1. Applications of high resolution XPS & AES
Kratos AXIS UltraDLD
The small spot, parallel imaging,
multi-technique photoelectron spectrometer
Dr Chris Blomfield

2. Kratos Analytical Ltd Kratos headquarters Manchester UK
service/sales centres
New York, Tokyo,
Singapore, Frankfurt

3. Home of Manchester United
Kratos
Old Trafford Football
Home of Manchester United
Old Trafford Cricket
Home of LCCC

4. All featuring common Axis technology Virtual probe Magnetic lens
1969
ES-100
ES-200
ES-300
XSAM series HS
1984
2004
AXIS Nova
AXIS UltraDLD
2003
AXIS Ultra
1997
AXIS 165
1994
AXIS HSi
1991
ES-100 launched 1969
XSAM series
Axis series launched 1995
Axis HS 3 detectors 35
Axsi HSi 5 detectors 40
Axis detectors 45
Axis Ultra imaging 195
Axis Nova 40
Total units 355
All featuring common Axis technology
Virtual probe
Magnetic lens
Coaxial charge neutraliser
Spectral resolution and sensitivity

5. What is the surface?
What happens at surfaces is extremely important in a vast range of applications from environmental corrosion to medical implants.
A surface can be thought of as the interface between different phases (solid, liquid or gas).
We can think of the surface as the top layer of atoms but in reality the state of this layer is very much influenced by the 2 – 10 atomic layers below it (~0.5 – 3 nm).
Surface modification treatments are often in the range of 10 – 100 nm thick. >100 nm can be thought of as the bulk.
Surface analysis encompasses techniques which probe the properties in all these ranges.

6. Surface Analysis - Techniques Available
Properties and reactivity of the surface will depend on:
bonding geometry of molecules to the surface
physical topography
chemical composition
chemical structure
atomic structure
electronic state
No one technique can provide all these
pieces of information. However, to
solve a specific problem it is seldom
necessary to use every technique
available.
photons
ions
electrons
EMISSION
TRANSMISSION
Interaction
with material
EXCITATION

7. Surface Analysis - Techniques Available
Analytical Technique Signal Measured Elemental Range Depth Resolution Surface info.
SIMS Secondary Ions H-U Å Chemical composition
(secondary ion mass spectrometry) Chemical structure
TOF-SIMS Secondary Ions H-U, Large Organic Å (Scanning Mode) Adsorbate bonding
(time-of-flight SIMS) Molecules / Cluster Ions
TEM Transmitted Electrons X-Rays Na-U EDX N/A
(transmission electron microscopy)
FE-SEM, EDX Backscattered or Na-U micrometres
(field emission SEM) Secondary Electrons and X-Rays
ISS Ions H- U monolayer atomic structure
(ion scattering spectroscopy) chemical composition
AES/SAM Auger Electrons Li-U nm chemical composition
(Auger electron spectroscopy, scanning Auger microscopy)
ESCA/XPS Photoelectrons Li-U 1 – 10 nm chemical composition
(electron spectroscopy for chemical analysis, X-ray photoelectron spectroscopy) chemical structure
RAIRS IR photons organic, some inorganics monolayer Adsorbate bonding
(reflection-absorption infra-red spectroscopy)
STM - solid surfaces upper most atoms physical topography
(scanning tunnelling microscopy)
Analytical Technique Signal Measured Elemental Range Depth Resolution Surface info,

8. Surface Analysis - Techniques Available

9. Surface Sensitivity of XPS
Penetration depth of the X-ray radiation is nm.
However, the surface sensitivity of XPS arises from the short distance the photoelectrons can travel in the solid before suffering inelastic scattering.
The average distance from the surface a photoelectron can travel without energy loss is defined as the inelastic mean free pathlength (IMFP), λ.
Sampling depth, d, defined as the average distance from the surface for which 95% of photoelectrons are detected, d = 3λ. d
Photoelectrons out
X-rays in
d = 3λ

10. What information do we get from XPS?
Surface sensitivity - photoelectron signal from first 1-10 layers of atoms and molecules.
Identification of all elements (except H & He) at concentrations >0.1atomic%*.
Quantitative determination of the elemental composition.
Information about the chemical state (molecular environment) of the element.
Non-destructive analysis, including depth profiles, from the top 10 nm.
Destructive depth profiles of inorganic materials for 100s of nm.
Lateral variations in surface composition at >3µm resolution.
‘Finger printing’ of materials using valance band.
*Sensitivity - a sample with a surface of size 1 cm2 - this will have ca atoms in the surface layer. In order to detect the presence of impurity atoms present at the 1% level, a technique must be sensitive to ca atoms. Contrast this with a spectroscopic technique used to analyse a 1 cm3 bulk liquid sample i.e. a sample of ca molecules. The detection of 1013 molecules in this sample would require 1 ppb (one part-per-billion) sensitivity - very few techniques can provide anything like this level of sensitivity.

