Advanced 3-D Fabrication on the Nanoscale
Owen Hildreth, NRC post-doctoral fellow, National Institute of Standards and Technology
Tuesday, Feb. 18, 2014
Goldwater Center (GWC) 487 [map]
Fabricating 3-D nanostructures in an affordable, scalable manner is one of the hurdles slowing the integration of nanotechnology into real-world devices. In order to overcome this limitation, new techniques are needed that are capable of fabricating complex 3-D geometry in a manner that is affordable for both large and small volume production. This talk discusses two new approaches to 3-D nanofabrication, focusing primarily on Metal-assisted Chemical Etching (MaCE) as a subtractive or “top-down” fabrication technique and then highlighting recent advances in ElectroHydroDynamic (EHD) printing that will bring low-cost, additive manufacturing to the nanoscale.
MaCE is a relatively new etching technique that is capable of etching 3-D nanostructures with 1 – 2 nm feature resolutions even over aspect ratios greater than 500:1. With etch rates upwards of 1 µm/sec, MaCE leverages the high throughput of traditional wet and dry chemical etching techniques but introduces a new, “traveling catalyst” paradigm that opens up new opportunities for 3-D fabrication. This presentation details the capabilities and use of MaCE to fabricate 3-D structures including spirals with controlled chirality and vertically aligned thin-film structures. The basic chemistry will be discussed along with the mechanisms driving catalyst motion and the processing conditions necessary to fabricate these advanced structures. Current applications in photovoltaics and x-ray zone-plate lens fabrication will also be highlighted.
The seminar will conclude with a discussion on EHD printing as a direct-write, additive 3-D nanofabrication platform. This section of the talk will summarize the basic principles of EHD printing and highlight how new ink chemistries, improved understanding of jetting dynamics, and the development of field-modulated drop positioning will help unlock the potential of this process to radically simplify the way we fabricate 3-D structures on the nanoscale.
Owen Hildreth received his B.S. in Mechanical Engineering from the University of California, San Diego in 2002 and then worked as mechanical engineer for five years designing and testing consumer devices. In 2007, he returned to school and, working under C. P. Wong, received his Ph.D. in Materials Science and Engineering from the Georgia Institute of Technology in 2012. He is currently a National Research Council Post Doctoral Fellow at the National Institute of Technology. Specializing in scalable nanofabrication, he has published nineteen technical articles in peer-reviewed journals, conference proceedings, and book chapters. He also holds one U.S. patent.