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Compucentric Zalar rotation depth profiling

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Compucentric Zalar rotation depth profiling
PHI 710 Scanning Auger Nanoprobe
Complete Auger Compositional Analysis
for Nanotechnology, Semiconductors,
Advanced Metallurgy and Advanced Materials
www.phi.com
1
PHI Auger 710
Superior Analytical Capabilities
 Nanoscale image resolution
 Image registration for high sensitivity
 Constant sensitivity for all sample geometries
 High sensitivity at low tilt angles for insulator analysis
 Nano-volume depth profiling
 Chemical state analysis: spectra, imaging, depth profiling
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2
PHI 710 Secondary Electron Imaging (SEI)
3 nm from Au Islands on Carbon
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3
PHI 710: High Spatial Resolution Auger
BAM-L200 Standard Sample
AlGaAs Line Width (nm)
Locations for Line Scans Area Analyzed
4 nm Al Line
1
2
Auger
Line
Scans
3
4
Ga Map
25kV; 1nA
256x256 pixels
Line Analysis
Al Map
25kV; 1nA
256x256 pixels
24 Hour stability test demonstrating exceptional image registry
Sample provided by Federal Institute for Materials Research and Testing (BAM)
Berlin, Germany
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Line Analysis
PHI 710: High Spatial Resolution Auger
BAM-L200 Standard Sample
Line Scan #4
Intensity
Ga
Al (X3)
4 nm Line
0
0.05
0.1
0.15
0.2
Distance (µm)
0.25
0.3
0.35
24 hour analysis demonstrating exceptional image registration
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5
Constant Sensitivity for All Geometries
Minimum Beam Diameter
2,000
1,800
1,600
Sensitivity (kcps)
MultiChannel
Detector
Sensitivity vs. Sample Tilt
Field
Emission
Electron
Source
Cylindrical
Mirror
Analyzer
1,400
1,200
1,000
800
Coaxial CMA
600
400
Non-Coaxial SCA
200
0
-90 -75 -60 -45 -30 -15 0
15 30 45 60 75 90
Tilt Angle (degree)
Ar+ Ion Gun
Sample holder with high energy resolution optics
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The CMA with a coaxial electron
gun provides high sensitivity at all
sample tilt angles which is
essential for insulator analysis
6
CMA with Coaxial Electron Gun
Only the PHI 710 can image samples such as
FIB sections with uniform, high sensitivity
Poly-Si/W Deposition and Patterning
Auger Analysis of ex situ FIB cut
Auger maps show:
 Defect is sub-micron Si oxide particle
 Surrounded by elemental Si
 Introduced during poly-Si deposition
 Covered with W
Auger Maps:
Si oxide
Si elemental
W
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7
PHI CMA High Energy Resolution Mode
 How does the high energy resolution mode work?
– The CMA energy resolution is given as:
– ΔE / E = 0.5%
– An optics element placed between the sample surface and
the entrance to the standard CMA retards the Auger
electrons, reducing their energy, E
– From the energy resolution equation, if E is reduced, ΔE is
also reduced and so is the Auger peak width; energy
resolution is improved
– The CMA is not modified in any way and retains a 360º
coaxial view of the sample relative to the axis of the electron
gun
– US Patent 12 / 705,261
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8
PHI CMA High Energy Resolution Mode
710 Energy Resolution Specification
0.6
ΔE / E (%)
0.5
0.4
0.3
0.2
0.1
0.0
0
500
1000
1500
2000
2500
Auger Peak Kinetic Energy (eV)
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9
PHI CMA High Energy Resolution Mode
Al KLL Spectra of Native Oxide on Al Foil
350
0.5%
0.1%
300
250
N(E) cps
200
150
100
50
0
1386.9 eV (Al oxide)
-50
1350
1360
1370
1393.4 (Al metal)
1380
1390
Kinetic Energy (eV)
1400
1410
1420
Auger KLL spectrum of native oxide on Al foil measured on PHI CMA at 0.5%
(blue) and 0.1% (red) energy resolution, after background subtraction.
