Researchers build 3D structures in silicon using gold

Scientists have developed a method to model three-dimensional shapes in silicon using chemical lithography alone. The development offers the possibility to make nanostructures in silicon semiconductors.

In this case, the nanostructures consist of silicon nano-spines with a skeletal structure. These structures could be applied in the future in stretchable bioelectronics or skin-like adhesives. To obtain these structures, the researchers used gold as a catalyst to grow silicon nanowires via CVD.

During the growth of the wires, the gold spreads over the silicon surface. By adjusting the concentration of the gold particles, think of the amount of atoms, the researchers were able to influence the rate of diffusion, allowing them to select which parts of the nanowires should be coated with gold. The gold coating then acted as a lithographic mask when etching the wires with potassium hydroxide.

The end result was that the researchers’ technique was able to print complex spines with ridges, notches and skeletal structures using chemical techniques. Combined with hydrogels that resemble body tissue, these spines held up much better than ‘normal’ silicon needles. In this way, certain implants and other skin-like adhesives can potentially be made more robust.

The research is published Thursday in the journal Science.

Update 9.33: A few things have been adjusted and made clearer in response to Stygeon’s post.