Tool bar and button bar (Many SEM functions are mouse ：工具条和按钮栏（许多扫描功能的鼠标.ppt

Tool bar and button bar (Many SEM functions are mouse ：工具条和按钮栏（许多扫描功能的鼠标
To insert your sample
Check that high volta spot size = 4, 15 kV
Link
Initially your stage should be about 13 mm down if you have not raised it to the 10 mm mark..but could be anywhere: it has no way of knowing where you mounted the top of your sample!
Focus
Increase magnification
Focus
Link
Z-coordinate is now correct
Less crucial if using only samples of minimal thickness
Absolutely crucial for samples of widely varying thickness
Extremely crucial if sample is taller than elephant nose!
Image optimization
With Everhart-Thornley or Low Vac Detector, raise stage to about 5 mm
Typically during pump-down with roller ball
With cursor low on screen, press roller ball and roll mouse up
Watch active (not paused!) image of sample mount on CCD
Translation speed is proportional to distance cursor is from starting point
“"When I Use a Word, It Means Precisely What I Want It To Mean....“ Humpty Dumpty
In the lexicon of Leo, “Beam current” is the current leaving the filament and “Probe current” is an approximation to the current incident on the sample, usually high by about a factor of two.
From FEI, “Beam current” is an excellent approximation to the current actually striking the sample.
Low vacuum
Why?
Polystyrene ballsHigh vacuum, 16 kX
Polystyrene ballsHigh vacuum, 100 kX
Polystyrene ballsLow vacuum, 16 kX
Polystyrene ballsLow vacuum, 100 kX
LVD.
Helix detector in
immersion mode
will improve
image by
approximately
one order of
magnitude!
Low vacuum
Why?
For non-conducting samples
To avoid rapid deposition of crud on your sample.
ETD does not work
New detector must be installed…while wearing gloves
LVD is relatively cheap and adequate for images up to about 50 kX
Helix is very expensive but gives killer images on non-conducting samples to 500 kX or more!
PLA must be installed sufficiently tightly that it does not leak and kill the column
“WD” must be redefined if a PLA