1. Microscopia de Iones y Nano-Tecnología Eduardo H. Montoya Rossi

2. 1 The Focused Ion Beam (FIB) Instrument.

3. 2 The FIB column.

4. 3 How the FIB works.

5. 4

6. 5 What is it possible with FIB? Micromachining.

7. 6 What is it possible with FIB? FIB tomography.

8. 7 What is it possible with FIB? Material deposition.

9. 8 What is it possible with FIB? TEM sample preparation.

10. 9 Sample preparation is a critical step in Transmission Electron Microscopy (TEM) studies.

11. 10 Conventional techniques have been used for long time.

12. 11 New, state of the art, transmission electron microscopes require ultra high quality samples, “free from any surface damage and with negligible surface roughness” (Genç et al. Microscopy & Microanalysis, 13:1520-1521, 2007).

13. 12 Constant thickness is required for quantitative transmission electron microscopy (TEM) methods.

14. 13 FIB preparation of a TEM specimen: A thick lamella is machined by focused ion beam milling. Then extracted (lift out) by a needle. Bulk sample surface

15. 14 FIB preparation of a TEM specimen: The specimen is welded to a TEM grid and released from the needle. Then thinned by low current and low energy FIB milling. The result is a (high quality?) TEM lamella. BF - TEM

16. 15 FIB – TEM on mono-crystalline Ge Difficult case Top: S. Rubanov & P.R. Munroe. Micron, 35:549 – 556 (2004) Bottom: present work. HRTEM HAADF-STEM Finished at 5 keV Finished at 10 keV

17. 16 S. Bals, unpublished Ion milling – HRTEM on LAO / STO multilayer LAO STO

18. 17 LAO / STO multilayer: HRTEM FIB LAO STO

19. 18 Double cross sectional study: Examining the cross section of the cross section. Provides direct measurement of the thickness of a FIB prepared TEM specimen. Provides information about the thickness, origin, structure and composition of the damaged / amorphous layers induced by the FIB preparation process. Why is it important?

20. 19 Double cross section technique 1.Cover both sides of the specimen with sputtered Au. 2.Embed the Au-covered specimen in a Pt brick. 3.Cut slices from the Pt brick. Grid horizontally mounted 1 2 2 1 1,2: observation directions

21. 20 Proposed procedure is clean, easy, fast and reliable

22. 21 Double cross sectional study: LAO / STO HAADF-STEM Specimen thickness is fairly constant inside the Region of Interest (ROI). Bottle like shape of the cross section.

23. 22 ROI: HAADF-STEM image (A) and EFTEM maps of Ti, La and Ga (B, C). Spreading of La (B) and enrichment of Ga (C) in amorphous layers. Boxes indicate regions selected for intensity scan plots (next slide). Double cross sectional study: LAO / STO FIB Au HAADF-STEM EFTEM

24. 23 Question marks (A): La and Ti signals not detected by HAADF- STEM. These signals correspond to redeposited amorphous material. Peaks of La at borders of original specimen cross-section (B). Intensity scan plots across (A) and along the multilayer (B). Double cross sectional study: LAO / STO