ABSTRACT
A hierarchy of volatile and non-volatile memories is used in computing systems to make an optimal trade-off between cost and performance. For over 30 years, SRAM and DRAM have been used as the working memory of this memory hierarchy, while magnetic hard disk drives HDDs) have been used for data storage. The performance gap between the HDD and main memory has already been a bottleneck that constricts system performance improvement. Today, flash-based SSD can offer fast online storage and the volume is increasing as devices scale down to smaller dimensions. However, there remains a huge performance gap of ~80 times between memory and storage. To address this problem, Intel gives out a solution, namely, Storage Class Memory (SCM). SCM acts as the bridge between the main memory and HDD. SCM has a faster speed than NAND FLASH and a higher density than DRAM. 3D RRAM gives out a low-cost and high-density structure for SCM application. This book provides a comprehensive review of the progress of 3D RRAM, which ranges from materials, devices, and arrays to in-memory computing applications. Device-level and array-level reliabilities still need to be improved before these devices are put to practical use. Since the yield and operating property of the memory chip are limited by the performance of the worst cell, the intrinsic uniformity and reliability characteristics of memory devices become critically important. The IR drop issue, disturbance issue, and thermal coupling (name a few) are also the basic problems that should be coped with, for its future commercialisation. After constant updates, 3D RRAM will revolutionise the memory hierarchy one day.
