In-situ measurements of nanoscale dynamics using a conventional microscope

ECE Seminar: In-situ measurements of nanoscale dynamics using a conventional microscope

Starts at: October 31, 2013 4:30 PM

Ends at: 5:30 PM

Location: Scaife Hall Auditorium

Speaker: Lynford L. Goddard

Affiliation: Associate Professor, Electrical and Computer Engineering, University of Illinois

Refreshments provided: Yes

Details:Abstract: We present epi-illumination diffraction phase microscopy (epi-DPM) as a non-destructive optical method for monitoring physical processes in real time and with nanometer level sensitivity. The method uses a compact Mach-Zehnder interferometer to recover quantitative amplitude and phase maps of the field reflected by the sample mounted in a conventional microscope. The low temporal noise of 0.6 nm per pixel at 8.93 frames per second enabled us to collect a three-dimensional movie showing the dynamics of semiconductor wet etching and thereby accurately quantify non-uniformities in the etch rate both across the sample and over time. We have also observed water droplet evaporation from surfaces, the expansion and deformation of materials, and found isolated defects in patterned semiconductor wafers. Finally, by displaying a gray-scale digital image on the sample with a computer projector, we performed photochemical etching to define arrays of microlenses and complex geometrical profiles such as a 3-dimensional Archimedean spiral.

Biography: Dr. Lynford L. Goddard received the B.S. degree (with distinction) in math and physics, the M.S. degree in electrical engineering, and the Ph.D. degree in physics from Stanford University, in 1998, 2003, and 2005, respectively. His doctoral research focused on characterization and modeling of 1.5*m GaInNAsSb/GaAs lasers. At Lawrence Livermore National Lab, he conducted post-doctoral research on photonic integrated circuits, sensors, and data processing systems.

Dr. Goddard joined the University of Illinois as an assistant professor of Electrical and Computer Engineering in 2007. He was promoted to associate professor in 2013. His research group focuses on fabricating, characterizing, and modeling photonic sensors, integrated circuits, and instrumentation, as well as developing new processing techniques and testing novel semiconductor materials and devices. Applications include hydrogen detection for fuel cells, carbon dioxide detection for reducing post-harvest food loss, optical spectrum analysis and quantitative phase microscopy for metrology, and integrated microring Bragg reflectors for narrow linewidth lasers and next generation chip-scale communication systems.

Dr. Goddard is an Associate Editor of the IEEE Photonics Journal. He is the recipient of a Presidential Early Career Award for Scientists and Engineers (PECASE), nominated by the Department of Energy in 2008, and the inaugural AAAS Early Career Award for Public Engagement with Science in 2011. Dr. Goddard is an author or co-author of over 100 publications and 5 patents.