Spin-Based Computing: Device Concepts, Current Status, and a Case Study on a High-Performance Microprocessor

As the end draws near for Moore's law, the search for low-power alternatives to complementary metal-oxide-semiconductor (CMOS) technology is intensifying. Among the various post-CMOS candidates, spintronic devices have gained special attention for their potential to overcome the power and performance limitations of CMOS. In particular, all spin logic (ASL) technology, which performs Boolean operations and transfers the output in the spin domain, has been proposed for enabling new capabilities-such as high density, low device count, and nonvolatility-that were previously impossible with CMOS technology. In this paper, first we provide an overview of the history and the current status of the various spintronic devices being pursued by the research community. Then, we describe how spin-based components are integrated into a computing system and the advantages that result. We use a hypothetical spintronic-based Intel Core i7 as a test vehicle to compare the system-level power requirements of ASL- and CMOS-based systems, taking into consideration the unique demands of spin-based interconnects. We conclude with a brief analysis of current limitations and future directions of spintronic research.

I. INTRODUCTION

Complementary metal–oxide–semiconductor (CMOS) scaling, otherwise known as Moore's law, has transformed the way we create, process, communicate, and store information in the digital age [1]– [4]. As we approach the physical limits of CMOS technology, however, it has become increasingly difficult to manage power dissipation issues [5]– [7]. The urgent need for low-power alternatives has led to a flurry of research activity on novel post-CMOS device technologies [8], [9]. Among the various post-CMOS candidates, spintronic devices have gained special attention for their potential to overcome the power and performance limitations of CMOS [10]– [12]. From a computing perspective, spintronic devices potentially have unique features—such as zero static power, instant wakeup, reduced device count, and lower switching energy—that were difficult to achieve using CMOS technology. Another intriguing feature of spintronic devices is that they could augment existing Boolean computing methods by enabling an entirely new class of architectures such as processor-in-memory, logic-in-memory, and analog/neuromorphic computing [13]– [15].