Korean scientists have created a hybrid of RAM and flash memory with ultra-low consumption

In one of the April issues of the magazine Nature An article by scientists from South Korea was published, in which they talked about one very promising development. The discovery can be thought of as the discovery of the Holy Grail of memory – cells that are both fast like DRAM and non-volatile like NAND. According to the most conservative estimates, the new memory consumes 15 times less than its analogues produced today, and it couldn’t be cheaper to produce it. Not a memory, but a dream.

Let us clarify right away that we are talking about phase-change memory or PCM (phase-change memory). A PCM cell is a certain volume of a substance that can be either in an amorphous state or in a crystalline state. In the first case, there is no movement of electrons in the cell – there is real chaos there, and in the second, it is an ordered structure that is capable of conducting current. The cell moves from one state to another using local heating, which is initially difficult to call an energy-efficient solution. Only the most advanced technical processes, when the cell is as small as possible, and customers who are ready, without haggling, to pay for memory that is resistant to various environmental influences, for example, insensitive to radiation, are saved.

Theoretically, 3D XPoint (Optane) memory, which was unfairly excluded from Intel’s plans, can be considered PCM memory, although it can also be classified as ReRAM or resistive memory. In principle, the essence remains the same, and it has exactly the same problems – expensive production and poor scaling.

But it’s too early to write off PCM. Scientists from the Faculty of Electrical Engineering at KAIST University have developed a technical process during which the PCM junction is formed electrically (during the migration of atoms of the substance, apparently). Such production does not require expensive lithography and all the best. Using a new technical process, the junction dimensions were reduced to 5 nm. And this despite the fact that memory manufacturers, over the past 20 years of development and production of PCM, have only approached 40 nm cells, using technical processes common in production.

Obviously, a 5nm PCM cell will consume less than a 40nm one. During the experiments, a prototype of the new PCM memory, which “fast like DRAM and non-volatile like NAND flash”showed energy consumption 15 times less than in the case of modern analogues.

“The phase change memory device we developed is significant because it offers a new approach to solving problems in memory device manufacturing at significantly increased manufacturing costs and energy efficiency. We expect that our research will form the basis of future electronic engineering, enabling the implementation of various products, including high-density 3D vertical memory and neuromorphic computing systems, as it opens up the possibility of choosing from a variety of materials,” — the developers modestly presented a new product, which, if successful, will lead to a revolution in the field of operational and long-term data storage.