFT) calculations reveal that oxygen vacancy ( $\text{V}_{\text {O}}{)}$ generation in a-Al2O3 occurs via thermochemical (TC) bond-breaking and, more efficiently, via newly discovered pathways enabled by charge trapping in under-coordinated Al ions (UC $_{\text {Al}}\text{s}$ ) and in existing $\text{V}_{\text {O}}\text{s}$ . Multiscale simulations show the importance of these processes, which allow explaining the experimental BD dynamics in a-Al2O3, and provide valuable insights into the role of carriers’ injection in the degradation and reliability of high-k materials.