近期，本课题组张敏老师和张娇娜同学以及王婉婷同学分别以通讯作者和共同第一作者在纳米科学和纳米技术研究领域国际知名期刊ACS Nano (Nature-index期刊，影响因子18.027)上发表题为“Ultraflexible Monolithic Three-Dimensional Static Random Access Memory”的文章，在这项工作中，基于单片三维（M3D）设计，成功实现了一种具有高集成密度的超柔性六晶体管SRAM。
柔性静态随机存取存储器（SRAM）在柔性电子系统中发挥着重要的作用。然而，实现面积小、柔性高、热稳定性高的SRAM一直是一个巨大的挑战。在这项工作中，基于单片三维（M3D）设计，实现了一种具有高集成密度的超柔性六晶体管SRAM。在该设计中，垂直堆叠的n型IGZO薄膜晶体管和p型碳纳米管晶体管分别共享公共的栅极和漏极，节省了在传统M3D设计中使用的层间过孔。这种紧凑的结构将SRAM单元从六个晶体管减少到了四个晶体管的面积，从而节省了33%的面积。并且在报道过的柔性SRAM工作中具有最高的柔性，其能够承受苛刻的变形过程（在500μm半径下弯曲6000次）而不会降低性能。此外，这种设计有利于SRAM在高温（333K）下的热稳定性。它还表现出良好的静态和动态性能，在所报道的柔性SRAM中，保持操作中的最高归一化保持噪声容限为73.6%，最大增益为151.2，最小静态功耗为3.15μW。该工作为SRAM在高级可穿戴系统应用中的使用提供了可能。
Flexible static random access memory (SRAM) plays an important role in flexible electronics and systems. However, achieving SRAM with a small footprint, high flexibility, and high thermal stability has always been a big challenge. In this work, an ultraflexible six-transistor SRAM with high integration density is realized based on a monolithic three-dimensional (M3D) design. In this design, vertical stacked n-type indium gallium zinc oxide thin film transistors and p-type carbon nanotube transistors share common gate and drain electrodes, respectively, saving interlayer vias used in traditional M3D designs. This compact architecture reduces the footprint of the SRAM cell from a six-transistor to a four-transistor area, saving 33% of the area, and significantly enables the SRAM to have the highest flexibility among the reported ones, withstanding a harsh deforming process (6000 cycles of bending at a radius of 500 μm) without performance degradation. Moreover, this design facilitates the thermal stability of the SRAM under high temperature (333 K). It also exhibits great static and dynamic performance, with the highest normalized hold noise margin of 73.6%, a maximum gain of 151.2, and a minimum static power consumption of 3.15 μW in hold operation among the reported flexible SRAMs. This demonstration provides possibilities for SRAMs to be used in advanced wearable system applications.
文章链接：
Ultraflexible Monolithic Three-Dimensional Static Random Access Memory | ACS Nano
柔性SRAM的结构与性能