Investigation on interface related charge trap and loss characteristics of high-k based trapping structures by electrostatic force microscopy

Charge trap and loss characteristics of high-k based trapping layer structures are investigated by electrostatic force microscopy, which proves that the interfaces provide dominate trap sites. The effects of post-deposition anneal of HfO2 and Al2O3 single layer are determined. Based on aforementioned findings, we demonstrate the HfO2/Al2O3 bi-layers trapping structure with improved performance. The lateral charge spreading properties are also evaluated by extracted diffusion coefficients to further understand the interface effect. The study may provide insights into fundamental assessment and optimization for charge trapping structures, especially for high-density NAND flash applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3664222]