Visualization Using the Scanning Nonlinear Dielectric Microscopy of Electrons and Holes Localized in the Thin Gate Film of Metal-Oxide-Nitride-Oxide-Semiconductor Type Flash Memory

Abstract

By applying scanning nonlinear dielectric microscopy (SNDM), we identified the position of electrons/holes existing in the gate SiO₂-Si₃N₄-SiO₂ (ONO) film of the Metal-Oxide-Nitride-Oxide-Semiconductor (MONOS) type flash memory. The electrons were detected in the Si₃N₄ part of the ONO film. The holes, on the other hand, were found in the Si₃N₄ film as well as in the bottom SiO₂ film. Additionally, we succeeded in detecting the electrons existed in the poly-Si layer of the floating gate of flash memory.