Electronics tend to fail when temperatures rise above about 200 degrees Celsius. Researchers at the University of Southern California have developed a new type of memory device that works reliably at 700 degrees Celsius. This temperature is hotter than molten lava. The device showed no signs of reaching its limit at the highest temperature their testing equipment could achieve.
The device is a memristor. A memristor is a tiny electronic component that can store information and perform computing operations at the same time. It held data for over 50 hours at 700 degrees Celsius without refresh. It survived more than one billion switching cycles. It ran on 1.5 volts with operation speeds of tens of nanoseconds.
How the device resists high heat
The memristor is built as a sandwich of extreme materials. It uses tungsten, the metal with the highest melting point, as the top layer. The middle is a thin layer of hafnium oxide ceramic. The bottom layer is graphene. Graphene is a sheet of carbon atoms only one atom thick.
In standard devices, heat causes metal atoms from the top layer to migrate through the ceramic and connect to the bottom layer. This creates a short circuit that ruins the device. Graphene stops the atoms from anchoring because its surface chemistry repels them. Scientists used advanced microscopy, spectroscopy, and computer simulations to understand the atomic process exactly.
The new device could find use in space missions to planets like Venus where surface heat reaches 500 degrees Celsius. It may also help in deep-earth drilling for geothermal energy and in nuclear or fusion power systems. For artificial intelligence, memristors can perform matrix multiplication directly. Matrix multiplication is a key math operation that combines numbers in grids and makes up most of the work in AI tasks. This method is faster and uses less energy than traditional computing.
This research is published in Science.