11. The X-ray Photoelectron Spectroscopy Experiment
Prof. Kai Siegbahn, Uppsala University, pioneered the technique of XPS, producing the first well defined spectrum in 1954 & was awarded a Noble prize for his work in 1981.
Since then the basic building blocks of the X-ray photoelectron spectrometer have not changed.
However, UHV technology and electronics have improved!
X-ray source
UHV analysis
chamber
Electron energy analyser
Electron detector
sample

12. The Photoelectron Spectrum – Surveys/Wide Scans Which elements are present and how much have we got?
O 1s
O KLL Auger
C 1s
Cu LMM
Auger
Cu 2p
The energy of the photoelectron peak is indicative of the element from which it originated.
The number of electrons (peak area) is related to the elemental concentration.
Both photoemission and Auger peaks observed in a spectrum.
Peaks are superimposed on a rising background, due to inelastically scattered photoelectrons.
N 1s
Cl 2s
Cl 2p
Cu 3s
Cu 3p

13. The Photoelectron Spectrum – High Resolution What chemical state are the elements in?
O 1s
C 1s
O KLL
Auger
O 1s
C 1s
High resolution spectra show the subtle shifts
in energy of photoelectrons originating form
different chemical environments.

14. Chemical State Information
The binding energy of an electron is dependent on the atomic orbital the electron occupies and the chemical environment of the atom.
The variation of binding energy of a specific photoemission peak provides information on the chemical state of the atom or ion.
Valence electron, low binding energy
Core level electron, high binding energy

15. Chemical State Information
Typical binding energies for C 1s photoemission peaks from organic materials
functional group binding energy (eV)
hydrocarbon C-H, C-C
amine C-N
alcohol, ether C-O-H, C-O-C 286.5
fluorocarbon C-F
carbonyl C=O
2F bound to a carbon -CH2CF
3F bound to a carbon -CF
Typical chemical shifts for O 1s photoemission peaks from organic materials
carbonyl -C=O, O-C=O 532.2
alcohol, ether -O-H, O-C-O 532.8
ester C-O-C=O

16. Quantitative Surface Analysis of Poly(ethylene tetraphthalate) - PET Large Area Survey
Peak Position FWHM Raw Area RSF Atomic Atomic Mass
BE (eV) (eV) (CPS) Mass Conc % Conc %
C 1s
O 1s
O KLL

17. Quantitative Surface Analysis of Poly(ethylene tetraphthalate) - PET Chemical State Information
-(-O-C C-O-CH2-CH2-)- = O n 2 3 1
C 1s region C1 O2 O1
O 1s region
O(1) 530.8eV 49 at%
O(2) 532.1eV 53 at%
C(1) 285.0eV 61 at%
C(2) 286.5eV 21 at%
C(3) 289.2eV 18 at% C3 C2

18. Monochromated vs non-monochromated X-ray source
Monochromated Al Kα excited Ag spectrum
Ag 3d
Ag 3d5/2
Ag 3d3/2
Ag 3p3/2
FWHM 0.46 eV
Ag 3p1/2
Ag 3s
Non-monochromated Mg Kα excited Ag spectrum
Ag 3d5/2
Ag MNV Auger
Ag 3d
Ag 3d3/2
FWHM 0.97 eV
Ag 3p3/2
Ag 3p1/2
Ag 3s
satellite
satellite
Things to note: loss of rising background, narrower peaks, loss of satellite peaks, movement of Auger peaks

19. Beyond Large Area Spectroscopy
<10 nm
thin film
thicker layer or multilayers
heterogeneous surface
angle resolved XPS
depth profile
parallel imaging
selected area spectroscopy

20. AXIS UltraDLD 240 instruments installed Unique DLD detector technology
128 channel snap shot
3um parallel imaging
15um small spot
Research grade performance
energy resolution < 0.45eV
sensitivity and therefore detection limits
Flexible multi-technique configuration
XPS, UPS, AES, ISS
Large selection of sample preparation

