The Pursuit of Atomistic Switching and Cross Point Memory

With the disclosure of the Ovonic Threshold Switch (OTS) [1] and chalcogenide memory technology [2] in late '60s, the pursuit of nonvolatile memory beyond electrostatic storage escalated across the industry. Various two-tenninal switches exhibiting nonlinear I-V characteristics have been explored as a cost-effective solution. 40 years later, an experimental attempt to integrate chalcogenide switch and memory for a 64Mb array was successfully demonstrated [3]. Further advances to the memory element achieved fast access and tight statistical control of states [4]. This novel chalcogenide memory was a deliberate departure from the existing phase change memory (PCM) [5], It illustrated a vision of a new class of memory, bridging the gap between DRAM and SSD. Another decade later, 3D XPoint Memory is commercialized.