ANALYTICS AND QUALITY ASSURANCE

F R A U N H O F E R I N S T I T U T E F O R S U R F A C E E N G I N E E R I N G A N D T H I N F I L M S I S T

What we offer

In the development of new materials and manufacturing

processes, for quality assurance in production as well as for

the clarification of damage claims, the availability of analysis

and testing methods is a decisive factor. The Fraunhofer Insti-

tute for Surface Engineering and Thin Films IST offers a wide

range of methods as well as extensive expertise in the field of

layer analysis and testing technology. With more than 2,500

investigative assignments within ten years for more than 380

customers, the Fraunhofer IST has acquired an extensive range

of experience in the processing of industry-relevant issues,

such as:

� Support of material and process development

� Quality assurance in production

� Failure analyses

� Development of customer-specific testing technology

1

1 Micrograph of a dot array by means of

confocal laser microscopy (CLM).

2 Laser-structured trench, taken with the

atomic force microscope (AFM).

3 CLM micrograph of vickers indentations

in a surface.

4 CLM micrograph of particles on a surface.

2

Our range of services

� Advice on optimal analysis and testing methods

� Contract work using the latest analysis and testing equipment

� Analysis of surfaces and coatings, including technical objects such as components, tools and all kinds of everyday objects

� Fast processing, also within 24 hours

� Documentation and electronic transmission of results

� Processing performed by experienced employees

� Access to the knowledge and expertise of all departments of the Fraunhofer IST

ANALYTICS UND QUALITY ASSURANCE

Analytics

� Scanning electron microscopy (SEM)

� Focused ion beam (FIB and STEM)

� Energy-dispersive X-ray spectroscopy (EDX)

� Electron probe microanalysis (EPMA / WDX)

� Secondary ion mass spectrometry (SIMS)

� X-ray photoelectron spectroscopy (XPS)

� Glow-discharge spectroscopy (GDOES)

� X-ray diffraction (XRD)

� X-ray reflectivity (XRR)

� Atomic force microscopy (AFM)

� Confocal laser microscopy (CLM)

Measurement and testing methods

for friction and wear

� Pin-on-disc (adhesive)

� Ball-cratering (abrasive)

� High-load tribometer

� High-temperature tribometer

� Impact test

� Taber Abraser test

� Microtribology

3 4

Optical characterization

� IR / visible / UV spectroscopy

� Raman spectroscopy

� Colorimetry

� Ellipsometry

� Scattered light (haze)

� I-V curve measurement

� Quantum yield measurement

� CPM measurement

Other analytical methods

� Film-thickness measurement

� Profilometry (2D, 3D)

� Optical microscopy (2D, 3D)

� Hardness and Young´s modulus (micro- and nano-hardness)

� Film adhesion (scratch and Rockwell tests)

� Surface energy (wetting properties)

� Corrosion testing

� Environmental testing

� Vibrating sample magnetometer (VSM)

� Photocatalytic measurement technology

OVERVIEW OF OUR EXAMINATION METHODS

Scanning electron microscopy – SEM

Scanning electron microscopy SEM allows the imaging of

surfaces, fractures or cross-sections with high resolution

(~ 2 – 5 nm) and high depth of field. It is a versatile tool which

makes it possible to move through the magnification range of

20 x to 200 000 x within seconds, to switch quickly from one

sample to another and to image non-conductive surfaces by

means of sputtering. In combination with X-ray spectroscopy

(EDX), the SEM is the ideal tool for damage analysis as it

combines microscopic visualization with local chemical

analysis. On fractures or cross-sections, it can be used for

precise determination of film thickness in the nanometer to

millimeter range. By means of various detectors (Inlens, SE,

BSE), different contrasts can be highlighted, e. g. element or

topography contrast.

Focused ion beam – FIB

With focused ion beam FIB, microscopic defects, small spot

correction, cracks or artificial microstructures can be examined

in the SEM, even under the surface, and the cause of defects

can be clarified. The finely focused ion beam allows the tar-

geted removal of sample material in SEM under visual control

with an accuracy of < 100 nm. This opens up a diverse range

of investigation possibilities.

