Researchers at the National Institute of Standards and Technology have adapted a low-cost optical method of examining the shape of small objects so that it can detect certain types of nanocontaminants smaller than 25 nanometers in height. The researchers originally developed the technique to record the three-dimensional shape of small objects, not to detect nanocontaminants. But by optimizing both the wavelength of the light source and the alignment of an optical microscope, the team produced images with the sensitivity required to reveal the presence of nanocontaminants in a small sample of semiconductor material.
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