| Posted: Oct 19, 2010 |
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Atomic-level manufacturing
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(Nanowerk News) The long-held dream of creating atomically precise three-dimensional structures in a manufacturing environment is approaching reality, according to the top scientist at a company making tools aimed at that ambitious goal. John Randall, Vice President of Zyvex Labs in Richardson, Tex., says his researchers have demonstrated a process that uses a scanning tunneling microscope tip to remove protective surface hydrogen atoms from silicon one at a time and then adds single atomic layers of silicon only to those meticulously cleared areas. Randall describes the achievement today at the AVS 57th International Symposium & Exhibition, which takes place this week in the Albuquerque Convention Center in New Mexico.
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To date, Zyvex Labs researchers have demonstrated removal of 50 hydrogen atoms per second. But with experience and innovation, Randall predicts large improvements in the speed of this limiting factor.
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"There are many paths to scale-up, including parallelism," he says. "A thousand-fold increase in speed will be fairly easy to achieve."
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Within seven years, Randall expects that Zyvex Labs will be selling initial production tools that can remove more than a million hydrogen atoms a second using 10 parallel tips at a cost of about $2,000 per cubic micrometer of added silicon (48 billion atoms).
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Applications that would benefit most from having tiny atomically precise structures include nanopore membranes, qubit structures for quantum computers and nanometrology standards. Larger-scale applications, such as nanoimprint templates, would need still further cost-performance improvements to become economically viable.
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The Zyvex process is currently used only on silicon surfaces, which are typically coated with hydrogen atoms bound to any exposed silicon atoms. The process has two steps: first, in an ultra high vacuum, a scanning tunneling microscope is directed to remove individual hydrogen atoms from only those locations where additional silicon will later be added. Second, a silicon hydride gas is introduced. A single layer of these molecules adheres to any exposed hydrogen-free silicon atoms. After deposition, the gas is removed and the process is repeated to build up as many three-dimensional layers of atomically pure silicon as is needed.
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