The charge trapping characteristics of Si 3N 4 and Al 2O 3 layers on amorphous-indium-gallium-zinc oxide thin films for memory application

Abstract

The charge trapping characteristics of 30-nm-thick Si 3N 4 and 3-nm-thick Al 2O 3 layers between amorphous In-Ga-Zn-O thin films and 100-nm-thick blocking oxides made of thermal SiO 2 were examined. The Si 3N 4 layer showed several discrete trap levels with relatively low density, while the Al 2O 3 layer showed a higher trap density with continuous distribution for electron trapping. When no tunneling oxide was adopted, the trapped carriers were easily detrapped, even at room temperature. Adoption of a 6-nm-thick SiO 2 tunneling layer grown by atomic layer deposition largely improved the retention of the trapped charges and retained ∼60 of the trapped charges even after 10 000 s. © 2012 American Institute of Physics.