惠普发现忆阻器机制

"What we have discovered is that an electric field and a current act together to enable a memory device that can both be switched very rapidly and hold its state indefinitely," said Williams. "Not only does an applied voltage drive the migration of oxygen vacancies in the device, but at the same time there is a current that heats it up to about 300 degrees Celsius—just enough to turn the amorphous film into a crystalline film."

根据HP的说法，备忘录被吹捧为未来的“通用内存”设备，因为它们的速度与DRAM一样快，闪光灯和耐用性和仅读书的持久性。作为电阻，电容器和电感器之后的第四个基本被动电路元件，临时器通过在氧化物薄膜中引入或去除氧气空位来保留高或低抗性状态。

Synchrotron x-rays probed the memristor in a 100 nanometer region with concentrated oxygen vacancies (right, shown in blue) where the memristive switching occurs. Surrounding this region a newly developed structural phase (red) was also found to act like a thermometer revealing how hot the device becomes when read or written.

Using their favorite formulation—titanium oxide—HP recently used high-energy synchrotron x-rays to correlate the device’s electrical characteristics with its atomic structure, chemistry, and temperature in three dimensions. The until now unforeseen conclusion was that a hot spot near the bottom electrode heats enough during switching to induce a crystallization of the oxide. After driving out vacancies (for a 1) or introducing them (for a 0) in one-to-two nanometers thick region, the film cools in an annealing-like like process which leaves the film in a fixed crystalline state that should remain that way indefinitely.

"In testing, we have switched these devices over 30 billion times and counting, with no degradaton in their ability to retain information," said Williams.

惠普目前working with Hynix Semiconductor Inc., to create commercial memories based on memristive technology.