Emerging CMOS Compatible Magnetic Memories and Logic

Abstract

As scaling of the feature size - the main driving force behind an outstanding increase of the performance of modern electronic circuits - displays signs of saturation, the main focus of engineering research in microelectronics shifts towards finding new paradigms. Any future solution must be scalable and energy efficient while delivering high performance, superior to that of CMOS-based circuits. In order to benefit from the outstanding potential of highly advanced silicon processing technology, any new solution must be CMOS compatible. Emerging nonvolatile memories, including magnetoresistive memories, satisfy the necessary requirements: purely electrical addressability, simple structure, high endurance and fast operation. In this work we present the recent developments in the research of spin-transfer torque and spin-orbit torque random access memories and give a brief overview of spin-based logic. Here, the advantages and challenges of these two main contenders in the magnetic memory field are described and the current technological trends are noted. Areas facing computational challenges due to the long-range interaction of the demagnetizing field are highlighted and an existing solution is presented. The use of reinforcement learning to optimize handling of a purely electrically controllable spin-orbit torque memory cell is introduced and first results showing the switching reliability of an optimized switching pulse sequence under thermal fluctuations are reported.

Keywords

• Digital spintronics
• spin-transfer torque (STT)
• spin-orbit torque (SOT)
• magnetoresistive random access memory (MRAM)
• in-memory computing
• reinforcement learning (RL)