Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA.
Energy Sciences Institute, Yale West Campus, Yale University, West Haven, CT, 06516, USA.
Adv Mater. 2018 Mar;30(9). doi: 10.1002/adma.201705587. Epub 2018 Jan 12.
Understanding and possibly recovering from the failure mechanisms of phase change memories (PCMs) are critical to improving their cycle life. Extensive electrical testing and postfailure electron microscopy analysis have shown that stuck-set failure can be recovered. Here, self-healing of novel confined PCM devices is directly shown by controlling the electromigration of the phase change material at the nanoscale. In contrast to the current mushroom PCM, the confined PCM has a metallic surfactant layer, which enables effective Joule heating to control the phase change material even in the presence of a large void. In situ transmission electron microscope movies show that the voltage polarity controls the direction of electromigration of the phase change material, which can be used to fill nanoscale voids that form during programing. Surprisingly, a single voltage pulse can induce dramatic migration of antimony (Sb) due to high current density in the PCM device. Based on the finding, self-healing of a large void inside a confined PCM device with a metallic liner is demonstrated for the first time.
了解和可能恢复相变存储器 (PCM) 的失效机制对于提高其循环寿命至关重要。广泛的电气测试和故障后电子显微镜分析表明，粘连故障是可以恢复的。在这里，通过控制纳米尺度相变材料的电迁移，直接展示了新型受限 PCM 器件的自修复能力。与当前的蘑菇形 PCM 不同，受限 PCM 具有金属表面活性剂层，即使存在大的空洞，也能有效地焦耳加热来控制相变材料。原位透射电子显微镜电影显示，电压极性控制相变材料的电迁移方向，可用于填充编程过程中形成的纳米级空洞。令人惊讶的是，由于 PCM 器件中的高电流密度，单个电压脉冲即可引起 Sb 的剧烈迁移。基于这一发现，首次证明了具有金属衬里的受限 PCM 器件内部大空洞的自修复能力。
