Scanning Electron Microscopy and X-Ray Microanalysis

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of 6 nm and demonstrates the superior resolution that can be

attained with think samples and the TKD method.

29.2.10 Application Example

Application of EBSD To Understand Meteorite

Formation

EBSD has found application in many materials studies from

ceramics, to semiconductors to metals and alloys. It has also

has been applied to understanding metallic meteorites and

their thermal history. One example of this will be illustrated

with the Gibeon meteorite. There has been interest in

understanding the beautiful Widmanstatten pattern that is

seen in these meteorites and how this two phase structure

of ferrite (body-centered cubic crystal structure) and aus-

tenite (face-centered cubic crystal structure). Previous

work had studied the formation of this structure and most

of those studies had assumed that at high temperatures in

the parent asteroid the meteorite consisted of very large

grains of austenite. During the cooling of this meteorite in

space over many millions of years the austenite was assumed

a b

. Fig. 29.23 TKD of polycrystalline Si layers in a semiconductor device. These maps were acquired at 30 kV with a 6-nm step size. a Band quality
image of the Si layers. b Orientation map with respect to the growth direction of the polycrystalline Si layers
. Fig. 29.22 TKD patterns collected at 30 kV from a thin sample of austenite. The imaging conditions and sample thickness result in either
typical-appearing Kikuchi patterns, as shown in the left image; or if the sample is very thin, spot patterns can be collected (right)

Chapter 29 · Characterizing Crystalline Materials in the SEM