FEI Quanta FEG 250, User'S Operation Manual, Page: 161 / 228

System Options: Optional Detectors
9-13
Settings for STEM II Detector
1. Position the desired sample grid in the field of view using the ETD.
Focus and link Z coordinate to FWD.
2. Select the Detector Settings module / Detector list box / STEM II
detector.
3. Click the Insert button to insert the detector (see above).
Bright Field imaging
1. Select the Detector Settings module / Mode list / Bright Field .
2. Adjust the contrast and brightness. An image should be visible at
low magnification.
3. Change the voltage to suit the contrast necessary through the
sample.
For example: light materials (poly-silicon or silicon oxide) may work
better with 5 - 10 kV to create contrast, whereas dense materials
(metals) may require 10 - 20 kV or higher.
4. Set the desired magnification, fine focus and correct the
astigmatism.
Dark Field imaging
1. Obtain a Bright Field image first.
2. Select the Detector Settings module / Mode list / Dark Field .
3. Adjust the contrast and brightness.
HAADF (High Angle Annular Dark Field) imaging
This mode may require higher voltage to create a suitable image as
the angle subtended to the detection diode can be wide. Choosing 2×
the value used for Brightfield is a good guide level.
1. Obtain a Bright Field image first.
2. Select the Detector Settings module / Mode list / HAADF .
HADF Partial imaging
1. Select the Detector Settings module / Mode list / HADF Partial .
You can select any combination of HAADF segments by clicking it on
detector diagram. Active segments are highlighted in yellow. HAADF
segments cannot be combined with DF or BF.
Area of active segments can be “rotated” using the arrow buttons (on
the left and right side of the detector diagram) to view orientation
contrast changes etc.
Selecting the Detector Settings module / Mode list / HADF Partial
Complementary gives the signal from complementary segments to
those selected in HADF Partial.
Note:
If the 8 segments solid-state diode is installed, the Detector Settings
module looks differently, but the detector has the same handling as
described.