21. Axis Ultra performance
80eV
40eV
20eV
10eV
5eV

22. Instrument overview 1 Al monochromatic source1. 2. 3. 4. 5. 6. 8. 7.
1 Al monochromatic source
2 Mg/Al achromatic source
3 Low energy floating ion gun
4 165mm radius HSA & SMA
5 Transfer lens & aperture/iris
6 TMP 250 l/s for STC
Options
7 10 kV Field emission source
8 UPS lamp

23. Configuration 1. 2. 3. 4. 6. 5. 7. 8. 9. 1 Al monochromatic source
2 Mg/Al achromatic source
3 Low energy floating ion gun
4 CCTV camera port (not shown)
5 Magnetic lens
6 Ion pump offset from SAC
7 TMP 250 l/s for STC
Options
8 10 kV Field emission source
9 UPS lamp

24. Si 2p Spectrum – pass energy 5 eV
Peak height 5403 cps
Peak fitted spectrum
Si 2p3/2
Si 2p1/2
FWHM Si 2p3/2
0.367 eV
oxides
Native oxide

25. Ag Fermi edge - RT – pass energy 5 eV
Ag EF < 250meV
Large area (700 x 300 microns) Ag 3d5/2 Fermi Edge spectrum recorded at 5 eV pass energy and 600 W X-ray power.
16% - 84% Edge resolution = eV

26. Ag 3d5/2 – pass energy 5 eV Ag 3d5/2 peak resolution
(FWHM) = eV, ~250KCPS

27. High sensitivity means high detection limits or fast analysis time

28. Typical high sensitivity available
Improved detection limits <0.05% allow analysis of low concentrations of elements
Al-Zn-In anodes are used to protect marine steel structures from corrosion.
study with XPS of the active In element
reveals surface segregation to a maximum of 4% over 1 year exposure

29. Low concentration In 3d quantification
In 3d3/2 used for quantification
Overlap with Ca 2s

30. XPS shows surface concentration of In during corrosion
Cut anode surface used to represent bulk
XPS In 0.02wt%
GDOES In wt%
As cast anode surface ~1wt% In
Corrosion tests show an increase to 4wt% over 1 year simulated corrosion

31. Analysis of insulators

32. Origin of Charge Neutralisation Electrons
Magnetic Lens Pole Piece
(2) Charge balance plate
(-ve potential)
(1) Filament
(3) Low Energy Electron
Trajectory in the Magnetic Field
Sample
1) Electrons are thermionically emitted from the charge neutraliser filament.
2) Negative potential of the charge balance plate forces the charge neutralisation electrons towards the sample. There is no direct line of sight of the filament with the sample.
3) The low energy electrons are confined by the magnetic field of the magnetic immersion lens, following an oscillating path between sample and charge balance plate.
4) As sample develops a positive charge, charge neutralisation electrons are attracted to the surface.

33. Neutralisation of Rough Samples
200 microns
800 microns
C 1s spectrum from wood fibres
The sample of wood pulp fibres shown in the optical image to the right would traditionally be an extremely difficult sample to charge neutralise. However, as demonstrated by the excellent resolution on the C 1s spectrum poses no problem with the AXIS co-axial charge neutraliser.

34. Charge Neutralization
Fully automatic system standard parameter for 99% of samples
Simple software electron only source
No Ar* ions
Works on topographic samples
There are only three parameters to define for the charge neutralisation system.
Normal user operation of neutraliser

35. Neutralization of Rough Samples
Kratos neutralisation system
- electrons following a spiral path
Collimated electrons or ions from a low energy electron/ion source + + + + + + + + + + + +
rough sample surface
For a rough sample, parts of the surface may be shadowed from neutralisation electrons originating from a collimated electron gun so that the sample will only be partially neutralised. This is overcome by the Kratos charge neutralisation system, where the low energy electrons reach the sample from all directions as a result of their spiral trajectory

36. Neutralization of Insulating samples
XPS performance on insulators for the UltraHSA is guaranteed by specification defined using a polymer. The standard used is PET (polyethylene terephthalate) which has the chemical structure shown. The specifications are defined as the cps from the CC,CH component at 285eV and the FWHM of the ester component ( C-C(=O)-O- ) at ca.289 eV.
Sensitivity of CC,CH component (cps)
FWHM of ester peak (eV)
resn
700x300um
110um
0.68eV
16,000
2,500
1.0eV
135,000
12,000
1.3eV
200,000
20,000
area

37. PET performance data

38. Effect of PE on measured data
Clear loss of chemical resolution
evidenced in carbonyl peak
10 eV PE FWHM = 0.68eV
40eV PE FWHM = 0.83 eV

39. Neutralization of Rough Samples
200 microns
800 microns
C 1s spectrum from wood fibres
The sample of wood pulp fibres shown in the optical image to the right would traditionally be an extremely difficult sample to charge neutralize. However, as demonstrated by the excellent resolution on the C 1s spectrum poses no problem with the AXIS co-axial charge neutralizer.

