Waterloo Institute for Nanotechnology
Mike & Ophelia Lazaridis Quantum-Nano Centre, QNC 3606
University of Waterloo
200 University Avenue West,
Waterloo, ON N2L 3G1
519-888-4567, ext. 38654
win-office@uwaterloo.ca
Research interests: micro-nanofabrication, lithography, MEMS fabrication, microneedle, AFM probe fabrication, terahertz photoconductive antenna, dry plasma etching
Professor Bo Cui received his BS in Physics from Peking University, China, in 1994. After two years of graduate study in the same department, he moved to the University of Minnesota, then to Princeton University in 1998, where he earned his master’s degree in 2000 and PhD in 2003 from the Nanostructure Laboratory (led by Professpr Stephen Y. Chou), Department of Electrical Engineering. After completing his PhD, Cui joined the National Research Council of Canada, Industrial Materials Institute in Boucherville in 2003. Cui joined the Department of Electrical and Computer Engineering (Nanotechnology Engineering program) in 2008.
Cui leads the Waterloo Nanofabrication Group whose research is focused on nano- and microstructure fabrication using Nano-Imprint Lithography (NIL) and electron beam lithography, thin film deposition and etching, with applications in biomedical, nanoelectric and other areas.
Professor Cui focuses his research on micro-nanofabrication using cleanroom facilities including electron beam lithography, focused ion beam, ICP-RIE/deep RIE, laser direct writing (maskless lithography), and physical/chemical vapor deposition. His group has extensive collaboration with industries in the field like biomedical devices/sensors and terahertz spectroscopy.
Electron beam lithography
Electron beam lithography is the most popular nanolithography techniques for R&D. It utilizes a focused electron beam to expose a resist material and can obtain readily sub-10nm resolution. One challenge in nanofabrication is to pattern on non-flat surfaces, which is desired in many fields such as MEMS, bio-sensors, electronic devices, and optical devices. This is because the usual film coating method spin-coating can form a uniform film only on flat surfaces. My group has developed two methods to enable nanofabrication on irregular surfaces using electron beam lithography. The first one utilizes polystyrene negative resist that can be coated by thermal evaporation on any surfaces. The second method employs a monolayer polymer brush resist that can be formed on any surface with extremely uniform film thickness.
MEMS/Microneedle fabrication
Compared to the conventional hypodermic needle, microneedle array causes negligible pain since it enters a limited depth (<~500 mm) without triggering nerve endings located deeper in the skin. It can be used for drug delivery or body fluid interrogation for point-of-care testing. In collaboration with a local startup company working on allergy test, we successfully developed the microfabrication process of hollow silicon microneedles with a cone shape and diameter at apex <5 mm, using deep Si etching, lithography, and needle sharpening by wet etching. We also developed a fabrication process to create Si “in-plane” microneedles that can reach mm-scale length.
AFM probe fabrication
AFM (atomic force microscope) is widely used for topographical structure characterization with ~1nm imaging resolution. It employs a probe tip to scan/feel the specimen surface. One serious issue with AFM imaging is the intrinsic artifact in the AFM image when mapping a non-flat surface where the tip cannot fully follow the sample surface. The natural solution to this issue is by using thin and high aspect ratio tips that can follow the sample surface more precisely. My group has developed a high throughput and low cost process for the fabrication of such high end tips and this technology is being commercialized.
Terahertz spectroscopy
Terahertz (THz) electromagnetic waves have frequencies of order 10^12 Hz and wavelengths order 100 um. Many materials including organic materials, explosives, pharmaceutical compounds and biological agents have distinct signatures in the terahertz frequencies, thus THz spectroscopy. This distinct characteristics of terahertz radiation, along with recent advances in the enabling technologies, have created the opportunity for the terahertz technology to provide unique solutions to many critical industrial problems. At the heart of the THz spectroscope is the THz antenna (transmitter and receiver). In collaboration with a local company, my group has successfully developed the fabrication process for photoconductive antenna with various device configurations (lateral device, mesa structure, vertical device). The THz chip we fabricated has been successfully integrated into the company’s product.
Recent publications include:
Waterloo Institute for Nanotechnology
Mike & Ophelia Lazaridis Quantum-Nano Centre, QNC 3606
University of Waterloo
200 University Avenue West,
Waterloo, ON N2L 3G1
519-888-4567, ext. 38654
win-office@uwaterloo.ca
The University of Waterloo acknowledges that much of our work takes place on the traditional territory of the Neutral, Anishinaabeg and Haudenosaunee peoples. Our main campus is situated on the Haldimand Tract, the land granted to the Six Nations that includes six miles on each side of the Grand River. Our active work toward reconciliation takes place across our campuses through research, learning, teaching, and community building, and is co-ordinated within our Office of Indigenous Relations.