Visualization of Electrons Localized in Metal-Oxide-Nitride-Oxide-Semiconductor Flash Memory Thin Gate Films by Detecting High-Order Nonlinear Permittivity Using Scanning Nonlinear Dielectric Microscopy

摘要

Charge accumulation in semiconductor devices was investigated by using scanning nonlinear dielectric microscopy (SNDM) to detect a high-order nonlinear permittivity (ε_(3333)). This higher-order SNDM has a much higher resolution than conventional SNDM that is used to measure the lowest-order nonlinear permittivity (ε_(333)). It enabled us to visualize highly resolved charge patterns stored in SiO_2-SiN-SiO_2 (ONO) films of downsized metal-ONO-semiconductor (MONOS) flash memory with a high contrast. ε3333 images of the stored electron distributions in ONO films of n-MONOS exhibited the highest contrast reported by detecting ε_(333).