Simultaneously ultrafast and robust two-dimensional flash memory devices based on phase-engineered edge contacts

As the prevailing non-volatile memory (NVM), flash memory offers mass data storage at high integration density and low cost. However, due to the 'speed-retention-endurance' dilemma, their typical speed is limited to similar to microseconds to milliseconds for program and erase operations, restricting their application in scenarios with high-speed data throughput. Here, by adopting metallic 1T-LixMoS2 as edge contact, we show that ultrafast (10-100ns) and robust (endurance>10(6) cycles, retention>10 years) memory operation can be simultaneously achieved in a two-dimensional van der Waals heterostructure flash memory with 2H-MoS2 as semiconductor channel. We attribute the superior performance to the gate tunable Schottky barrier at the edge contact, which can facilitate hot carrier injection to the semiconductor channel and subsequent tunneling when compared to a conventional top contact with high density of defects at the metal interface. Our results suggest that contact engineering can become a strategy to further improve the performance of 2D flash memory devices and meet the increasing demands of high speed and reliable data storage. The speed-retention-endurance trade-off usually limits the performance of flash memory devices. Here, the authors report the realization of van der Waals flash memory cells based on 2H-MoS2 semiconducting channels with phase-engineered 1T-LixMoS2 edge contacts, showing program/erasing speed of similar to 10/100ns, endurance of >10(6) cycles and expected retention lifetime of >10 years.

Automated summary

The authors demonstrate the realization of ultrafast and robust memory operation in a two-dimensional van der Waals flash memory with 2H-MoS2 as the semiconductor channel and metallic 1T-LixMoS2 as the edge contact. The contact engineering strategy improves the performance of 2D flash memory devices, achieving program/erasing speed of similar to 10/100ns, endurance of >10^6 cycles, and expected retention lifetime of >10 years.