Old silicon learns new tricks

news
14/01/2021

Researchers fabricated regular arrays of iron-coated silicon crystals that are atomically smooth. The defect-free pyramidal composition of the crystals impart magnetic properties that will enhance the functionality of 3D spintronics and other technologies.

Ultrasmall integrated circuits have revolutionized mobile phones, home appliances, cars, and other everyday technologies. To further miniaturize electronics and enable advanced functions, circuits must be reliably fabricated in three dimensions. Achieving ultrafine 3D shape control by etching into silicon is difficult because even atomic-scale damage reduces device performance. Researchers at Nara Institute of Science and Technology (NAIST) report, in a new study seen in Crystal Growth and Design, silicon etched to adopt the shape of atomically smooth pyramids. Coating these silicon pyramids with a thin layer of iron imparts magnetic properties that until now were only theoretical.

NAIST researcher and senior author of the study Ken Hattori is widely published in the field of atomically controlled nanotechnology. One focus of Hattori's research is in improving the functionality of silicon-based technology.

"Silicon is the workhorse of modern electronics because it can act as a semiconductor or an insulator, and it's an abundant element. However, future technological advances require atomically smooth device fabrication in three dimensions," says Hattori.

A combination of standard dry etching and chemical etching is necessary to fabricate arrays of pyramid-shaped silicon nanostructures. Until now, atomically smooth surfaces have been extremely challenging to prepare.

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