Ultralow power consumption for data recording

This new material allows a drastic reduction in power consumption for data-recording in non-volatile random access memory.

Phase change random access memory, PCRAM, has attracted attention as a next generation practical non-volatile memory. PCRAM isexpected to not only replace flash memory but also to be used for storage-class memory, which can mitigate the difference in latencies between DRAM and flash memory.

The principle of PCRAM operation relies on the change in electrical resistance between high resistance amorphous and low resistance crystalline states in phase change material.

Ge-Sb-Te (GST) is well known as a phase change material for PCRAM application.

GST can operate at high speed but has poor data retention at high temperatures (~ 85 ºC) and needs a large amount of power for data-recording.

This newly developed phase change material, Cr₂Ge₂Te₆, exhibits an inverse resistance change from low resistance amorphous to high resistance crystalline states. The researchers demonstrated that the Cr₂Ge₂Te₆ can achieve a reduction of more than 90% in power consumption for data-recording compared to using conventional GST memory cell.

Simultaneously, Cr₂Ge₂Te₆ was found to combine a faster operation speed (~30 ns) and a higher data retention property (over 170 ºC) than conventional materials. Comparison with other reported materials indicates that Cr₂Ge₂Te₆ can break the trade-off relationship between data retention and operation speed.

The researchers believe that the inverse resistance change Cr₂Ge₂Te₆ is a breakthrough material for PCRAM with combined low operation energy, high data retention and fast operation speed.

This work was supported by KAKENHI (Grant Nos. 15H04113 and 17J02967) , JSPS and KPFK under the Japan-Korea Basic Scientific Cooperation Program. It was also supported by the Kato Foundation for Promotion of Science.