Fields of application

� Cross-section preparation: Preparation of local cross-sec-tions, e. g. for target preparation of very small defects (see Fig. 5). Materials such as polymers, glass, diamond, hard metal, leather, textiles, wood, paper and porous materials can be processed.

� Tomography: Creation of serial cuts for three-dimensional capture of structures or microstructures below the surface.

� Lamella preparation and STEM: STEM images (scanning transmission electron microscopy) make the internal structure of a material visible at the cross-section with par-ticularly high resolution, e. g. by means of crystallographic orientation contrast (see Fig. 6). In addition, chemical anal-ysis (EDX) with a spatial resolution of only 5 nm is possible. Compared to conventional cross-sections, this means an improvement by a factor of 100.

� Lithography: Through targeted material removal, complex structures can be scribed into the surface with high resolution.

5 6 TiAgZn

ZnOx 45 nm

Ag 12 nm

SiNx 45 nm

Pt protective layer

5 FIB section in TaOx-SiOx multilayer with em-

bedded particle.

6 STEM image of a low-emissivity coating sys-

tem: ZnO / TiO2 / Ag / ZnO / SiN / glass. EDX

mapping of the low-emissivity coating sys-

tem reaches a resolution of approx. 5 nm.

7 EDX-Mapping of the elements Ti, W and Co

of 2 µm thick TiN-layer fractured edge on a

hard metal substrate (WC:Co).

8 Schematic diagram of the thin film meth-

od: Simultaneous determination of film

thickness and composition of thin multiple

layers by WDX.

TiO2 5 nm

5 µm

X-ray radiation

Layer 1Layer 2

Substrate

Electron beam

7 8

X-ray spectroscopy – EDX

Electron beam-excited X-ray spectroscopy with semiconductor

detector (EDX) is a qualitative and quantitative chemical

element analysis. Important advantages are:

� Measurability of all chemical elements except H, He, Li and Be

� Detection limit of around 0.1 wt.%

� High spatial and depth resolution of ~1 µm (partly 0.3 µm)

In combination with the imaging of the sample in the SEM,

EDX is the ideal tool e. g. for the analysis of unknown techni-

cal samples, for damage analysis or material examination. As

an example, Figure 7 shows a high-resolution 2-dimensional

element-distribution image of a TiN layer on hard metal.

X-ray spectroscopy – WDX / EPMA

In wavelength-dispersive X-ray spectroscopy (WDX), the X-ray

radiation is detected by means of five crystal spectrometers.

This has the following advantages:

� 10 x better energy resolution than EDX (see left figure)

� 10 x better detection limit of around 0.01 wt.%

� high absolute precision

It is therefore very suitable for quantitative analysis, also of

trace elements. By means of special evaluation algorithms,

WDX can also be used for the simultaneous and non-destruc-

tive determination of film thicknesses and the composition of

thin films < 500 – 1000 nm (see Fig. 8). This also applies in part

to multiple and ultra-thin films of only 1 – 10 nm. One example

is the determination of oxide film thicknesses.

TiCoW

Inte

nsity

[n]

Energy [keV]

4.2 4.4 4.6 4.8 5.0 5.2

EDX = 110 eV WDX = 10 eV

0

10000

20000

TiKα-Line energy resolution of EDX and WDX.

MO-DiskAl

GdTbFe

PC

Com

posi

tion

[at%

]

0 40

Distance from center [mm]

105 15 20 3525 30

dGd-Tb-Fe

Tb

GdFe

dAl

0

10

20

30

40

50

60

70

0

10

20

30

40

50

60

70

Thic

knes

s [n

m]

Simultaneous and location-dependent determination of film

thickness and composition of a Al/GdTbFe double layer on a

polycarbonate substrate.

1 µm

9 10

Secondary ion mass spectrometry – SIMS

In secondary ion mass spectrometry (SIMS), the sample surface

is removed layer-by-layer using an ion beam. A mass spec-

trometer enables the chemical characterization of the removed

material.

