Impact of Mechanical Stress on 3-D NAND Flash Current Conduction.

This work experimentally investigates current conduction in 3-D NAND under up to 7 GPa of externally applied compressive mechanical stress. The impact of channel crystallinity and geometry is studied by comparing four types of Si channels: polycrystalline full channel, single-crystal full channel, polycrystalline macaroni channel, and single-crystal macaroni channel. In the studied channel types, the mechanical stress was found to cause reversible degradation of ION (up to one order of magnitude) and IOFF (up to seven orders of magnitude). Using TCAD simulations, ION and IOFF deterioration are attributed to carrier mobility and Si bandgap decreases under mechanical stress, respectively. The simulations also suggest that both effects depend on the channel morphology, which results in a different extent of stress impact on the four studied types of Si channels. [ABSTRACT FROM AUTHOR]