特集：半導体プロセスの評価
走査型非線形誘電率顕微鏡によるフラッシュメモリ中の蓄積電荷の可視化
2007 年 28 巻 2 号 p. 78-83
詳細
2007 年 28 巻 2 号 p. 78-83
By applying Scanning Nonlinear Dielectric Microscopy (SNDM), we succeeded in clarifying the position of the electrons/holes in the gate SiO2-Si3N4-SiO2 (ONO) film of the Metal-ONO-Semiconductor type flash memories, After the write-erase cycling operation, the electrons were found in the Si3N4 part of the ONO film. The holes, on the other hand, were found in the Si3N4 film as well as at the bottom of the SiO2 film. This indicates that the electrons and holes are apparently neutralized but exist separately. We also succeeded in clarifying that electrons exist in the poly-Si layer of the floating gate of a flash memory. We confirmed that SNDM is one of the most useful methods for observing the charge in flash memories.