The advantages

� Quantitative concentration-depth profiles with a depth range from only a few nanometers up to more than 10 µm

� Chemical analysis of interfaces and surfaces

� Detection of trace elements with a very high degree of sensitivity (< 1 ppm)

� Detection of all elements (including hydrogen)

� Depth profiling even on technical objects such as compo-nents or tools

Calibrating the concentrations is a special challenge in

secondary ion mass spectrometry since, due to matrix effects,

raw intensities can vary by many orders of magnitude. This

problem is approached by applying the Cs+ cluster method

in combination with a pool of more than 300 different

calibration materials, which are used as matched calibration

standards. An extensive experience, in particular in the field

of tribological protective coatings (DLC, metal-DLC, nitrides,

carbides, etc.) and optical multi-layer systems with metallic

and oxidic films of only a few nanometers in thickness exists.

Applications are found in all areas of engineering, tool

manufacturing, the automotive industry and the glass-coating

industry as well as in the fields of decorative coatings and

consumer goods.

C Ti N Fe H

0

20

40

60

80

100

0 1 2 3 4 5Depth [µm]

Con

cent

ratio

n [%

]

SIMS depth profile of a TiCN coating with intermediate

layers.

0

20

40

60

80

100

0 20 40 60 80 100 120Depth [nm]

Con

cent

ratio

n [%

]

ZnOSiN

SnO2

ZnO

TiONSiO2

TiON Ag

N O Si TiZn Nb Ag Sn

SIMS depth profile of a low-E architectural glass coating.

13 14

X-ray diffraction – XRD

X-ray diffraction (XRD) is a versatile technique for investigating

the structure of crystalline materials. Advantages of XRD are

� the identification of crystallographic phases,

� the measurement of particle sizes (2 – 200 nm),

� the determination of the preferred grain orientations (texture) and

� the determination of residual stresses.

The investigation can be performed on both planar and

curved component surfaces. One field of specialty at the

Fraunhofer IST is the characterization of thin films (in the

micrometer to nanometer range).

11 12

9-10 SIMS.

11 XRD pole figures for (200), (220), (311) and (111)

lattice planes of an electroplated Ni coating.

12 Inverse pole figure of the Ni coating, calculated

from the orientation distribution function (ODF).

0

100

400

Intensity

Position [°2-theta]

20 30 40 50 60 70 80 90 100

Diffractograms of lead zirconate titanate coatings, deposited

with different process parameters, measured under grazing

incidence.

Angle of incidence (°)

Inte

nsity

0.2 0.6 1.0 1.4 1.8 2.2 2.6 3.0

0

1

10

100

1 000

10 000

100 000

1 000 000

10 000 000

Layer Density [g/cm3] Thickness [nm] Surface roughness [nm]

Ag 9.5 9.4 1.9

ZnO 4.6 18.9 1.1

SiO2 1.9 - 0.7

Reflectivity curve of an Ag-ZnO double-layer on glass. Deter-

mination of density, thickness and surface roughness.

X-ray reflectivity – XRR

By means of X-ray reflectivity (XRR), it is possible to measure

the coating thickness, density and interfacial surface rough-

ness of ultra-thin films and multiple layers on very smooth

substrates. Layer thicknesses of approx. 2 to 200 nm can be

measured. Substrates should preferably be glass or silicon

wafers. Accuracies of ~ 0.2 nm are achieved in layer-thickness

measurements. XRR is one of the few methods which permits

density measurement without the need for weighing, and

it also makes the roughness of “buried” internal interfaces

between layers accessible.

X-ray photoelectron spectroscopy – XPS

X-ray photoelectron spectroscopy is a chemical analysis tech-

nique with a high surface sensitivity and a signal depth of

only 5 – 10 nm. Excited by X ray irradiation, photoelectrons are

emitted by the sample. The kintetic energy of these photoelec-

trons allow conclusions to be drawn concerning the material

composition on the basis of element-specific energy levels (all

elements except H and He). The detection limit lies at around

0.1 wt.%, whilst the analysis accuracy is in the percentage

range. With this method, even monolayers or the slightest sur-

face impurities can be analyzed.

