Self-assembly of Al2O3 nanodots on SiO2 using two-step controlled annealing technique for long retention nonvolatile memories

A self-assembly of high-density Al2O3 nanodots (NDs) on SiO2 has been demonstrated by employing a two-step controlled annealing method. Results show that the conglomeration of Al is impeded by oxygen and the size and density of Al2O3 NDs can be controlled by the initial Al film thickness and annealing temperature. Memory devices with Al2O3 NDs fabricated using this technique show improved retention properties compared to those with Al2O3 continuous films. A comparison of temperature dependency shows that the good retention property originates from the suppression of lateral migration of electrons via Frenkel–Poole tunneling.