Random Telegraph Noise and Radiation Response of 80 nm Vertical Charge-Trapping NAND Flash Memory Devices With SiON Tunneling Oxide

Abstract

Random telegraph noise (RTN) measurements are performed on as-processed, programmed, erased, and irradiated 80 nm vertical charge-trapping nand memory transistors. Variations in current with time of up to ±20% are observed during the RTN testing interval. The RTN of these devices is relatively unaffected by irradiation of devices to 500 krad(SiO2). Root-mean-square (rms) magnitudes of measured RTN exceed predictions of number-fluctuation models (NFMs) by up to six-times. This result demonstrates that fluctuations in carrier scattering rates caused by motion and/or reconfiguration of traps at grain boundaries likely lead to a significant fraction of the low-frequency noise and/or RTN in poly-crystalline Si channel, charge-trapping memory devices. The magnitudes of these fluctuations may present significant challenges to the resolution of highly scaled 3-D memory devices.