The surface of materials or coatings often has a different

composition than the base material due to reaction layers, ad-

sorbates or surface tension-driven processes. As an example:

In combination with ion beam-induced erosion (sputtering),

surface enrichments can be identified and depth profiles of

100 nm depth and more can be created.

XPS also offers the possibility of making statements regarding

binding states, oxidation states or the proportion of differing

binding partners, for example in polymers (e. g. CH2, =CH

and -CH2-O), as the chemical environment of an atom influ-

ences the energy levels of the electrons.

13

13 XPS unit.

14 Nanoindentor impression in polymer coating.

15 Micro-scratch in quartz glass.

900 850

0

2

4

6

380 360 340

Ag-3d

Inte

nsity

Bond energy [eV]

Ni-2p

5% Ni90% Ni

After deposition After sputtering

XPS spectra of a 50 nm Ni-Ag coating before and after

sputter erosion (approx. 30 nm) of the surface. The Ag is

concentrated at the surface.

294 292 290 288 286 284 2820

2000

4000

6000

8000

10000

12000

14000

cts

Bond energy [eV]

Bond partners:

-CH2 / = CH

-C(O)-O (ester group)

-CH2-O (ester group)

Satellite peak

C peak of an XPS measurement of a PET film. The different

bond partners of the carbon atoms result in a peak splitting.

14 15

Microtribology

The same device also facilitates friction and wear tests on a

micrometer scale. A conical diamond tip is laterally guided

over the surface under a defined load, and friction and wear

are thereby determined. Furthermore, scratch tests with an

increasing load (see diagram), oscillating tests at a constant

load and area wear tests are also possible. This technique

enables scratch and wear tests to be carried out even on very

thin coatings (thickness 5 – 500 nm), which is not possible with

conventional scratch or tribological tests.

Nanoindentation

Nanoindentation allows the local determination of hardness

and Young’s modulus for ultra-thin films (> 300 nm) with a

lateral resolution in the micrometer range and therefore also

enables local hardness measurements or hardness mappings

on inhomogeneous samples. Furthermore, creep or relaxation

tests can also be performed in order to characterize the visco-

elastic properties of polymer layers or the self-healing behavior

of scratches in paints.

-180

-160

-140

-120

-100

-80

-60

-40

-20

0

20

-7 -5 -3 -1 1 3 5 7Lateral displacement [µm]

Pene

trat

ion

dept

h [n

m]

0.1

0.12

0.14

0.16

0.18

0.2

0.22

0.24

0.26

0.28

0.3-360 0 360 720 1080 1440 1800 2160 2520 2880 3240 3600 3960

Load [µN]

Coe

ffici

ent

of f

rictio

n

Depth with load Friction coefficient

Scan after scratchingScan before scratching

Micro-scratch test with increasing load on AF45 glass.

Maximum load 3.6 mN.

2 400

10

20

30

6 8 10

H (G

Pa)

Distance [µm]

(a)

800 Å5 µm

Series of nanoindentations through a CrN precipitation in

nitrided steel.

16 CLM image of micro structured grating after

tribological test.

17 AFM image of a SQUID sensor.

18 Ball-cratering tester.

19 Scratch tester.

20 Scratch with cracking and detachments.

Confocal laser microscope – CLM

The confocal laser microscope allows three-dimensional op-

tical imaging of surfaces. The image is generated by moving

the very sharply defined focal plane vertically through the

object. The lateral resolution is in the range of 0.5 µm, whilst

the vertical resolution achieves a few nanometers. Within a

few minutes, the method provides quantitative information

concerning, amongst other things, surface topography, rough-

ness, step heights, gradient angles or particle sizes. Compared

to tactile profilometric methods, it is considerably faster and

can also image soft or unstable surfaces, such as polymers

or powders. To a certain extent, it is also possible to measure

through transparent topcoats.

