Development of Spin-Orbit Torque Magnetic Random Access Memory with Eight-Inch Fab Processes
Chi-Feng Pai1*, I. J. Wang2, S. Z. Rahaman2, Y. S. Chen2, D. Y. Wang2, Y. C. Hsin2, Y. J. Chang2, H. H. Lee2, G. L. Chen2, S. Y. Yang2, Y. C. Kuo2, Y. H. Su2, M. J. Kao2, C. I. Wu2
1Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
2Electronic and Optoelectronic System Research Laboratories, Industrial Technology Research Institute, Hsinchu, Taiwan
* Presenter:Chi-Feng Pai,
To highly improve the reading and writing reliability of magnetic tunnel junction (MTJ) for nonvolatile cache memory applications, spin-orbit torque (SOT) switching with separated read/write paths is regarded as a promising solution. Applying the current through an ultra-thin (~3nm) heavy metal layer can optimize the spin Hall current efficiency. To acquire high switching uniformity, a stepped in-plane MTJ compatible to 8-inch CMOS process line is adopted in this work to solve the issue of non-uniform spin Hall metal caused during the etching process. The spin Hall metal connects to the metal pads by Cu trench, which greatly reduces the resistance of bottom electrode. The true SOT switching against Oersted field is experimentally proven through the analysis of magnetic moment direction of parallel (P) and anti-parallel (AP) resistance states. The switching current densities for the P-to-AP and AP-to-P processes are comprehensively investigated with various pulse widths and under elevated temperatures.

Keywords: spintronics, spin Hall effect, spin-orbit torque, MRAM, MTJ