Comparison between SEM and TEM

Comparison between SEM and TEM
- Practical Electron Microscopy and Database -
- An Online Book -

http://www.globalsino.com/EM/

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Table 4997. Comparison between SEM and TEM in semiconductor applications (detailed version of this table: link).

	SEM	TEM
Typical spatial resolution	1 to 50 kV 30 Å depending on sample	50 to 300 kV, even a million volts: 0.5 Å or better. Atomic planes visible
Depth of field	Large	Very small
Advantages	Can view objects' three-dimensional surface, local and global information	Very high resolution, less electron broadening in specimen
Error sources and limitations	Sample drift, vibration; contamination, beam damage, three dimentional effect (beam projection artefacts) , noise
Error sources and limitations	Lack of sub-nanometre beam placement accuracy, more electron broadening in specimen affects the spactial resolution	Extensive specimen preparation is needed (therefore destructive), relatively small high-resolution field of view, cannot observe the surface of objects.
Field of view	50 nm to 10 mm	tens of nm to tens of µm
Sample size	Large area	Very small area
Magnification	Magnification ranges from 25x to 250,000x.	A series of electrostatic and electromagnetic lenses act on an electron beam to produce up to 50 million times magnification
Emission of secondary electrons	In backward direction only due to thick materials, all incident electrons generate secondary electrons	In forward and backward directions due to thin film, only some incident electrons generate secondary electrons

Definitions:
                e- = electron,
                GFPC = gas filled proportional counter,
                PMT = photomultiplier tube ,
                SCD = semiconductor detector (Si or Ge).

Furthermore, the comparison between the EDS measurements in low-energy SEM and high-energy (S)TEM is listed on a table on page4532.

[1] McMullan, D., "SEM-Past, Present and Future," Journal of Microscopy, Vol. 155, No. 3, 1989, pp. 373-392.
[2] Both SEM and TEM are useful in biology and geology, as well as in materials science.
Bibliography:
1) Goldstein, Newbury, Echlin, Joy, Fiori & Lifshin; Scanning Electron Microscopy and X-Ray Microanalysis, Plenum, 1984
2) Hirsch, Howie, Nicholson, Pashley & Whelan, Electron Microscopy of Thin Crystals, Krieger, 1977
3) ASM, Metals Handbook, 9th Edition, vol. 9, p. 89-122, Scanning Electron Microscopy and Transmission Electron Microscopy.
4) ASM, Metals Handbook, 9th Edition, vol. 10, p. 427-546, Electron Optical Methods.
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