Does your SEM really tell the truth? How would you know? Part 2

Abstract

The scanning electron microscope (SEM) has gone through a tremendous evolution to become indispensable for many and diverse scientific and industrial applications. The improvements have significantly enriched and augmented the overall SEM performance and have made the instrument far easier to operate. But, the ease of operation also might lead, through operator complacency, to poor results. In addition, the user friendliness has seemingly reduced the need for thorough operator training for using these complex instruments. One might then conclude that the SEM is just a very expensive digital camera or another peripheral device for a computer. Hence, a person using the instrument may be lulled into thinking that all of the potential pitfalls have been eliminated and they believe everything they see on the micrograph is always correct. But, this may not be the case. An earlier paper (Part 1), discussed some of the potential issues related to signal generation in the SEM, instrument calibration, electron beam interactions and the need for physics-based modeling to understand the actual image formation mechanisms. All these were summed together in a discussion of how these issues effect measurements made with the instrument. This second paper discusses another major issue confronting the microscopist: electron-beam-induced specimen contamination. Over the years, NIST has done a great deal of research into the issue of sample contamination and its removal and elimination and some of this work is reviewed and discussed here.

Documentation for Reference Material (RM) 8820 : A Versatile, Multipurpose Dimensional Metrology Calibration Standard for Scanned Particle Beam, Scanned Probe and Optical Microscopy

“…It is possible to achieve essentially contamination-free SEM operation [10][11][12][13]. Regular monitoring of the contamination performance of the SEM is critical.…”

Does your SEM really tell the truth? How would you know? part 3: vibration and drift

“…Two earlier papers (1,2), discussed some of the potential issues related to signal generation in the SEM, instrument calibration, electron beam interactions, and the need for modelling to understand the actual image generation. All these were summed together in a discussion of how these issues effect measurements made with the instrument.…”

“…1 Contribution of the National Institute of Standards and Technology, not subject to copyright. 2 Certain commercial equipment is identifi ed in this report to adequately describe the experimental procedure. Such identifi cation does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the equipment identifi ed is necessarily the best available for the purpose.…”

Nanomanufacturing concerns about measurements made in the SEM Part III: vibration and drift

“…This third paper, discusses the additional components of measurement uncertainty 1 Contribution of the National Institute of Standards and Technology, not subject to copyright. 2 Certain commercial equipment is identifi ed in this report to adequately describe the experimental procedure. Such identifi cation does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the equipment identifi ed is necessarily the best available for the purpose.…”