Atomic force microscopy – AFM

The atomic force microscope (AFM) is suitable for higher reso-

lutions. Here, the surface is scanned with an ultra-fine tip and

a 3D image of the surface is generated. Lateral resolutions of

1 to 10 nm and vertical resolutions of less than 1 nm can be

achieved, which makes it possible to resolve monoatomic step

heights. The AFM is particularly suitable for the characteriza-

tion of extremely smooth surfaces. Material contrasts can be

visualized via friction microscopy or modulation techniques.

With the AFM, it is possible to measure not only roughness,

step heights or grain sizes but also more complex parameters

such as skewness, kurtosis, power spectral density, etc. With

the AFM device at the Fraunhofer IST, not only small samples

can be investigated but also objects of up to 15 cm in diame-

ter and 3 cm in thickness.

16 17

00 50

Distance [µm]

Hei

ght

[µm

]

100 150

10

20

Height profile of a dot array (see page 2, figure 1).

18 20

Scratch test

The scratch test is used for determining the adhesion between

the coating and the base material. A diamond stylus is thereby

pulled with an increasing load over the coating system.

The resulting scratch is then optically evaluated. During

scratch testing, various coating flaws, such as cracking and

spalling, can be observed. A microscopic examination permits

analysis of e. g. film detachment. As a measure of the coating

adhesion, the critical load is determined at which the first

signs of delamination are noted. In addition, frictional force

and acoustic emissions are recorded during the measurement

process; these are useful in the interpretation of the results.

The method correspond to ISO 20502 and ASTM C1624.

Ball-cratering test

With the ball-cratering test, the wear resistance of coatings

and surfaces can be measured precisely. An abrasive slurry is

drip-fed onto a rotating steel ball which presses against the

sample, thereby grinding a crater (hemisphere) into the coat-

ing under investigation. The wear coefficient can be calculated

from the volume of the crater. This method is suitable for

testing coatings with a layer thickness ≥ 1 µm. Abrasion wear

reacts very sensitively to changes in the coating composition

and structure and can, for this reason, be used on the produc-

tion line as a characteristic for evaluating the coating quality

corresponding to EN ISO 26423.

19

Normal force [N] Acoustic emission [%]

Depth of penetration [µm] Coefficient of friction

Distance [mm]

50

40

30

20

10

0

0

6

12

18

24

30

0.2

0.1

1 10 20 30 40 50

0 1 2 3 4 5

100 %

80 %

60 %

40 %

20 %

0 %

Scratch test on DLC on steel. Critical load at 35 N.

Rate

of

wea

r [m

3 m-1N

-110

-15

]

Number of measurements

DLCTiNSteel 100 Cr6

500

1

10

100

10 15 20

Results of ball-cratering testing.

Abrasion coefficients of steel and hard coatings.

21 Rockwell test.

22 Principle of the Taber Abraser test.

23 Pin-on-disc tester.

24 Impact tester showing damage to a coated

piston ring.

21 22

Rockwell test

One method for determining the adhesive strength of

coatings is the Rockwell indentation test. This method has

been an established test procedure in industry and research

for many years (DIN 4856, ISO 26443). On account of its

simple handling and rapid implementation, the test is very

suitable for reliably revealing fluctuations in coating adhesion.

A conventional hardness test in accordance with Rockwell-C

is hereby performed with a conical indentation body. The

hardness indentations are examined under a light microscope

and categorized into adhesive strength classes (HF1 to HF6)

according to the size and quantity of the resulting layer spall-

ing. A substrate hardness of > 54 HRC is a prerequisite.

Taber Abraser test

Resistance to abrasive wear is an important mechanical

property of surfaces. The Taber Abraser test is a widely used

method for determining abrasion resistance, which is defined

in numerous standards (DIN52347, DIN7784, ASTM D4060,

ASTM D1044, ISO9352). The test can be applied for metals,

ceramics, rubber, paper, leather and textile fabrics as well as

for paints and other types of surface coatings. The instrument

is used both in research and development and in production

and quality control. The abrasive wear is generated by two

rough friction rollers, which are pressed onto the rotating test

specimen with a defined force. Possibilities enabling a quanti-

tative evaluation of the wear resistance include the gravimetric

determination of the removed material or the photographic

documentation of the strength of the abrasion.

