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Product NO : TII-1 |
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3D Raman Microscopy System, Micro-Nano Scale Micro spectroscopy Nanofinder®30 |
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UV system for strained Si measurements
 Stress measurement of Si device
Local stress on the surface of a Si device can
be evaluated by analyzing the shift of the Si
Raman peak. For this measurement
Nanofinder®30 UV model
was developed. The UV model combines both: high
spatial and spectral resolution.
To obtain high spectral resolution (0.5
cm-1) and high throughput (30%) the
52 cm focal length spectrometer was designed to
adopt an Echelle grating. To get the same
spectral resolution with standard spectrometer
it is necessary to use much larger device (1.3
m focal length).
Si stress measurement resolution
With 52 cm spectrometer, equipped with an Echelle grating it is possible to measure:
Strain of 0.05 % <0.5 cm-1 @364 nm (hardware resolution)
Strain of 0.01 % <0.1 cm-1 (spectral line fitting software).
Non-destructive analysis
Using resonance excitation a low laser power is sufficient to
acquire Raman spectra with narrow bandwidth (no sample heating) and
good S/N ratio.
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Si Raman peak at 520 cm-1
Minimum distortion of data.
Sample: monocrystalline Si
Laser wavelength: 364 nm
Exposure: 1 sec
Laser power: 0.4 mW
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Si stress
distribution image
Area: 5.5 ×
5.5 μm,
Laser power: 0.4 mW
Mapping step: 100 nm (55×55
points)
Exposure: 0.1 sec/point,
Total measurement time: 5min.
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Ar-ion excitation laser at 364 nm line
With the 364 nm excitation wavelength the
penetration depth inside Si wafer is only 4 nm:
an extremely thin surface layer can be
measured. Confocal optics and optics inside
spectrometer are optimized for UV
excitation. Optimized optics for UV-VIS
excitation is also available.
Highest spatial resolution
With UV excitation wavelength and optimized confocal optics lateral
resolution of 130 nm (as shown in the figure below) is possible.
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Step response in lateral direction of < 130 nm
Step response = distance, when signal increased from 10% to 90% from maximum value.
Excitation laser wavelength 364 nm, objective lens 100 × Immersion, N.A.1.2
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Sample data
SiO2/Si Raman spectrum and Raman image
Cross-hatch pattern
of strained SiGe film grown on Si substrate.
Image is obtained with Raman shift function.
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Raman shift
between the darkest "A" and
the brightest "B" spots of
the image
is 0.4 cm-1
only.
| Measurement
conditions: |
| Laser wavelength: |
365 nm |
| Objective lens: |
10×, N.A.0.95 |
| Grating: |
75 G/mm (Echelle) |
| Laser power: |
1.5 mW |
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Raman spectrum at points "A"
and "B".
Combination
of Echelle grating (hardware) and
spectral line fitting (software)
provides the unique ability for high
quality fine Raman shift (sample strain)
imaging.
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Latest news
New AFM-Raman combined system
New AFM-Raman combined system for simultanious Raman and topography imaging
Product "Nanofinder® FLEX" Catalog
Simple operation and low
cost with all the basic features of our top
of the line Nanofinder® 30
system.
Data "Strained Si Measurement" Update.
Spatial Resolution <130
nm,Strain 0.01% (0.1cm -1 shift),
High Sensitivity.
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