New phase change material was developed that has electrical characteristics that behave differently than those of conventional materials. This new material provides a drastic reduction in power consumption for data recording in nonvolatile random access memory (RAM).

Phase change random access memory (PCRAM) has attracted attention as a next-generation, practical, non-volatile memory. PCRAM is expected 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 °C), and needs a large amount of power for data recording.

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

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

For more information, contact Yuji Sutou, Department of Materials Science, at This email address is being protected from spambots. You need JavaScript enabled to view it..


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This article first appeared in the August, 2018 issue of Tech Briefs Magazine.

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