40. XPS Analysis of Plasma Deposited Coatings
Survey spectrum of plasma treated nylon confirming a large amount of surface F incorporation. Quantification of the XPS spectra gave 55% Fluorine on the surface.
A high resolution C 1s spectrum recorded at 10 eV pass energy demonstrates the excellent spectral resolution achieved on these irregular, highly insulating samples. The resolution allows confident identification of many of the chemical functionalities present:
C-H; C-CF/C-CO2; C-CFn/C-O; C-F/C=O; CF-CFn/CO2; CF2; and CF3.

41. XPS Analysis of Plasma Deposited Coatings
Overlay of C 1s spectra recorded from the wet chemical fluorosolvent treated fabric before washing, after 5 washes and after 5 washes and ironing.
Wet chemical treatment
5 Washes
5 washes + ironing
High resolution C 1s spectrum of wet chemical fluorosolvent treated nylon after 1 wash and 5 washes demonstrating loss of surface coating

42. Small area analysis

43. The Selected Area Aperture

44. Selected Area Aperture
The selected area aperture is used to define a small analysis area at the surface. There are two approaches that may be adopted to allow XPS analysis from areas in the micron range. One approach is ti insert an aperture into the electrostatic lens column, as shown in the figures below, to forma virtual probe at the surface. An alternative approach is to use a focussed excitation source with the transfer lens collecting photoelectrons from the irradiated area. Selected area spectroscopy and mapping is descried in greater detail in technical note MO224 (available from Kratos Analytical).
110mm analysis area 27mm analysis area
Selected area apertures
Angle defining iris
Analyser entrance slit
Electrostatic lens column

45. AXIS Electron Optics : Selected Area and Scanned Imaging
Plan view of sample x y
Selected area apertures
Angle defining iris
Analyser entrance slit
Beam scanning plates, x & y
27mm analysis area
Fixed x,y voltage applied to scan plates to deflect analysis position to defined position on sample.
Scanning x,y voltage applied to scan plates to deflect analysis position over defined area of sample to generate a map.

46. Plasma modification and Patterning
Substrate : Polystyrene with surface modified by exposure to CFx containing plasma.
TEM grid then used as a mask and sample reintroduced into a plasma chamber.
Substrate and grid exposed to C-O, C-N containing plasma.
Can pattern be observed?
What further information can be extracted from the images? PS
CFx
functional groups PS
C-O,C-N
functional groups

47. Plasma modification and Patterning
As the sample was a clear polymer sheet with thin plasma modified layer there was nothing to see optically.
A large area (300x700um) survey spectrum acquired from the sample showed photoelectron peaks from fluorine, oxygen, nitrogen and carbon.
A quick parallel image corresponding to the fluorine gave a well resolved grid pattern.
To better characterise the chemistry of the surface small spot spectra were acquired.
- Large area (300x700um) survey scan from patterned area
F 1s
O 1s
N 1s
C 1s
- F 1s parallel image for 60 sec.

48. Defining the selected area spectrum position
The parallel image is used to define the position for the small spot spectra by simply clicking with the mouse and importing the position into the acquisition software shown to the right.
The virtual probe is deflected to the defined position using the beam scanning plates.
CF3
CF2
CC,CH
CO,CN

49. Imaging XPS

50. The Spherical Mirror Analyser (SMA)

51. Parallel Imaging Mode of AXIS Ultra
Outer hemisphere
of HSA
Charge neutraliser
Spherical mirror analyser (SMA)
Hemispherical analyser (HSA)
Magnetic lens
Sample
Selected area aperture
Objective lens
Delayline detector
Retarding
projector
lens
Objective lens produces magnified photoelectron image I1
Projector lens produces image I2 retards to pass energy E0
Magnification at detector variable from <5x to >100x
Field of view on sample from >2mm to <100mm
Lateral resolution to <2mm
Operation in FAT mode and provides energy resolution comparable to HSA. I1 I2

52. SMA and Parallel Imaging
Fast Parallel XPS Imaging
as the sample is moved, so the photoelectron image moves.
Lateral Resolution specification < 3 mm
Fixed analyser transmission (FAT) mode
energy resolution constant at all binding energies.
good energy resolution at all binding energies.
‘Real time’ chemical state XPS imaging
ability to differentiate between elements in different chemical states.

