For the first time, scientists at IBM Research have demonstrated reliably storing 3 bits of data per cell using a relatively new memory technology known as phase-change memory (PCM).

The current memory landscape spans from venerable DRAM to hard disk drives to ubiquitous flash. But in the last several years PCM has attracted the industry’s attention as a potential universal memory technology based on its combination of read/write speed, endurance, non-volatility and density.

For example, PCM doesn’t lose data when powered off, unlike DRAM, and the technology can endure at least 10 million write cycles, compared to an average flash USB stick, which tops out at 3,000 write cycles. 

This research breakthrough provides fast and easy storage to capture the exponential growth of data from mobile devices and the Internet of Things.

IBM scientists envision standalone PCM as well as hybrid applications, which combine PCM and flash storage together, with PCM as an extremely fast cache. For example, a mobile phone’s operating system could be stored in PCM, enabling the phone to launch in a few seconds. In the enterprise space, entire databases could be stored in PCM for blazing fast query processing for time-critical online applications, such as financial transactions.

Machine learning algorithms using large datasets will also see a speed boost by reducing the latency overhead when reading the data between iterations.

Previously scientists at IBM and other institutes have successfully demonstrated the ability to store 1 bit per cell in PCM, but at the IEEE International Memory Workshop in Paris, IBM scientists are presenting, for the first time, successfully storing 3 bits per cell in a 64k-cell array at elevated temperatures and after 1 million endurance cycles.

“Phase change memory is the first instantiation of a universal memory with properties of both DRAM and flash, thus answering one of the grand challenges of our industry,” said Dr. Haris Pozidis, an author of the paper and the manager of non-volatile memory research at IBM Research - Zurich. “Reaching 3 bits per cell is a significant milestone because at this density the cost of PCM will be significantly less than DRAM and closer to flash.”