Electrical characteristics and conduction mechanisms of amorphous subnanometric Al2O3 –TiO2 laminate dielectrics deposited by atomic layer deposition

Electric conduction mechanisms ofamorphous Al2O3/TiO2 (ATO)-laminates deposited by atomic layer deposition with sub-nanometer individual layer thicknesses were studied in a large temperature range. Two characteristic field regions are identified. In the low field region (E ≤ 0.31 MV/cm), theleakage current is dominated by the trap-assistedtunneling through oxygenvacancies occurring in the TiO2, while in the highelectric field region (E > 0.31 MV/cm) the Poole Frenkel (PF) hopping is the appropriate conduction process with energy levels depending on the temperature and theelectric field. It is shown that the PF potential levels decrease with the applied ATO field due to the overlapping of the Coulomb potential.Amorphous ATO-laminates show the presence of two intrinsic potential energy levels ϕi, which are 0.18  eV for low temperature region and 0.4 eV at high temperature region. Oxygenvacancies are the main origin of traps, which is consistent with the principal mechanisms for leakage in ATO-laminates.

Source: Applied Physics Letters - November 14, 2016 Category: Physics Authors: Abdelkader Kahouli, Oleg Lebedev, Vu Hung Dao, Marwa Ben Elbahri, Wilfrid Prellier and Ulrike L üders Source Type: research