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Ion channelling in FIB milling and SIMS measurement is a process where incident ions have correlated
the collisions with the target atoms if the incident ions enter in the direction of a low
indexed axis of a crystal, and steering of the ions, due to open channels, can result in
a range several times the maximum range in non-steering directions or in
amorphous materials.
Grain size of polycrystalline materials can be measured by FIB. The contrast mechanism of those measurements is ion channeling through different crystallographic orientations in different grains.
Table 2544. Critical angles for channeling in some crystals (the ion beam and its voltage are inserted).
Crystal |
Axial
|
Plane |
<100> |
<110> |
<111> |
(100) |
(110) |
(111) |
| Al (FCC) |
6.9° (30 kV Ga+) |
9.1° (30 kV Ga+) |
4.6° (30 kV Ga+) |
6.9° (30 kV Ga+) |
5.9° (30 kV Ga+) |
7.3° (30 kV Ga+) |
| Au |
|
|
3.6° (30 kV Ga+) |
|
|
|
| |
|
4.0° (20 kV Ga+) |
|
|
|
| |
|
4.8° (10 kV Ga+) |
|
|
|
| Si |
4.93° (30 kV Ga+) |
6.39° (30 kV Ga+) |
4.05° (30 kV Ga+) |
3.2° (30 kV Ga+) |
3.7° (30 kV Ga+) |
3.1° (30 kV Ga+) |
| Cu |
7.6° (30 kV Ga+) |
9.87° (30 kV Ga+) |
5.04° (30 kV Ga+) |
5.1° (30 kV Ga+) |
4.3° (30 kV Ga+) |
5.5° (30 kV Ga+) |
| Ni |
|
|
4.6° (30 kV Ga+) |
|
|
|
| |
|
5.1° (20 kV Ga+) |
|
|
|
| |
|
6.1° (10 kV Ga+) |
|
|
|
| Reference |
|
[1] |
|
|
|
|
[1] B. W. Kempshall, S. M. Schwarz, B. I. Prenitzer, L. A. Giannuzzi, R. B. Irwin and F. A. Stevie, Ion channeling effects on the focused ion beam milling of Cu, J. Vac. Sci. Technol. B 19(3), 749, (2001).
|
