Have you ever felt your smartphone getting hot after using it a lot or watched the battery drop at the worst possible moment? A big reason is the electronic circuits and memory inside the device, which consume energy and emit heat while working.
At the most basic level, computer memory stores information as 0s and 1s by controlling how easily electricity passes through matter. If scientists can design memory that requires much less power, they could dramatically reduce the energy demands of phones, computers, and other electronic devices.
A new approach to low-power memory
One idea aimed at solving this problem dates back to 1971, when researchers proposed ferroelectric tunnel junctions (FTJs). This type of memory relies on ferroelectricity, a property that allows a material to switch its internal electrical polarization. Changing this polarity affects how easily current can flow, allowing the device to store data.
Despite that promise, traditional materials used in this type of memory have struggled as devices have become smaller. As components became smaller, performance often decreased, limiting technology advancements.
Hafnium oxide enables ultra-compact memory
A key breakthrough occurred in 2011, when scientists discovered that hafnium oxide, a widely used material, can retain electrical polarization even when it is very thin. Based on this discovery, Professor Yutaka Mashima and his team at Tokyo University of Science set out to develop an extremely small memory device with a diameter of just 25 nanometers, approximately 1/3000 times the thickness of a human hair.
Solving leaks at the nanoscale
Shrinking memory to this scale poses significant challenges. Current tends to leak through boundaries between small crystals in materials, and this has long prevented further miniaturization.
Instead of trying to get around this problem, the researchers took a different approach. They made the devices even smaller and reduced the effects of their crystal boundaries.
They also developed a new manufacturing method that naturally forms a semicircle by heating the electrode. This design created a near-single-crystal structure with fewer boundaries where leaks could occur.
The breakthrough that smaller is better
By combining this structural design with extreme miniaturization, the team achieved the device’s high performance. More importantly, they demonstrated the unexpected. In fact, the smaller the memory, the better the performance, overturning a long-held assumption in electronics.
What this means for future devices
If this technology is used in the real world, it could have far-reaching implications. Devices like smartwatches could operate for months on a single charge, and networks of connected sensors could operate without the need for frequent battery changes.
In artificial intelligence (AI), this type of memory can support faster processing while using much less energy. Hafnium oxide is already compatible with existing semiconductor manufacturing, so integrating this new memory into everyday electronics could happen relatively quickly.
Comments from researchers
Challenging what is considered to be the limit of science, such as “We can’t make it any smaller,” or “If we make it smaller, it will break,” is like walking in the dark. It’s an ongoing struggle. However, by questioning traditional assumptions and exploring new ways to overcome these barriers, we were able to discover entirely new perspectives. We hope that this result will stimulate the curiosity of the young people who will lead the future, and contribute to building a better world. — Yutaka Mashima, Professor, Materials and Structures Laboratory, Research Organization, Tokyo University of Science.
