质子辐照作用下浮栅单元的数据翻转及错误退火

Data inversion and erroneous annealing of floating gate cell under proton radiation

本文利用60 MeV质子束流,开展了NAND(not and)flash存储器的质子辐照实验,获取了浮栅单元的单粒子翻转截面,分析了浮栅单元错误的退火规律,研究了质子辐照对浮栅单元的数据保存能力的影响.实验结果表明,浮栅单元单粒子翻转截面随质子能量的升高而增大,随质子注量的升高而减小.浮栅单元错误随着退火时间的推移持续增多,该效应在低能量质子入射时更为明显.经质子辐照后,浮栅单元的数据保存能力有明显的退化.分析认为高能质子通过与靶原子的核反应,间接电离导致浮栅单元发生单粒子翻转,翻转截面与质子注量的相关性是因为浮栅单元单粒子敏感性的差异.质子引起的非电离损伤会在隧穿氧化层形成部分永久性的缺陷损伤,产生可以泄漏浮栅电子的多辅助陷阱导电通道,导致浮栅单元错误增多及数据保存能力退化.

In this paper,the 60-MeV proton beam is used to carry out the proton irradiation experiment on NAND(not and)flash memory,the single-event-upset cross section data of the floating gate cell are obtained,the annealing rule of the floating gate cell errors is analyzed,and the effect of proton irradiation on the data retention capability of floating gate cells is studied.The obtained results are as follows.The single-event-upset cross section of the floating gate cell increases with the increase of proton energy,and decreases with the increase of proton fluence.The floating gate cell errors continue to increase over time,and this effect is more pronounced when low energy protons are incident.After proton irradiation,the data retention capability of the floating gate cell is significantly degraded.The analysis suggests that the high energy protons are indirectly ionized through the nuclear reaction with the target atom,causing single-event-upset of the floating gate cell.The correlation between the upset cross section and the proton fluence is due to the difference in single-event-effect sensitivity of the floating gate cell.The proton-induced non-ionizing damage can form partially permanent defect damage in the tunnel oxide layer,creating multiple auxiliary trap channels that can leak floating gate electrons,resulting in the increase of floating gate cell errors and the degradation of data retention capability.