Comparative Study of Quick Electron Detrapping and Random Telegraph Signal and Their Dependences on Random Discrete Dopant in Sub-40-nm NAND Flash Memory

In sub-40-nm flash memory, random discrete dopant (RDD) effect modulates post program/erase (P/E) cycling V t instabilities through quick electron detrapping (QED) as well as random telegraph signal (RTS). In this letter, for the first time, we discuss the QED phenomenon and its physical origin by comparison with RTS phenomenon. P/E cycling stress not only aggravates the RTS but also generates the new phenomenon of QED which results from transiently trapped charges at near-interface defects during program. By applying a new test algorithm, we could successfully extract the QED component from RTS, both of which are modulated by RDD effect and worsen tail bits in multilevel-cell flash memory.