Bidirectional Two-Terminal Switching Device with Metal–Semiconductor–Semiconductor Structures for 4F² Spin-Transfer-Torque Magnetoresistance Random Access Memory Cell

Abstract

We proposed a novel bidirectional two-terminal selective device for realizing a 4F2 cell size for spin-transfer-torque magnetoresistance random access memory (STT-MRAM). The proposed switching device is composed of a Schottky-barrier contact and a PN junction with a metal–semiconductor–semiconductor (M/S/S) structure. The proposed M/S/S switching device provides a current density of over 106 A/cm2, which is sufficient to write the magnetic tunnel junction (MTJ), and a bilateral current flow using a punch through with an extended depletion region at a junction. Furthermore, we investigated its switching characteristics by comparing parameters such as doping profile and junction length. From this work, it is expected that an M/S/S structure will be a promising switching device for STT MRAM.