Magnetic Random Access Memory for Embedded Computing

摘要

The goal of this research was to develop an embedded magnetic memory technology to be integrated into Complementary Metal Oxide Semiconductor (CMOS) integrated circuit fabrication process to provide radiation-hard, logic elements and small random-access memories. The goal is not to provide large scale, bulk memory, but latches and flip flops that serve as state and data registers for sequential logic, and configuration registers for configurable logic. The benefits to spacecraft systems include the ability to power-down a subsystem while retaining system state, thus saving energy until the subsystem is required. The subsystem can then be powered-up and begin operating in milliseconds. The technology is based on a unique, PacMan-shaped magnetic tunneling junction (MTJ) cell developed at the University of Idaho. The focus of this research is to refine the PacMan cell to make it practical for integration into CMOS circuits, to develop CMOS circuits that employ the magnetic cells, and to integrate the cells onto a CMOS process. The process produced two circuit designs based on magnetic memory elements: a magnetic latch, and a magnetic shadow memory to serve as a backup to volatile electronic memory.