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takyon writes:

https://www.nist.gov/news-events/news/2017/08/gentle-touch-nist-scientists-push-us-closer-flash-memory-successor

[Resistive random access memory (RRAM)] could form the basis of a better kind of nonvolatile computer memory, where data is retained even when the power is off. Nonvolatile memory is already familiar as the basis for flash memory in thumb drives, but flash technology has essentially reached its size and performance limits. For several years, the industry has been hunting for a replacement.

[...] One hurdle is its variability. A practical memory switch needs two distinct states, representing either a one or a zero, and component designers need a predictable way to make the switch flip. Conventional memory switches flip reliably when they receive a pulse of electricity, but we're not there yet with RRAM switches, which are still flighty.

[...] This randomness cuts into the technology's advantages, but in two recent papers, the research team has found a potential solution. The key lies in controlling the energy delivered to the switch by using multiple, short pulses instead of one long pulse.
Typically, chip designers have used relatively strong pulses of about a nanosecond in duration. The NIST team, however, decided to try a lighter touch—using less energetic pulses of 100 picoseconds, about a tenth as long. They found that sending a few of these gentler signals was useful for exploring the behavior of RRAM switches as well as for flipping them.

"Shorter pulses reduce the variability," Nminibapiel said. "The issue still exists, but if you tap the switch a few times with a lighter 'hammer,' you can move it gradually, while simultaneously giving you a way to check it each time to see if it flipped successfully."

Characteristics of Resistive Memory Read Fluctuations in Endurance Cycling (DOI: 10.1109/LED.2017.2656818) (DX)

Impact of RRAM Read Fluctuations on the Program-Verify Approach (DOI: 10.1109/LED.2017.2696002) (DX)

Original Submission