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Atomically Precise Manufacturing using STM Based Patterning

Friday, November 6, 2015, 11:00 AM - 12:30 PM
Nedderman Hall Room 202

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Josh Ballard, Research Scientist, ZyVex Labs


Improvements in manufacturing precision have driven technological advancements in many fields ranging from the concept of interchangeable parts to our current mobile computing revolution.  With the Atomically Precise Manufacturing (APM), we are performing the basic research to enable continued down-scaling of feature production, and we will translate the techniques that we develop into feasible manufacturing processes.

Hydrogen Depassivation Lithography (HDL) is central to our APM efforts.  Taking advantage of careful analysis of the Si(100)-H surface we move the tip--both in imaging and in lithography modes--over the surface with atomic precision, enabling the flexible creation of a wide variety of HDL patterns. This talk will discuss technical details related to the tip positioning, tip fabrication, and the lithography process in general.

Pattern transfer techniques will also be discussed. First, we have developed a cyclic high temperature process for epitaxy of Si and Ge on Si, comprising HDL followed by deposition of disilane which adsorbs into the atomically defined patterns.  Structures of epitaxial Si several monolayers tall have been built within patterns on the order of 30nm on a side to demonstrate the feasibility of the process. Selective atomic layer deposition (ALD) for hard mask fabrication will also be described. Using an ALD chemistry of TiCl4 + H2O, it has been shown that TiO2 will deposit on SiO2 or clean Si(100) while being suppressed on Si(100)-H. Growth on HDL patterns is shown, along with 3D nanostructures etched into Si(100) using reactive ion etching or a new low energy electron enhanced etching process. Structures with CD down to 6 nm have been fabricated, with subfeature sizes down to less than 2 nm possible. Future prospects for using 3D nanostructures will also be discussed.

Josh BallardBIO

Josh Ballard graduated from Harvard with an A.B. in Psychology and obtained a Ph.D in Physical Chemistry with a Master's certification in Optical Science and Engineering at the University of Colorado (Boulder and JILA) in 2003. His dissertation, titled, “Dynamic Phase and Population Control of State Selected Wave Packets in Li2”, focused on using coherent control of ultrafast laser pulses to code information into multiplexed energy states in Li2. In the next three years thereafter, he was a Beckman Fellow at the Beckman Institute of Advanced Science and Technology at the University of Illinois (Urbana-Champaign), where he worked with Joe Lyding and Martin Gruebele to develop a laser-assisted STM to perform single-molecule adsorption spectroscopy and laser-enhanced hydrogen depassivation lithography. Following this, he helped develop a compact optical platform for aircraft-based in-situ ozone measurements at the National Oceanographic and Atmospheric Administration. Over the last seven years, he has led the development of the primary research tools at Zyvex Labs with the goal of turning STM-based atomically precise manufacturing into a reality. In the time at Zyvex Labs, Ballard has led advances in STM instrumentation, surface patterning, and processing to transfer atomically precise patterns into useful nanostructures.

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