Gun off for thanksgiving

• Extractor 5.02 kV current 107.2 uA fil 2.33 A 15 Nov 12
• Gun vac 2.72 e-10 system 1.2e-10 before gun off
• Gun vac drops slightly to 2.27 e-10 while gun runs down 

before restart on Mon 26 Oct 12

• Gun vac 1.1e-10, system 1.3e-10, gun vac fluctuates near zero
• have "column pumping" = pumping, "ready", occasionally off, EHT vac ready = no
• Throttle ion pump, open Ar leak valve to get system pressure 1e-8, try to get SEM ion pressure stable above 1e-10. Not enough, pressure (ion pump current monitor) fluctuates below 1e-10
• Have to open pump bypass, get ion pump pressure ~ 3 e-10 with no fluctuations below 1e-10, after ~ 100 sec stable pressure, EHT vac goes to ready, now start gun run up

Extractor reaches 5020 V at 9:50

9:50  78.4 uA

9:53  83.4

9.56  85.2  also close bypass, gun vac 8.8e-11

10:13  92.3

11:48 105.6 close to steady state

On Tuesday, gun 107.8 uA EHT off, 62 uA EHT on 3 kV, 42.5% extraction

Toolbar Customize

Added two new toolbar buttons.

• rightmost multi-image sets slow speed, restarts scan, freeze at end, save both channels, or only one if not dual mode, restarts scan faster speed. Current speed 12
• +/- icon on right steps up or down mag in 1/2/5/10 steps between 100 x and 100 kx
• macros can call exe programs, could be used to sync Auger with other pc...

Image tests

Auger Image Test

Si wafer plus oxide

Take auger spectra, zoom into 200x image region, left if image oxidized, right not oxidized.

Verify ImageJ can read 16 bit images, adjust contrast 0.16 DAC1 for CRR5 at 507

Image 9, 10 sequential 507 images, can check for noise

Image 11 is 523, image 12 is 533, 13 is InLens

Change to scan speed 14 512x384 image, 0.8 us/pixel, 2.8 min, record 507
Next 523 then 533.
Auger counts ~ 1 MHz, so 800 cts/pixel, SNR ~ 28

Take spectra at 50, 10, 2, 1 ms point to evaluate SNR, 1 ms is minimum interval, actual elapsed time >> than apparent time.

Processing

ImageJ reads images, can calculate differences, as float data to handle negatives. Reasonable Auger image of O KLL on Si.

• Calibrate Zeiss inputs. Image grey_test_02.tif is 16 bit, start at 1.0 V, descend in -.1 volt steps to 0, again 1.0, then -0.1
• 1 volt region is 4965 counts of 20724, 1756 of 20720.  No 21, 22 or 23. Must be 14 bit A/D
• 0 V is 1784 +/- 4
• if linear, 18.94 k/V. 0.21 mV/bit (14 bit) or 52.8 uV/bit (16 bit)
• min is -.094 V, max is 3.36 V
• 0.1 3582
• 0.2 5564 but spread over ~ 10 values
• .3 7240
• .4 9338
• .5 11258
• .6 13048
• .7  15032
• .8  16886
• .9 18846
• 3.0 V is 58386, 89.1%
• 0 is 1778, 2.7%
• 3.1 is 60278, 3.2 is 62168, 3.3 63976, 3.35 64988

Ion Gun Problems

• Ion gun controller has always had relays clicking, anywhere from every hour or so to every minute or so. Ion current drops momentarily to zero on click
• Today (11/8/12) got essentially no ion current at 2 kV, same settings that were good last week
• sample current monitor ~ 1-2 nA, should be 100's
• no SE detected by hemisphere
• changing offset, obj, cond no help
• pressure sensor DID change with gun standby/sputter
• At 2500 V did get sample current ~ 200 nA. 
• Got SE signal earlier in the afternoon, later no signal.
• Shutdown gun and software, restart, no change.

Fixed

• My bad. When rerouting cables, J8 float voltage was attached to transition lens SHV connector. Therefore gun was floating and operating in a weird mode.
• After fixing cable, 3.6 uA by SCM, also lots of counts.
• Relay clicking, current dropping issue still exists.

Dewetting experiments continued

directory 121108 SiAu

Si reference

• Take SiO sputter sample to get Si reference. Look near region sputtered last week.
• Get Inlens detector working. At 3 kV, very bright region is SiO, darker regions SiC. No clean Si seen
• Sputter sample 2 kV 3x3 raster 20 mPa cond 66 obj 61 grid 150 30 degree tilt

Problem - sputter issues, sample current does not change much, no SE in Auger.

