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.