连续性RESET/SET对相变存储器疲劳特性的影响

Impact of Continuous RESET/SET Operations on Endurance Characteristic of Phase Change Memory

为探究连续性RESET操作和连续性SET操作对相变存储器疲劳特性的影响,基于4 Mbit相变存储器芯片进行了不同RESET-SET次数比的疲劳特性研究,给出了连续RESET和连续SET操作后相变单元阻值分布的变化情况.将RESET-only与SET-only模式下的疲劳特性与常规疲劳特性进行了对比分析,并对失效原因和修复方法进行了讨论;对比了8种不同RESET-SET次数比下的单元疲劳特性.实验结果表明:连续性RESET操作对相变存储器疲劳特性的影响很小,RESET-only模式下的相变存储器疲劳特性与常规疲劳特性处于同一量级;连续性SET操作会显著降低相变存储器的的疲劳特性,SET-only模式下相变存储器疲劳特性比常规疲劳特性低2个数量级;连续性RESET操作带来的失效无法逆转,而连续性SET操作带来的失效可以通过间隙性施加RESET操作得以修复.

In order to explore the effects of continuous RESET operations and continuous SET operations on the endurance characteristic of phase change memory(PCM),the endurance characteristics of PCM at different ratios of RESET-SET times are studied based on a 4Mbit PCM chip.The variation of resistance distributions of PCM after continuous RESET and continuous SET operations are measured.The endurance characteristics of PCM in RESET-only and SET-only operations are compared with the typical endurance characteristic.Besides,the causes and repair methods of failure are also discussed.Moreover,the endurance characteristics of PCM at 8 different RESET-SET ratios are compared.The research results show that continuous RESET operation has little effect on the endurance characteristic of PCM,and the endurance characteristic of PCM in the RESET-only mode is on the same order as the typical endurance characteristic.However,the continuous SET operation has a significantly destructive effect on the endurance characteristic of PCM,and the endurance characteristic of PCM in the SET-only mode is 2 orders of magnitude lower than the typical endurance characteristic.The failure process of PCM caused by continuous RESET operation is irreversible while the failure process of PCM caused by continuous SET operation can be repaired by intermittent RESET operation.