Introduction

Abstract

Computer memory is any physical device capable to store data temporarily or permanently. It covers from fastest, yet most expensive, static random-access-memory (SRAM) to cheapest, but slowest, hard drive disk, while in between there are many other memory technologies that make trade–offs among cost, speed, and power consumption. However, the large volume of memory will experience significant leakage power, especially at advanced CMOS technology nodes, for holding data in volatile memory for fast accesses. The spin–transfer torque magnetic random-access memory (STT–RAM), a novel non-volatile memory– (NVM) based on spintronic devices, has shown the great benefits on power–wall issue compared to traditional volatile memories. In addition, in traditional Von–Neumann architecture, the memory is separated from the central processing unit. As a result, the I/O congestion between memory and processing unit leads to the memory-wall issue, and ultimate solution requires a breakthrough on memory technology. The novel in–memory architecture is the solution of memory–wall issues that both logic operation and data storage are located inside memory. This chapter reviews the existing semiconductor memory technologies and traditional memory architecture first, and then introduces the spintronic memory technologies as well as the in-memory architecture.