Nanothin memory chips manufactured with 2D printing

Engineering researchers from the University of Sydney have developed a 2D printing process using liquid metals that could create new ways of creating more advanced and energy-efficient computing hardware that is manufactured at the nanoscale. The development comes amid increasing demand for memory devices, which require significant amounts of energy to produce and use.

Dr Mohammad Ghasemian, the study’s lead author, said reducing the temperature at which zirconium and hafnium become liquid is crucial for developing lower-cost electrical devices, as less energy is required. The researchers first combined tin, zirconium and hafnium in a precise ratio, thus allowing the alloy to be melted below 500°C, lower than the individual melting points for zirconium (1855°C) and hafnium (2227°C).

The liquid metal alloy has a thin oxide layer while maintaining a liquid centre, and is used to harvest the ultra-thin tin oxide nanosheets doped with hafnium zirconium oxide. “Tin is abundant, low-cost and can be used at a large scale for the manufacture of critical semiconductors, transistors and memory chips. Though hafnium zirconium oxide is a well-known ferroelectric material used in nanoscale applications, like memory devices and sensors, obtaining nanosheets using conventional techniques is both difficult and costly,” Ghasemian said.

The researchers applied the tin-zirconium-hafnium alloy to harvest the nanothin tin oxide layer doped with hafnium zirconium oxide through exfoliation — lifting it from its liquid surface — so it could then be 2D printed on a substrate as ferroelectric nanosheets. These sheets are designed to form the basis of next-generation computing hardware, such as semiconductors and memory chips. Ghasemian likened the alloy to a marble coated in ink.

“The alloy is like a solvent that allows us to remove that ink and then use it for printing. Our process allows us to harvest this precious crust layer and turn it into ultra-thin sheets, which are then used to manufacture electronics. It could be a new source of functional 2D materials which are not accessible by conventional methods. This process allows us to introduce ferroelectricity into much smaller, 2D metal oxides, allowing for the development of next-generation nanoelectronics at low temperatures,” Ghasemian said.

The research findings were published in the journal Small.

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