53. Variable Field of View - Real Time Imaging of Au grid
800 mm fov
400 mm fov
400 mm fov
2 mm fov
200 mm fov
Au images acquired in less than 60 secs.
Field of view (f.o.v.) changed by selecting predefined lens modes for a specific magnification. The new f.o.v. is displayed within seconds.

54. XPS Imaging of 5 mm Cu Bars
2.2 mm edge
25mm from centre of bars
After acquisition of the image a line scan can be generated. The line-scan can be processed to provide edge measurements, giving an indication of lateral resolution

55. Fast real-time imaging
Au finder grid
Parallel images acquired in 5,10, 20 and 60 seconds
Fast photoelectron images allow easy sample alignment
As sample moves … image moves!!

56. Large area fast parallel imaging
3.2 x 3.2mm image
7um spatial resolution
300 sec total acquisition time
1.6 x 1.6mm image
3um spatial resolution
300 sec total acquisition time

57. Spectra from Images With AXIS Ultra
The experiment requires the acquisition of a sequence of images over any energy range.
eV with 0.2 eV steps corresponding to C 1s region.
30 sec per image - total acquisition 75 mins
Sum intensity of pixels within defined area to obtain spectral information form that area
Set of images as a function of Binding
Energy (eV)
x (mm)
y(mm)
256x256 pixels
270eV
300eV

58. Spectra from images As generated
It is possible to use the image dataset to reconstruct a spectrum. The example below shows a spectrum generated from a single pixel (blue) using the raw images. When the noise has been removed from the image dataset using the PCA approach a much more convincing spectrum is shown.
This spectrum was defined from a single pixel 1.4 x 1.4um area ! It is possible to generate a spectrum from any of the 256 x 256 pixels on the imaged area – over 65,500 spectra !!
As generated
spectrum generated from significant PCA components

59. Spectra from Images C 1s spectrum generated from 5x5 pixels -CF2
CC,CH CO
C=O
-CF2
-CF3
After generating spectrum from images it is then possible to deconvolute the data and fit with components.
An image may then be generated corresponding to a specific component.
Has the advantage that peak shifts may be accommodated in by the model.
Integrating area under the peak allows chemical state images show relative concentrations.

60. Quantitative Elemental and Chemical State Imaging
CH, CC CO, CN C=O CF2
-CF Fluorine Nitrogen Oxygen

61. Large area imaging – image stitching

62. CdTe / CdS / ZTO / CTO / glass stack
ZTO (ZnSnO)
CTO (CdSnO)
CdS
CdTe
Approximate
thickeness / nm 20
XPS imaging used for film continuity

63. NREL CIGS Sample : XPS images
100 mm
In photoelectron image
90 sec acquisition
100 mm
Na photoelectron image
240 sec acquisition

64. NREL CIGS Sample : XPS stitched images
In XPS image
(9x4) stitch
Na XPS image
1mm
1mm

65. NREL CIGS Sample : XPS stitched images
Overlay of In (9x4) stitched image (red) and Na (9x4) stitched image (blue)

66. NREL CIGS Sample : selected area XPS
Na 1s
Cu 2p
O KLL
In MNN
In 3p
O 1s
In 3d
Na KLL
C 1s
Se 3p
Se LMM
Se 3d
Na 2s
Ga 3d / In 4d
27um selected area XPS
100 mm
defect
substrate

67. Angle resolved XPS

68. Angular Dependence of XPS
photoelectrons
photoelectrons
X-rays
X-rays d d
d ~ 8-10 nm

69. Si wafer with native oxide
Carbon
Si Oxide
Si Bulk
0° to sample normal
Bulk Sensitive
70° to sample normal
Surface Sensitive
Si 2p1/2
Si 2p3/2
Si Hydroxide
Si oxide

70. Si wafer with native oxide
Si sample with native oxide was not cleaned prior to analysis.
Sample tilted from 0° through 70° with steps of 10°
The contribution from Si oxide and Si hydroxide convoluted components have been combined.

71. MEMs Depth Profile Reconstruction for Si wafer with native oxide

72. ‘Banana Shaped’ SAM Molecules
Sample A – 14-F-P-11a
Sample B – 14-P-F-11a
Chemical Formula – C59H69FO10
HF used for the removal of native oxide on Si wafer.
Hydrogen terminated Si-surface covalently reacts with alkene chain end to form strong Si-C bonds
Detailed studies using AFM, water contact angle and ATR-FTIR techniques have shown that the monolayer is densely packed and well ordered.