• almost no SE signal
• sample current 2 nA for 2 kV ions. Change to 2.5 kV, now 260 nA, reasonable SE signal 250 kHz CRR 5 at 80 eV
• 2500 V does give reasonable sputter rate. Remove C and O with ~ 150 sec sputter
• also discover software for FIG5 has timer for sputter...

Take reference spectra 121108 SiAu.aes, Si LVV and KLL regions at 3 kV and 10 kV.

• Si KLL ~ 1% peak for 3 kV, ~ 40% for 10 kV. Spectra in CRR and CAE
• Good quality Si data

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.

Auger Problem Deflection

Several problems

• absolute count rate drops
• low KE auger really bad
• Octopole does not have normal effect on counts
• low mag image of #3 aperture offset
• switch back to Cu110 sample, not normal

Deflection voltages

• Xa+ is bad, stuck at -5.5 V from 20 to 100% (load or no load). 10% -1.16, 5% -0.3, 0% +6.8
• Xa- tracks, opposite of Xa+
• Ya+, 0% -1, 10% -.8, 20% to 100% -.4
• Ya- tracks Ya+
• B X&Y stuck at zero independent of control settings.

Ground all 8 electrodes to 'system ground'

Cu110 CRR5 3 kV max, low KE distorted

More or less normal spectra at high KV

Good Cu110 spectrum recorded when quadrupole worked, 30 tilt

Now try to cycle power on PC and EAC

While power is off, remove and physically inspect EAC deflection boards. No visible damage. These seem pure analog, GPIB decode and voltage generation elsewhere? +/- pairs seem to be on deflection boards (op amp circuits)

• Before EIS starts, voltage (disconnected from analyzer) at -40 V on XA+
• Voltages different from before but still bad, should be -40 to + 40 V for 0-100%
• Xa+  0% 7.2, 10% -7.2, 20% and above -15.9; Xa- is opposite
• Ya+ 0% 0 10% -.8, 20% and above -0.4; Ya- tracks
• XY b zero always

Now try ISEM. Do EA SEM image manual deflection, X and Y 25%, values go to -20.0 V for Xa+, Ya+. What does this mean?

Now EIS Octopole control works!!!

Optimize at 80 V, spectrum normal above 135, drops off quickly below that. Nothing below 60 V. Better but still different from before.

residual B field from lens after higher KV operation???

Something charging near sample???

Better with octopole, but problems below 135 eV

EAC Control

Build Labview routine to control EAC instead of EIS.

• mult on off
• CAE/CRR and Epass
• KE, span and fraction
• quadrupoles

EIS quits if LV cable disconnected and GPIB write fails - no error handling

Changes needed to FPGA:

1. remove DAC1 mode, not supported?
2. Decimate should have a separate Delta T routine, 32 bits, call once per transfer cycle, no need to slice into 10 us intervals then sum back to 10 ms...

Changes to PC GUI

1. Add gpib controls
2. add noise calculation
3. decimate by summation

ISEM DMA acquisition problems

ISEM DMA modes do not work. Image acquisition otherwise hopelessly slow.

• verify Hsync, Vsync, Pixel clock outputs from Zeiss PC, these look good.
• Pull multichannel receiver out of rack, verify signals arrive on board, they do.\
• Shut down PC and reseat PCI cards (Zeiss control and Omicron data acq)
• this was suggested as a possible fix for detector contrast problem
• Now try ISEM DMA
• now it works. no obvious problem fixed???
• put back in rack, still works

ISEM tests

• image acq will be painfully slow. Test with spectra at, for example, 1 ms acq time. cannot see Si KLL on Si, for example
• with CRR 3 and 25 ms/pixel, can start to see spectra (10 kV max current)
• with 200 ms, not bad
• image time line by line ~ 2-3x raw image time (zeiss) for fast scans, overhead may reduce
• optimal image (no OH) at 0.2 sec, for 2x512x384, around 20 hours...
• there is a line scan mode, can do point by point or line by line, but cannot get line data, only peak/back. No chance for own processing.
• for Au on Si, large backscatter and noise effects, swamps real contrast

To try

• can take reduced image for test
• can modify data 'schema' to get access to raw images peak/back acquired line by line, for post process later
• can try multipoint acq to get family of spectra, but OH and data format may be a pain.
• need to test data export, image dynamic range may be reduced either to 256 or 100 values (bad)

SiAu Expt continued

Take nice high res spectra Si KLL and Au MNN regions

Si peak structure in eutectic regions quite modified.


