Paper Info
Title
Investigation on X-ray irradiation on nanoscale nitride based charge trapping flash memory devices.
Abstract
Charge trapping flash memory devices are susceptible to charge loss mechanisms induced by high energy irradiation such as thermal neutrons, X-rays, and gamma ray. The loss of trapped charges due to charge loss mechanism has resulted in the degradation in data retention performance and unwanted read failures in field applications. In this work, charge loss mechanisms of nanoscale nitride based charge trapping flash memory devices due to irradiation of high energy X-rays were carefully studied and examined. Nitride based charge trapping flash memory device stored charges in the nitride storage layer of an Oxide-Nitride-Oxide stack. Threshold voltage of the nitride based charge trapping flash memory cells were collected before and after X-ray irradiation done onto the memory devices. Threshold voltage distributions have shown that significant number of cells at the lower end of the program distribution had perturbed from the overall distribution that was caused by X-ray irradiation induced charge loss mechanism. In this study, the effect of the use of 300μm Zn filter and its proximity to the device under study to mitigate the X-ray irradiation induced charge loss was also thoroughly elucidated. The results have demonstrated that 300μm Zn filter has significantly improved the immunity of nitride based charge trap flash memory device up to 6.446 times. However, the proximity of the Zn filter to the flash memory device exacerbated up to 7.4280 times due to the impact of secondary effect in X-ray fluorescence to the device under study. Hence, this investigation concluded that X-ray irradiation is a genuine reliability concern for nanoscale nitride based charge trapping flash memory devices. Furthermore, it is recommended to place Zn filter close to X-ray source to significantly mitigate the Vt distribution drift induced by X-ray irradiation.
Year
DOI
Venue
2017
10.1016/j.microrel.2017.10.015
Microelectronics Reliability
Keywords
Field
DocType
Charge trapping,Flash memory,X-ray irradiation,Charge loss,X-ray fluorescence
Flash memory,Electrostatic induction,Nitride,Irradiation,Neutron temperature,Electronic engineering,Trapping,Engineering,Threshold voltage,Optoelectronics,Charge trap flash
Journal
Volume
ISSN
Citations 
79
0026-2714
0
PageRank 
References 
Authors
0.34
1
2
Name
Order
Citations
PageRank
Meng Chuan Lee101.01
Hin Yong Wong202.03