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10
PHI CMA High Energy Resolution Mode
Zn LMM Spectra of Sputter Cleaned Zn Metal
1
0.5% Energy Resolution
0.1% Energy Resolution
0.9
0.8
Normalized Intensity
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
970
980
990
1000
1010
Kinetic Energy (eV)
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1020
1030
11
PHI CMA High Energy Resolution Mode
Depth Profile of Native Oxide on Si
4
0.1% Energy Resolution
x 10
Si elemental
8
6
Si oxide
c/s
4
Si plasmons
2
0
10 kV - 10 nA
20 µm defocused beam
4 minutes per cycle
-2
60
40
20
0
1580
1590
1600
1610
1620
1630
Kinetic Energy (eV)
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12
PHI CMA High Energy Resolution Mode
Depth Profile of Zn Oxide on Zn
Zn oxide
Zn metal
5
x 10
9.8
9.6
9.4
c/s
9.2
9
10
8.8
5
8.6
8.4
0
970
980
990
1000
1010
Kinetic Energy (eV)
www.phi.com
1020
1030
13
PHI 710 Spectral Window Imaging
IC.401.sem: Pad 41
IC412_256.map:
PHI Pad 41
PHI Pad 41
IC412_256.map:
2012 Sep 21 10.0 kV 10 nA FRR
2012 Sep 22 10.0 kV 10 nA FRR
2012 Sep0.00
22 s10.0 kV 10 nA FRR
Si4/-1RSF
Si4/-1RSF
SEM/-1
SEI
SEM
B
4094
Si KLL Peak
Area
Si4
RSF
Silicide
Si4.ls1
C
3462175
IC412_256.map: 20
Padµm
41
892.8 PHI Pad 41
IC412_256.map:
2012 Sep 22 10.0 kV 10 nA FRR
2012 Sep
22s 10.0 kV 10 nA FRR
0.00
IC412_256.map:
1137329 PHI Pad 41
20 µm
0.00
2012 Sep
22 s 10.0 kV 10 nA FRR
Si4/-1
Si4/-1
RSF
Si4/-1RSF
20 µm
Elemental
Si
Si4.ls2
Si Oxynitride
Si4.ls3
E
32297
20 µm
7465
F
32297
7465 PHI
0.00 s
RSF
Si Chemical
States
Si4.ls1+Si4.ls2+Si4.ls3
47.0
20 µm
20 µm
20 µm
D
32297
20 µm
20 µm
20 µm
A
PHI
0.00 s
7465
20 µm
20 µm
0.0
Panel A shows a 200 µm FOV SEI of a semiconductor bond pad. Panel B shows the Si KLL peak area
image from the area of panel A. Panels C, D and E show the chemical state images of silicide, elemental
Si and Si oxynitride respectively. Panel F shows a color overlay of elemental silicon, silicide and silicon
oxynitride images.
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14
PHI 710 Spectral Window Imaging
IC412_256.map: Pad 41
PHI
2012 Sep 22 10.0 kV 10 nA FRR
Si4/-1
Composite Si KLL
A
0.00 s
with ROI areas
B Si KLL image
Si4
RSF
20 µm
1605
1615
1625
Kinetic Energy (eV)
1137329
20 µm
C
Si KLL Basis Spectra
Si Oxynitride
Silicide
Intensity
Panel A shows the Si KLL
spectrum from the sum of
all pixel spectra in the Si
KLL Auger image shown in
panel B. Panel B shows
the three Regions Of
Interest (ROI) selected for
creation of the basis
spectra for Linear Least
Squares (LLS) fitting of the
Si KLL image data set.
Panel C shows the three
basis spectra with their
corresponding chemical
state identifications.
