The document describes the process of creating a sample for transmission electron microscopy (TEM) using a focused ion beam (FIB). Key steps include: 1) Protecting the area of interest with a platinum coating to prevent ion damage during milling. 2) Milling trenches around the area and cutting it into a rectangular sample attached by a thin section. 3) Plucking the sample from the bulk material using a probe and welding it to a TEM grid. 4) Polishing the sample to a thin, uniform thickness of around 100nm for atomic resolution TEM imaging of features like grain boundary complexions.

1. CREATING A SAMPLE FOR THE TEM
Focused Ion Beam (FIB)

2. How it works?
Reasons for one electron beam
and one ion beam
 Viewing three dimensions
 SEM provides view of x- and y-directions
 FIB provides view of y- and z-directions
 Monitoring sample fabrication with non-
destructive SEM
 Determining if the final sample is of uniform
thickness
 Brightness of sample should be consistent

3. How it works?
Eucentric height adjustments
 Sample holder is tilted back and forth
 Height (z-direction) is adjusted until the area of interest
remains centered at all tilts
 Both FIB and SEM can view the same area
Eucentric height is
typically around 5mm in
most FIBs

4. How it works?
Sample protection (Pt deposition)
 Wetting of tungsten tip to make Ga+
ions
 Injection of Pt-based metallorganic gas
 Pt is deposited and organics leave
 Pt coating protects the area of interest
from further ion damage

5. How it works?
Ion milling
 Trenches are created around the area of interest
 Milling is monitored by the SEM beam
Sample cutting
 Rectangular sample is cut so
that it is barely attached
Pt

6. How it works?
View of milled sample

7. How it works?
Sample Plucking
 Pt gas probe reinserted
 Sample plucker is inserted
 Plucker is microwelded to the
sample
 TEM sample is lifted from the bulk
material

8. How it works?
Welding to the TEM grid
 Eucentric height of grid is found
 Sample is moved against the grid
 Sample is microwelded to the grid
 Plucker is ion milled off

9. How it works?
View of mounted sample

10. How it works?
Sample polishing
 Needed for atomic resolution in TEM
 Eliminates ion impurities from milling (surface damage)
 Low current is used to prevent impurities and surface damage
 Final sample is ~100nm thick
 Final sample must have parallel surfaces and consistent
thickness
 Final sample will be bright due to electron transparency

11. What we are looking for
Grain boundary complexions

12. What we are looking for
A good high resolution TEM image of complexions