In this work, an experimental study on the atmospheric neutron single-event effects in 128-layer charge trapping (CT) 3D NAND flash memory is conducted by using the atmospheric neutron irradiation spectrometer (ANIS) at the China Spallation Neutron Source (CSNS). By integrating irradiation experiments, reverse analysis, and Monte Carlo neutron transport simulations, the influence of atmospheric neutron irradiation on the multiple-cell upset (MCU) susceptibility of CT 3D NAND flash memory is investigated and the underlying mechanisms, including the distribution of secondary particles within the sensitive volume and the characteristics of deposited charge are analyzed.

The results indicate that under broad-spectrum neutron irradiation, the primary failure modes in CT 3D NAND flash memory are single-bit upsets (SBU) and MCU, with SBU accounting for 82.55% of the total events. By constructing a three-dimensional spatial distribution map of single-event upset (SEU), it is observed that compared with the dense “string-like” distribution formed by ⁷⁸Kr ion irradiation (LET = 11.4 MeV·cm²·mg^–1), the spatial distribution resulting from neutron-induced SEU is much more random, with the former having only a small number of MCU showing a “string-like” pattern. Among the MCU events, 2-bit MCUs are dominant, accounting for 83.6% of all MCUs, while larger sized MCUs (>2 bits) makes up 16.4%. The maximum observed MCU size is 7 bits. Furthermore, the spatial distribution of MCUs is primarily aligned along the direction of neutron incidence.

By using the reverse analysis results, a device model is constructed, and Monte Carlo neutron transport simulations are performed. The simulation results reveal that secondary particles generated in the sensitive volume (SV) of the device by neutrons with energy E > 1 MeV are predominantly silicon ions (37.98%) and nitrogen ions (27.95%). Since the SV material is nitride, the interaction between neutrons and the SV is mainly elastic scattering, during which secondary particles are produced. Among the secondary particles generated in the SV, most propagate along the direction of neutron incidence, while a small number of secondary particles in the central region produce oblique tracks. The majority of secondary particles generated in the SV have low LET values (<5 MeV·cm²·mg^–1) and short ranges (<100 nm), and these secondary particles are the primary cause of SBU. However, approximately 1.2% of the ions exhibit high linear energy transfer (LET) values (>10 MeV·cm²·mg^–1), with the maximum LET value of secondary particles in the SV reaching 12.05 MeV·cm²·mg^–1. A small number of secondary particles with high LET values and long ranges are responsible for generating MCUs.