Hybrid ferromagnet-semiconductor nonvolatile gate

TLDR

The paper introduces a novel magnetoelectronic device aimed at digital applications, focusing on the characteristics of a nonvolatile random access memory cell. The device is fabricated with two lithographic steps—a Hall cross and a microstructured bistable ferromagnetic film—whose edge fringe fields produce a Hall voltage in the semiconductor, and the voltage polarity is toggled by reversing the ferromagnet’s in‑plane magnetization. A micron‑scale prototype demonstrates binary outputs of 0 and 80 mV at room temperature, with performance improving as the device shrinks, suggesting that a high‑density, solid‑state NRAM could achieve nanosecond read/write times and replace DRAM and magnetic disks in most computing environments.

Abstract

A novel magnetoelectronic device for digital applications is presented, and characteristics of a Nonvolatile Random Access Memory (NRAM) cell are discussed. A prototype cell with micron dimensions and with binary output states of 0 and 80 mV has been demonstrated at room temperature. Device fabrication requires only two lithographic levels, one for a Hall cross and one for an electrically isolated, microstructured bistable ferromagnetic film. Locally strong magnetic fringe fields from the edge of the film generate a Hall voltage in the semiconductor. The sign of the fringe field, as well as the polarity of the Hall voltage, is switched by reversing the in-plane magnetization of the ferromagnet. The device is inverse scalable: output characteristics improve as dimensions shrink. A high-density, solid state NRAM with nsec read, write and access times could replace both DRAM and magnetic disk drives in most computer environments, eliminating redundancy in memory systems.