| dc.description.abstract | As Moore’s Law scaling has pushed the limits of transistor fabrication to sub-10 nm, researchers and engineers have broadened approaches for achieving increased performance in semiconductor devices to include vertical and heterogeneous integration with novel transistor structures. 3D NAND flash memories are currently one of the best examples of highly scaled vertically integrated circuits on the market, offering increased memory densities in significantly reduced package footprints which make them ideal candidates for use in space missions among other applications. Understanding and characterizing the manifestations of radiation-induced failure in 3D NAND is therefore important, and differences in architecture and layout between manufacturers may lead to significant variability in device response and radiation hardness. This research presents a mechanistic analysis and comparison of structure-dependent effects for charge-trap and floating-gate 3D NAND, including total dose and single-event effects, using the Monte Carlo Radiative Energy Deposition (MRED) tool. Simulation details are validated against experimental data, and are used to provide insight into the depth-dependent upset profile observed with direct ionization from low energy protons. Other key findings show that the presence of high-Z metals such as tungsten in charge-trap 3D NAND results in a dose-enhancement effect throughout the memory array in X-ray and gamma environments, as well as an increase in the single-event upset (SEU) cross section in heavy-ion environments. Trade-offs between SEU hardness and memory density are characterized for different cell operating modes, and SEU profiles in multi-die packages are introduced with implications for experimental testing and part qualification. | |