Au film far (~ 100 um) from dewet area shows no Si

Near edge clear Si. Also in squares and dewet droplets, more in the latter case. Suggestion droplets less Si than squares..

Compare Au film far from DZ and at edge of DZ

Compare Au film far from DZ and at edge of DZ

Si region for DZ and eutectic

Si region for DZ and eutectic

X-ray Levels of Elements

info from CRXO.lbl.gov x-ray data base

Carbon (C ) Z = 6

• Atomic Weight : 12.011
• Density : 2.20 g/cm^3

  K1     284.2 (ref.2)

Oxygen (O ) Z = 8

• Atomic Weight : 15.999
• Density : 0.143E-02 g/cm^3

  L1      41.6 (ref.2)
  K1     543.1 (ref.2)

Silicon (Si) Z = 14

• Atomic Weight : 28.086
• Density : 2.33 g/cm^3

  L3      99.8 (ref.4)
  L2     100.4 (ref.4)
  L1     149.7 (ref.2)
  K1    1838.9 (ref.1) 

K-related Auger peaks

1540

1551

1557

1576

1582

1598

1609

1617 strongest

Electron Level Widths (eV)

  L3     0.014
  L2     0.015
  L1     1.030
  K      0.480

Vanadium (V ) Z = 23

• Atomic Weight : 50.942
• Density : 6.11 g/cm^3

  M3      37.2 (ref.3)
  M2      37.2 (ref.3)
  M1      66.3 (ref.3)
  L3     512.1 (ref.3)
  L2     519.8 (ref.3)
  L1     626.7 (ref.3)
  K1    5463.8 (ref.5) 

Electron Level Widths (eV)

  L3     0.240
  L2     0.260
  L1     2.410
  K      1.010

Copper (Cu) Z = 29

• Atomic Weight : 63.546
• Density : 8.96 g/cm^3

  M3      75.1 (ref.3)
  M2      77.3 (ref.3)
  M1     122.5 (ref.3)
  L3     932.5 (ref.3)
  L2     952.3 (ref.3)
  L1    1096.7 (ref.3)
  K1    8980.5 (ref.5) 

Electron Level Widths (eV)

  L3     0.560
  L2     0.620
  L1     3.060
  K      1.550 

Gold (Au) Z = 79

• Atomic Weight : 196.967
• Density : 19.3 g/cm^3

  O3      57.2 (ref.3)
  O2      74.2 (ref.3)
  O1     107.2 (ref.3)
  N7      83.9 (ref.3)
  N6      87.6 (ref.3)
  N5     335.1 (ref.3)
  N4     353.2 (ref.3)
  N3     546.3 (ref.3)
  N2     642.7 (ref.3)
  N1     762.1 (ref.3)
  M5    2205.7 (ref.1)
  M4    2291.1 (ref.1)
  M3    2743.0 (ref.1)
  M2    3147.8 (ref.1)
  M1    3424.9 (ref.1)
  L3   11919.7 (ref.5)
  L2   13734.2 (ref.5)
  L1   14355.3 (ref.5)
  K1   80724.9 (ref.1)

M4,5 related Auger peaks

observed 10 kV CRR 10 and CAE 200 Omicron Auger up to 2200 eV

1499

1518

1588

1651 weak

1743

1765

1828

1858

1929

1992

2016 strongest

2022

2072

2101 strong

Electron Level Widths (eV)

  L3     5.410
  L2     6.000
  L1    10.500
  K     52.000
 

SiAu dewetting expt

Play around with conditions. Si and Au LMM peaks much better for 8 kV than 3 kV. % is OK but 8 is better. Did not try above yet. Peak stronger background less.

At 8 kV hard to get signal below ~ 250 eV regardless of deflection settings.
For 8 kV 1600 V approx +36.7,51.5 octopole

On eutectic squares and blobs, AuSi silicon peak is dramatically changed in shape
Doublet 1616.5, 1609 and 1557.5, 1552.5

Pure Si more like 1617, 1598, 1577, 1559, 1543

Au core levels
4s 763
4p  643, 547
4d 353, 335
5s ~ 110
4f 84, 88
5p 57, 74