73. ‘Banana Shaped’ SAM Molecules
Sample A – 14-F-P-11a
Sample B – 14-P-F-11a

74. MEMs Depth Profile Reconstruction – Sample A

75. MEMs Depth Profile Reconstruction – Sample B

76. MEMs Depth Profile Reconstruction – Depth Distribution of Fluorine
Sample A
Sample B

77. XPS depth profiling - inorganics
Accepted standard technique for analysis of inorganic samples
Improvements in small spot XPS mean small etch craters can be used
Etch rates in the range of 1 – 50nm min-1 (Ta2O5)
Recent advances in ion gun technology have lead to lower primary ion energies for improved interface resolution.

78. Al2O3-Mg2F-SiO2-Si 250V beam energy
Al 2p
F 1s
Mg 2p
Si Oxide
Si Elemental

79. Multilayer sample 750 V Ar+
Etch conditions: 750 V, 3 x 3 mm raster, 60 s etch cycles.
Etch rate on Ta2O5: 2.3 nm/min
Acquisition: 10 s snapshot spectra, cycle time 2min 50 s
Total acquisition time: ~14 hours
width of last Al layer
fwhm 63nm
width of 1st Al layer
fwhm 58nm

80. Multilayer sample 750 V Ar+
Example of 10s Ga 2p snapshot spectra
110 µm are of analysis
surface
layer 1
layer 3
layer 5

81. SiC/Si : high resolution snapshot spectra
Si 2p region
Si (elemental)
Si (carbide)
Si (oxide)

82. SiC/Si : Elemental depth profile
Oxygen
Silicon
Carbon
750 V Ar+ ions
3x3mm rastered crater

83. SiC/Si : Si chemical state depth profile
Si (elemental)
Si (carbide) 1
surface 3
SiC/Si interface
Si (elemental)
Si (oxide)
Si (carbide)
Si (oxide)
Si (elemental)
Si (oxide)
Si (carbide) 2
SiC sub-surface 4
bulk
Si (elemental)
Si (elemental)
Si (carbide) 1 2 3 4

84. Auger electron spectroscopy - AES

85. FE-Auger Electron Source
Field emission electron source and ion pump shown here in situ on an AXIS Ultra.

86. Hi Magnification SEM with Linescan
5 microns
266 nm resolution measured using
80% - 20% line scan from SiO2 / Si
sample.

87. Si KLL Auger spectra
Si KLL oxide
Si KLL elemental

88. Si wide scan Auger spectra

89. O KLL Auger map and SEM
20 microns

90. Atmospheric corrosion of nickel SEM images
The atmospheric corrosion of nickel in a rural atmosphere – the formation of sulfate-containing
corrosion products with a characteristic dendritic morphology.
I.Odnevall & C. Leygraf J.Electrochem. Soc., vol 144, No. 10, October 1997,

91. Atmospheric corrosion of nickel AES after light etch
substrate Ni Ni X Ni O C X
dendrite O S Ni Ni Ni
AES spectra show the presence of sulfur in
the dendritic structure only. C

92. Atmospheric corrosion of nickel AES maps
S (p-b) map
O (p-b) map
Ni (p-b) map
The images shown are peak - background maps.

93. Duplex stainless steel UNS S32750 SEM & AES
In duplex stainless steels the alloying elements are not uniformly distributed
between the two phases (austenite and ferrite). For example Cr and Mo partition
to the ferrite phase and Ni and N to the austenite.
austenite - light Fe Cr Fe Cr Fe X Ni C Ni
ferrite X
austenite
ferrite - dark Cr
ferrite Cr Fe Fe Fe
The sample was etched to remove the surface oxide before the SEM
and AES were acquired. There was a slight difference in the Cr intensity
between the two areas. Cr and Ni maps were acquired to investigate
any spatial differences in their concentrations. C Ni Ni
M. Femenia, J. Panl & C. Leygraf J.Electrochem. Soc., 151, (10) B581-B585 (2004)

94. Duplex stainless steel UNS S32750 AES maps
Cr p-b map
Ni p-b map
The Cr concentration is highest in the ferrite where the Ni concentration is lowest (austenite). The N concentration should be highest in the austenite region. Further AES spectra, with longer acquisition times, were recorded to try and detect the low level of nitrogen present.

95. SEM Image of 1 micron Au Pattern on integrated IC
An SEM image of the Au pattern was recorded using a 30 micron field of view.

