Control of Sub-Nanosecond Precessional Magnetic Switching in STT-MRAM Cells for SRAM Applications
Résumé
STT-MRAM are foreseen as the best contender for
DRAM replacement. STT-MRAM could also be used for SRAM
applications if switching time below 1ns could be realized in a
reliable way. In this study, we demonstrate that sub-ns switching
with final state determined by the current polarity through the
stack can be achieved in STT-MRAM cells comprising two spinpolarizing
layers having orthogonal magnetic anisotropies [1],[2].
We carried out a thorough experimental and modeling study of
these ultrafast STT-MRAM. We demonstrated that a quite
reliable switching can be achieved by increasing the cell aspect
ratio (AR) or advantageously by applying an in-plane static
transverse field on the cell. Switching in 200ps could be
demonstrated with write energy less than 100fJ.