Intensity
3462175
Elemental Si
PHI App. Note: Chemical State Imaging With
The PHI 710 Scanning Auger NanoProbe
1604
1608
www.phi.com
1612
1616
Kinetic Energy (eV)
1620
1624
15
Nanocone Imaging
Auger Images Suggest
Larger Nanocone Surface Composed of Silicon Oxide and Nitride
Smaller Silicon Oxide Feature
Smaller Silicon Oxide Feature
2O kV – 10 nA
SEI
N Map
256 x 256 pixels
HR Si-oxide Map at 0.1% Energy Resolution
Only the larger Nanocone contains N
Both the large and small features contain Silicon oxide
The composition suggested by the images is confirmed with high energy resolution analysis
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16
Nanocone Chemical Analysis
Large Nanocone Base
0.1% Energy Resolution
Si Oxide
Standard
Si Nitride
Standard
1
Si KLL
Normalized Intensity
0.8
0.6
0.4
0.2
20 kV – 10 nA
0
1600
1605
1610
1615
1620
Kinetic Energy (eV)
1625
1630
Nanocone base is mixture of silicon oxide and silicon nitride
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17
PHI 710 Advantages
 World’s best Auger depth profiling
– Floating column ion gun for high current, low voltage depth
profiling
– Compucentric Zalar Rotation™ maximizes depth resolution
– Image registration maintains field-of-view
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18
Low Voltage Depth Profiling
Improved Interface Definition with use of Ultra Low Ion Energies
500 eV Depth Profile
100 eV Depth Profile
Al
Intensity
Intensity
Al
0
Ga
Ga
As
As
0
10
20
30
Sputter Time (min)
200
400
600
Sputter Time (min)
800
Improved definition of layers
AlAs/GaAs Super Lattice Sample
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19
Nano Depth Profiling
60 nm Diameter Si Nanowire
4
1
Surface Spectrum of Nanowire A
x 10
Atomic %
Si 97.5
P
2.5
SEI
0.5
0
P
c/s
1
-0.5
O
-1
20 kV, 10 nA, 13 nm Beam
FOV: 2.0 µm
F
0.5 µm
-1.5
C
Si
-2
100
200
300
400
500
600
Kinetic Energy (eV)
700
800
P from the growth gas is detected on the surface of a Si nanowire
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20
Non-homogeneous P Doping of Si Nanowires
Depth Profile of Nanowire B

500 V Ar sputter depth profiling shows a non-homogeneous radial P distribution.

The data suggests Vapor-Solid incorporation of P rather than Vapor-Liquid-Solid P incorporation
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21
Compucentric Zalar Rotation Depth Profiling
Ion Beam
Compucentric Zalar rotation depth
profiling defines the selected analysis
point as the center of rotation. This is
accomplished by moving the sample in
X and Y while rotating, all under
software control.
Analysis
Area
Micro-area Zalar depth profiling is
possible on features as small as 10 µm
with the 710’s automated sample stage.
Sample
Zalar rotation is used to eliminate
sample roughening that can occur
when sputtering at a fixed angle.
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22
Compucentric Zalar Rotation Depth Profiling
Compucentric Zalar Depth Profile of 10 µm Via Contact
100
Atomic Concentration (%)
Al (metal)
Si
80
O
60
40
Al (oxide)
20
Secondary Electron Image
(Before Sputtering)
0
0
www.phi.com
50
100
150
200
250
Sputter Time (min)
300
23
Compucentric Zalar Rotation Depth Profiling
Depth Profile Comparison With and Without Zalar Rotation
100
100
Al (metal)
80
Atomic Concentration (%)
Atomic Concentration (%)
Al (metal)
Si
O
60
40
Al (oxide)
0
80
O
60
40
Al (oxide)
20
20
0
Si
50
100
150
200
250
Sputter Time (min)
300
With Rotation
0
0
50
100 150
200
250
Sputter Time (min)
300
Without Rotation
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24
Compucentric Zalar Rotation Depth Profiling
SE Images of 10 µm Via Contacts
after Depth Profiling
2500X
2500X
With Rotation
Without Rotation
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25
Large Area Chemical Depth Profile of Ni/Si Wafer
Annealed at 425 ºC
Elemental Depth Profile
300
0.1% Energy Resolution
10 kV-10 nA
20 µm Average
As Received
Ni LMM
Si KLL
Sputter Conditions:
500 V Argon
1 x 0.5 mm raster
200
Intensity (kcps)
No Zalar Rotation
10° Sample Tilt
100
Chemical State of Ni ?
Chemical State of Si ?
