Reliable Sub-Nanosecond Switching in Magnetic Tunnel Junctions for MRAM Applications

Abstract

We demonstrate reliable sub-nanosecond switching in two-terminal spin transfer torque magnetoresistive random access memory (STT-MRAM) devices by using double spin-magnetic tunnel junctions (DS-MTJs). A write-error-rate (WER) of 1<italic>E</italic> <inline-formula> <tex-math notation="LaTeX">$$-$$</tex-math> </inline-formula>6 was achieved in 194 devices with 250-ps write pulses and tight distributions. The WER <inline-formula> <tex-math notation="LaTeX">$$=$$</tex-math> </inline-formula> 1<italic>E</italic> <inline-formula> <tex-math notation="LaTeX">$$-$$</tex-math> </inline-formula>6 was also demonstrated over a temperature range of <inline-formula> <tex-math notation="LaTeX">$$-$$</tex-math> </inline-formula>40 <inline-formula> <tex-math notation="LaTeX">$$^\circ$$</tex-math> </inline-formula>C&#x2013;85 <inline-formula> <tex-math notation="LaTeX">$$^\circ$$</tex-math> </inline-formula>C in a single device with 225-ps write pulses. No degradation was observed after 1<italic>E</italic>10 write cycles in selected single devices, written with 250-ps write pulses. We compare the DS-MTJ device switching performance with the published results from the state-of-the-art three-terminal spin&#x2013;orbit torque (SOT) MRAM devices and show a 10<inline-formula> <tex-math notation="LaTeX">$$\times$$</tex-math> </inline-formula> reduction in switching current density (<inline-formula> <tex-math notation="LaTeX">$$\textit{J}_{\text{c}}$$</tex-math> </inline-formula>) and 3&#x2013;10<inline-formula> <tex-math notation="LaTeX">$$\times$$</tex-math> </inline-formula> reduction in power consumption for devices with similar energy barriers (<inline-formula> <tex-math notation="LaTeX">$$\textit{E}_{\text{b}}$$</tex-math> </inline-formula>).