494
29
29.1.2 Polycrystalline Materials
Most crystalline materials are not single crystals. During
solidification from a molten state, numerous crystals
nucleate randomly in the liquid and grow in size until they
encounter each other, producing a three-dimensional
microstructure of randomly oriented crystalline units
called “grains.” Materials fabrication processes such as
5°
[001]
5° 5 mm 5 mm
(220)
(110)
(400)
(100)
ab
. Fig. 29.3 a Wide field scanning (BSE image) of a Si single crystal
wafer whose surface is parallel to the (001) plane, thus looking along
the [001] pole; E 0 = 15 keV. b The traces of two different sets of crystal
planes are marked, as well as the parallel channeling bands defined
when the scan angle to the planes equals ± θB. Images processed with
ImageJ-Fiji CLAHE function
2° 1 mm 1° 500 μm
ab
. Fig. 29.4 a, b Progressively smaller scanning areas (higher magnifications) restrict the angular range and thus the portion of the electron
channeling pattern that is observed. Images processed with ImageJ-Fiji CLAHE function
Chapter 29 · Characterizing Crystalline Materials in the SEM