Pre- and post-breakdown electrical studies in ultrathin Al2O3 films by conductive atomic force microscopy

The loss of local dielectric integrity in ultrathin Al2O3 films grown by atomic layer deposition is investigated using conducting atomic force microscopy. I–V spectra acquired at different regions of the samples by constant and ramping voltage stress are analyzed for their pre- and post-breakdown signatures. Based on these observations, the thickness dependent dielectric reliability and failure mechanism are discussed. Our results show that remarkable enhancement in breakdown electric field as high as 130 MV/cm is observed for ultrathin films of thickness less than 1 nm. •The local dielectric breakdown phenomena in ultrathin Al2O3 films are investigated.•Pre- and post-breakdown signatures are evaluated by statistical analysis of IV spectra.•The thickness dependent dielectric reliability and failure mechanism is reported.•The dielectric breakdown field as high as 130 MV/cm is observed for ultrathin films.