Here’s a tip:
Technique yields durable diamond probes
Nano-foundry technique. Image courtesy of IBM Research-Zurich. |
When a team of university and industry researchers tried a novel, foundry-style mold-filling technique to make nanoscale devices, they realized they had discovered a gem: They used their process to fabricate ultra-hard, wear-resistant nanoprobes out of a material much like diamond.
On a larger scale, materials that look smooth still abrade because of slight irregularities and defects on their surfaces. Now zoom in: At the nanoscale, atoms rub off one at a time, challenging researchers who build devices just tens of atoms wide. Silicon-containing diamondlike carbon, or Si-DLC, could solve this problem.
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Engineering Physics Distinguished Research Professor Kumar Sridharan developed the “nano foundry” technique. He started with an IBM silicon-on-insulator wafer previously etched with sharp, pyramid-shaped “molds.” Then, he used plasma immersion ion implantation and deposition, a room-temperature deposition process, to fill the molds.
The technique works somewhat like the way in which a snowfall blankets the ground. In this case, the “snow” is ionized hexamethyl disiloxane, a liquid precursor to Si-DLC that gasifies in the plasma chamber and packs neatly into the molds. Fabricated on standard silicon microcantilivers, the ultrasharp tips in wear tests were 3,000 times more wear-resistant than silicon tips.
The team, which also included researchers from the University of Pennsylvania and IBM Research-Zurich, published details of its research January 31 in the advance online edition of Nature Nanotechnology.