Researchers at the University of Southern California have demonstrated a new type of electronic memory device that works at temperatures as high as 700°C. That was the highest temperature their equipment could test, rather than a proven limit for the device.
The device is a memristor, a tiny electronic part that can store information and perform computing operations. Think of it as a sandwich: two layers that conduct electricity, called electrodes, with a thin ceramic layer between them. The team used tungsten for the top electrode, hafnium oxide ceramic in the middle, and graphene for the bottom electrode. Graphene is a sheet of carbon just one atom thick.
In laboratory tests, the device held data for more than 50 hours at 700°C without needing to be refreshed. It also survived more than one billion switching cycles at that temperature. It ran on just 1.5 volts, with switching speeds measured in tens of nanoseconds.
Why did it survive? In conventional devices of this type, heat can cause metal atoms to move through the ceramic layer and form a permanent connection to the bottom electrode. This causes the device to fail. In the new device, tungsten atoms did not bond strongly to graphene, helping prevent that failure.
The technology could be useful in space exploration, geothermal drilling, and industrial environments where electronics face intense heat. The research, published in Science, points toward memory devices for such conditions.