Modeling of Charge Failure Mechanisms during the Short Term Retention Depending on Program/Erase Cycle Counts in 3-D NAND Flash Memories
Changbeom Woo, Shin-Keun Kim, Jaeyeol Park, Hyungcheol Shin, Haesoo Kim, Gil-Bok Choi, Moon-Sik Seo, Keum Hwan Noh
Abstract
For the first time, we analyzed the effect of program/erase (P/E) cycles on short term retention in 3-D NAND flash memory. Trap-assisted tunneling (TAT) component with relatively large time-constant (τ) was found after P/E cycle stress. We have confirmed that the charge failure mechanisms consist of four components. Short term retention data measured at various temperatures and at several program verify levels (PV) for two patterns were analyzed and separated using our stretched exponential model. Finally, the activation energy (E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> ) of each charge failure mechanism was extracted by the Arrhenius law and the magnitudes of E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> were compared as a function of P/E cycle counts.