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John S. Villarrubia (Fed)

John Villarrubia is a physicist and project leader in the Microsystems and Nanotechnology Division of the Physical Measurement Laboratory (PML) at the National Institute of Standards and Technology (NIST). He received a B.S. in Physics from Louisiana State University and a M.S. and Ph.D. in Physics from Cornell University. At Cornell he helped to build the first time-resolved high-resolution electron energy loss spectrometer for measuring surface-molecular vibrational excitations. At IBM as a postdoc, he did early scanning tunneling microscopy work that produced atomic-resolution images of Cl-modified Si surfaces, work published in Physical Review Letters and Science. At NIST he contributed to the Molecular Measuring Machine project, applied mathematical morphological methods to the tip-sample interaction in an STM or AFM to invent the first blind reconstruction method for determination of tip geometry (with over 400 citations at this writing the 4th most heavily cited paper in J. Res. NIST), and developed JMONSEL, a Monte Carlo simulator that uses a suite of physics models for electron-solid interactions to simulate secondary electron image formation for 3-dimensional samples of arbitrary shape. He is a fellow of the Washington Academy of Sciences, recipient of three Nyyssonen Metrology best paper awards, a Nanotech Briefs Nano50 Technology Award, and Dept. of Commerce Silver and Gold medals.

Selected Publications

Unbiased Estimation of Linewidth Roughness

John S. Villarrubia, B Bunday
Line width roughness (LWR) is usually estimated simply as three standard deviations of the line width. The effect of image noise upon this metric includes a

Scanning Electron Microscope Analog of Scatterometry

John S. Villarrubia, Andras Vladar, J R. Lowney, Michael T. Postek
Optical scatterometry has attracted a great deal of interest for linewidth measurement due to its high repeatability and capability of measuring sidewall shape


Model Validation for Scanning Electron Microscopy

Olga Ridzel, Wataru Yamane, Ishiaka Mansaray, John S. Villarrubia
We are beginning projects to validate the physics models used for interpretation of electron microscopy images. In one, we will measure electron yields and

Probing Electrified Liquid-Solid Interfaces with Scanning Electron Microscopy

Hongxuan Guo, Alexander Yulaev, Evgheni Strelcov, Alexander Tselev, Christopher M. Arble, Andras Vladar, John S. Villarrubia, Andrei Kolmakov
The mean free path of secondary electrons in aqueous solutions is on the order of a nanometer, making them a suitable probe of ultrathin electrical double
Created October 9, 2019, Updated December 8, 2022