Auger alignment and low kV

Investigate behavior of auger electron optics
Clean Cu sample with piece of clean gold foil, 6 mm aperture, sloped edge, St. Steel plate

30 kV max current, tilted 30 degrees to analyzer.
SEM WD 9.3 mm

Sample SE2, zoomed out to 72x, not rotated

Energy filtered image, #3 entrance slit 2 mm diameter, 2 kV at CRR 5 gain 0.05
analyzer is to image right

1 kV gain 0.2

500 eV gain 0.4 shifted 0.7 mm 23 degrees

Edge of Au foil visible in upper left of auger image, translate sample, move foil away, no change in Auger image, helps rule out magnetization or charging of sample holder plate

400 eV gain 0.6 shifted 0.8 mm

300 eV gain 0.8 shifted 1.2 mm 14 degrees

same as above CRR 20 gain 2.0, imaging qualities degraded with more decel

200 eV gain 1.2 displaced 1.8 mm  13 degrees

above corrected (-5,-1)% deflection, (-2, -0.4) Volts

100 eV gain 1.5 same deflection as above

Counts optimized at center, (-4.2,-0.7) instead of (-5,-1), counts up ~50%

80 V CRR 5 same def

slower scan for S/N, shift x def -4,2 to -4.1 10% gain in counts, only 40 mV change. "ripples" also visible in image

slit #1 full open, gain 0.3, 80 V CRR5 

optimize counts in center -5.0, +0.4, count rate 850 kHz to 1120 kHz

Shadow of bar that opens tip transfer holder, tilt 25 degrees, 50 eV CRR 3, 3 kV max beam

Green spectrum in shadow, white spectrum with sample translated in +Y/F2 direction (toward wobble stick) 3 kV max current ~ 17 nA, tilt 25

SEM scan rotated 180 degrees so bottom is wobble stick, top is STM, left is analyzer, right is x-ray, positive tilt to left

It is absolutely clear that the tip-transfer holder bar does block low KE electrons, depending on stage position and angle.  Using the wobble stick to pull the sample slightly out of the stage (2-3 mm) lets the center region of the sample be seen by Auger

Now low KE spectra work on AuSi dewetting sample, before this failed due to stage interference.