96. SEM Image of 1 micron Au Pattern
Line scan used to measure one of the Au lines from the SEM image

97. Auger Spectroscopy Au MNN Al KLL Au OPP O KLL C KLL S LMM
Auger spectra were recorded from on one of the pads (red) and the substrate (blue)
Al LMM

98. Back Scattered Image of 1 micron Au Pattern
Sample was then etched and a back scattered image recorded with a 10 micron field of view.

99. Auger Maps
Auger maps were recorded of the Au MNN and Al KLL peaks. Images displayed below are peak minus background maps recorded using 64 x 64 pixels and 100 ms dwell time. Total time for each image was 410 seconds (820 seconds for peak and background).
Al KLL Map
Au MNN Map

100. Auger Maps
Overlay of Au MNN and Al KLL peak minus background maps recorded using 150 x 150 pixels and 50 ms dwell time.

101. Auger Maps: 100nm spatial resolution
100 nm 80/20 resolution measured across a feature in Auger mapping mode.

102. Corrosion Pit: Cu on Au
An SEM image of a corrosion pit was recorded using a 400 micron field of view.

103. Auger Spectroscopy In corrosion pit Outer ring Corrosion pit Au MNN
Auger spectra were recorded from in the corrosion pit (left) and the outer ring (right)
Cu LMM
Cl LMM
O KLL
S LMM
Au NOO

104. Auger Maps
Au MNN Map
Cl KLL Map
S LMM Map
Cu LMM Map

105. Sample 4 : Auger Maps
Overlay of Au (red), Cu (green) and Cl (blue) peak minus background Auger maps

106. SEM Image of Corrosion Pit following an etch
An SEM image of a corrosion pit was recorded following an Ar ion etch

107. Auger Spectroscopy of corrosion product
Auger spectrum recorded from the corrosion product
Cu LMM
Cl LMM
O KLL

108. Ultra Violet Photon Source
Optimized for maximum He (I) or He (II) (or Ne (l)/Ne (ll)) output.
1mm diameter guide to give a maximum lamp current of 37mA at17.5W
Minimum step size energy scale is 0.25meV in UPS mode.

109. Ag 4d reference data: UPS
>1.5MCPS
Ag EF = 95 meV.

110. Ag 4d reference data: UPS
Hi (II) Ag 4d

111. XPS/UPS of synthetic diamond
Optical image of
synthetic diamond

112. XPS/UPS of DLC Element O 1s C 1s rel. atomic conc. 30.8 70.2 O 1s C 1s
O KLL

113. In-situ heating of DLC sample
Sample heated to 450°C to reduce contamination
Heating and cooling controlled directly from software

114. Post annealing Element O 1s C 1s rel. atomic conc. (% 1.3 98.7 C KLL
O KLL

115. Φ= 4.15eV Heated Diamond Sample – He (I) UPS EO= 17.8eV
Φ= 21.22eV – (17.8eV – 0.73eV)
Φ= 4.15eV
EF = 0.73eV

116. Small area XPS and XPS imaging
Teflon tube
Silicon containing
plasma

117. Plasma treated polymer tube : survey spectra
scanned spectra
plasma treated
end of tube
cut end of tube
Si 2p
Si 2s
C 1s
N 1s
O 1s
F 1s
F KLL
O KLL
survey spectra from 110um analysis area

118. Concentration line scan by 110um, classic small area analysis
Several mm’s
Plasma

119. Plasma treated polymer tube : high resolution spectra
scanned spectra
N 1s region
Si 2p1s region
plasma
treated
end of tube
cut end of tube
C 1s region

120. Plasma treated polymer tube : high resolution spectra
CC,CH
C-O/C-N
C=O/CF
CF2
CF3
plasma treated end
bulk polymer end
representative C 1s spectra as a function of position from the end of the tube

121. Plasma treated polymer tube : Chemical state images
CC,CH (peak-background)
parallel image at 285eV
120 sec acquisition
CF2 (peak-background)
parallel image at 292eV
120 sec acquisition
overlay of CC,CH (red) with
CF2 (green) parallel images

122. Plasma treated polymer tube : elemental images
800 mm2 field of view
CF2 (peak-background) F 1s (peak-background)
120 sec acquisition sec acquisition

123. Plasma treated polymer tube : chemical state & elemental images
400 mm2 field of view
CC,CH (peak-background)
parallel image at 285eV
180 sec acquisition
CF2 (peak-background)
parallel image at 292eV
180 sec acquisition
F 1s (peak-background)
parallel image at 689eV
90 sec acquisition