0
0
10
20
30
Sputter Time (min)
www.phi.com
40
50
60
26
Large Area Chemical Depth Profile of Ni/Si Wafer
Annealed at 425 ºC
Si Chemical Depth Profile Created Using Linear Least Squares Fitting
Si KLL
Intensity (kcps)
200
Si in
Si substrate
100
Si in Ni layer
0
0
10
20
30
Sputter Time (min)
www.phi.com
40
50
60
27
Large Area Chemical Depth Profile of Ni/Si Wafer
Annealed at 425 ºC
0.1% Energy Resolution
Si basis spectra for LLS (expanded)
Si basis spectra for LLS
Si KLL
Si KLL
Si in
Si substrate
Si in Ni layer
Normalized Intensity
1570
Si in Ni layer
Normalized Intensity
Si in
Si substrate
1590
1610
Kinetic Energy (eV)
1630
1610
1615
1620
Kinetic Energy (eV)
1616.5 eV
(metal)
www.phi.com
1625
1617.2 eV
(silicide)
28
Large Area Chemical Depth Profile of Ni/Si Wafer
Annealed at 425 ºC
Si Chemical Depth Profile Created Using Linear Least Squares Fitting
300
0.1% Energy Resolution
Intensity (kcps)
Ni LMM
Ni in Ni layer
200
Ni in
Si substrate
100
0
0
10
20
30
Sputter Time (min)
www.phi.com
40
50
60
29
Large Area Chemical Depth Profile of Ni/Si Wafer
Annealed at 425 ºC
0.1% Energy Resolution
Ni basis spectra for LLS
Ni basis spectra for LLS (expanded)
Ni LMM
Ni LMM
810
820
830
Ni in Ni layer
840 850 860
Kinetic Energy (eV)
Normalized Intensity
Normalized Intensity
Ni in
Si substrate
870
830
880
Ni in
Si substrate
835
840
845
850
Kinetic Energy (eV)
844.8 eV
(Ni-silicide)
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Ni in Ni layer
855
860
846.2 eV
(Ni-metal)
30
Large Area Chemical Depth Profile of Ni/Si Wafer
Annealed at 425 ºC
After Depth Profile
2
Intensity (Mcps)
2.5
1
Si
Si
2.0
Ni
1.5
Ni
Ni
|
|
Si
|
|
Point 1
Ni
Point 2
C
1.0
FOV: 5.0 µm
F
SEM
Fe3C
20kV - 1nA
20.000 keV
1.0 µm
Si
C
2/16/2010
22 nm beam size
Analysis points
500
 Auger multi-point analysis shows
composition of nano-structures
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1000
1500
Kinetic Energy (eV)
2000
Point 1: Ni-silicide
Point 2: Si-metal
31
Large Area Chemical Depth Profile of Ni/Si Wafer
Annealed at 425 ºC
After Depth Profile
0.1% Energy Resolution
Si KLL
Point 2
Si in
Si substrate
Point 1
Si in Ni layer
Point 2
Si in
Si substrate
Point 1
Si in Ni layer
Normalized Intensity
Normalized Intensity
22 nm beam size
Si KLL (expanded)
22 nm beam size
1570
1580
1590
1600 1610 1620
Kinetic Energy (eV)
1630
1640
1610
1615
1620
Kinetic Energy (eV)
1616.5 eV
(metal)
www.phi.com
1625
1617.2 eV
(silicide)
32
Ni/Si Annealed at 425 °C
12 nm Removed
Nano-areas selected for depth profiling
2
2
1
FOV: 5.0 µm
F
SEM
Ni/Si 425C
20 kV - 10 nA
20.000 keV
1
1.0 µm
3/30/2010
Analysis points
Auger Color Overlay
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20 kV - 10 nA 256 x 256 pixels
33
Nano Area Chemical Depth Profile of Ni/Si Wafer
Point 1 – Ni Layer
Chemical Depth Profile Created Using Linear Least Squares Fitting
Ni metal
Si metal
Intensity (kcps)
200
Sputter Conditions:
500 V Argon
1 x 0.5 mm raster
10 kV – 10 nA
Point 1
LLS Profile
No Zalar Rotation
10° Sample Tilt
100
Si silicide
Ni silicide
22 nm beam size
0
0
20
40
60
80
100
120
Sputter Depth (nm)
140
160
180
200
 Nano area depth profile shows nickel silicide at the nickel / silicon interface
 Large area depth profile included heterogeneous distributions of nickel silicide
that grows through imperfections in Ni film
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34
PHI 710 Scanning Auger Nanoprobe
Multi-technique Options
Energy Dispersive Spectroscopy (EDS or EDX)
Backscatter Electron Detector (BSE)
Electron Backscatter Diffraction (EBSD)
Focused Ion Beam (FIB)
The Complete Auger Solution
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35
PHI 710 Chamber Layout for Options
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36
PHI 710 Scanning Auger Nanoprobe
Complete Auger Compositional Analysis
for Nanotechnology, Semiconductors,
Advanced Metallurgy and Advanced Materials
www.phi.com
37
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