124. Plasma treated polymer tube : selected area spectroscopy
400 mm2 field of view
Analysis position
Atomic
Concn   %
Fluorine
Oxygen
Nitrogen
Carbon
Silicon
Point 1
45.87
4.66
1.74
45.34
2.39
Point 2
27.33
9.87
6.11
50.07
6.72
55um analysis area
p1 (substrate)
p2 (plasma polymer)
F 1s
O 1s
N 1s
C 1s
Si 2p
Si 2s

125. Plasma treated polymer tube : selected area spectroscopy
400 mm2 field of view 2 1
55um analysis point 1
55um analysis point 2
F-Si (inorganic)
C-F2 - organic
CC,CH
C-O/C-N
C=O/CF
CF2
CF3

126. Stitched images - 12 x 800 mm2 field of view
F 1s image 30 sec per image
Total acquisition time 5 mins
open, plasma treated end cut end of tube
Si concentration F concentration

127. Quantitative imaging and multivariate analysis
Value can be added to XPS images by the use of multivariate analysis methods
Here a disc shape specimen of ASTM F 138 stainless steel, shown in the optical image above was machined, electropolished and laser marked. The area of interest is shown in the expanded view with the blue box indicting the area imaged with XPS.

128. Medical grade stainless steel Fe 2p images
Sum of pixels
(raw data)
Fe 2p3/2
Acquire
Fe 2p3/2 multi-spectral images eV, 0.25eV steps, 30 s per image
Cr 2p multi-spectral images, 0.25eV steps, 30 s per image
Fe 2p images
719eV 710eV (oxide) 706.5eV (metal) 700eV background
binding energy

129. Fe 2p3/2 region abstract factors
(1) Mean AF (2) Maximum variance
(3) (4)
Acquire
Fe 2p3/2 multi-spectral images eV, 0.25eV steps, 30 s per image
Cr 2p multi-spectral images, 0.25eV steps, 30 s per image
Process:
Convert image dataset to 256 x 256 spectra at a pixel
SVD sort / reduced PCA to order AF’s
Construct images from the first 2 abstract factors

130. Raw & SVD/reduced PCA processed data
Summed pixel intensity from 256x256 pixels
Raw data
SVD/reduced PCA processed
Fit components to processed data corresponding to Fe oxide and Fe metal
Single pixel spectrum from metallic region
Single pixel spectrum from oxide region

131. Quantitative Cr and Fe images
Chromium relative atomic concentration image
Iron (metal) relative atomic concentration image
Cr image (red) shows enhanced concentration at the edge of the laser marked area
Cr rich region at ‘corrosion front’
Fe metal (green) across entire sample but much lower concentration on laser marked area
oxide layer thicker in laser marked area attenuates the Fe metallic signal

132. Pixel grouping False colour range used to assign pixels
Fe 2p 3/2
METAL
OXIDE
False colour range used to assign pixels
Raw pixels then summed to give “true” spectra from oxide and metal region

133. Monomers used to generate sample array
Image stitching – high spatial resolution over large image areas
Monomers used to generate sample array
glass slide
poly(hydroxyethyl methacrylate)
(pHEMA)
Acrylate, diacrylate, dimethylacrylate and triacrylate combinations (as above)
1:40pm BO+PS+AS+SS TuA1 Room 201
“High throughput surface chemical analysis of polymer microarrays: Wettability, protein adsorption and cell response”
D.G. Anderson, S. Levenberg & R. Langer Nature Biotechnology 22 (7)

134. Quantitative elemental stitched images
2mm
Fluorine (peak-background) Oxygen (peak-background) Carbon (peak-background)
Quantitative elemental images corrected for transmission function and RSF
Thermal scale now indicates relative atomic concentration at a pixel
- each pixel represents 6.25um on the surface

135. Quantitative elemental stitched images
Fluorine
11.4 at%
0 at%
90.6 at% at%
Carbon
Oxygen
32.5 at%
7.1 at%
2mm

136. 10 reasons why Axis Ultra is best selling XPS
Only instrument to offer 400,000CPS
Excellent performance on insulators < 0.68eV PET
Largest analyser 165mm radius
DLD – pulse counting quantitative parallel imaging
DLD – snapshot mode 128 data channels
Fully automated control of all spot sizes
Electron only charge neutralisation system
Smallest analysis area 15um
Two analysers optimised for imaging and spectroscopy
Electrostatic deflection system for small area spectroscopy