Exemplary results of a Rockwell test: good adhesive strength

(left), medium adhesive strength (middle), bad adhesive

strength (right).

Revolutions [R/min]

Mas

s lo

ss [m

g]

0

A

B

0

10

20

30

40

50

60

70

2000 4000 6000 8000 10000

Taber test on two different steel types A and B.

Loss of mass depending on test duration.

Tribometers

Tribometers are utilized to investigate the friction behavior

of material pairings. A steel or carbide ball is pressed with

a defined normal force against a disc-shaped, rotating test

specimen (pin-on-disc). The coefficient of friction is calculated

from the frictional force and normal force. Tribological tests

are used to determine low-friction and wear-resistant material

pairings for technical movement systems.

The Fraunhofer IST has special high-temperature tribometers

for test temperatures of up to 1000 °C as well as high-load

tribometers with normal forces in the range of 10 to 1000 N.

Investigations using liquid lubricants are also possible.

23 24

Impact test

Coatings are increasingly used where the strength of technical

components is no longer sufficient. The increasing demands

on technical components result from higher temperatures,

increased operating pressures and longer service intervals.

The fatigue behavior and the adhesion of a coating are key

parameters for ensuring its functional reliability. With the im-

pact tester available at the Fraunhofer IST, statements can be

made concerning the fatigue strength of coating systems. A

firmly clamped ball hammers on the test specimen with forces

of up to 5 kN and a frequency of approx. 50 Hz. Tests with up

to one million cycles can be performed. This dynamic loading

can damage the material. The damage pattern (deformation,

layer detachment or cracks) is assessed visually and service-life

characteristics can be specified for this type of stress.

Change of the damage pattern after impact test at 200 N,

400 N and 600 N.

0

0.4

0.2

0.6

0.8

1.0

Coe

ffici

ent

of f

rictio

n [µ

]

DLCTiNSteel 100 Cr6

Coefficient of friction of steel and hard coatings against a

steel ball.

25 26

Photocatalytic air purification

Various commercially available products for photocatalytic air

purification can be used to clean the indoor air in rooms or to

remove gaseous pollutants such as nitrogen oxides from the

environment. The Fraunhofer IST has the analytical equipment

necessary for investigating the performance of photocatalytic

active materials. With this, it is possible to evaluate the respec-

tive materials and products comparatively.

At the Fraunhofer IST, tests are carried out in accordance with

ISO 22197-1 to -4, CEN/TS 16980-1 and DIN 19279 for the

pollutants NO, NO2, C2H4O, C7H8 and HCHO. Furthermore, as

an accredited testing laboratory of the German Federation for

Applied Photocatalysis (FAP), the Fraunhofer IST is authorized

to test and certify products in accordance with the “Freiwil-

ligen Selbstverpflichtung der Hersteller von photokatalytisch

aktiven Produkten” (Voluntary commitment of manufacturers

of photocatalytically active products).

Photocatalytic self-cleaning

Photocatalytic materials with self-cleaning properties are

applied in order to prevent the fogging or fouling of surfaces

and to completely decompose organic soiling to form water

and carbon dioxide (CO2). Photocatalysis thereby completely

forgoes the use of additional chemical substances and is there-

fore one of the most environmentally friendly and sustainable

technologies.

The Fraunhofer IST offers testing of the self-cleaning behavior

of coated glass surfaces by means of the so-called “dirt

test” (DIN EN 1096-5), the investigation of methylene blue

degradation (DIN 52980 and ISO 10678) as well as semi-quan-

titative test methods in accordance with e. g. ISO 27448 and

ISO 21066. In addition, the institute is able to verify, amongst

other things, the photocatalytic degradation of dyes and fatty

acids by means of customer-specific test methods.

Con

cent

ratio

n [p

pm] 1,2

1,0

0,8

0,6

0,4

0,2

0,00 50 100 150 200 250

Time [min]

NO NOx NO2

Test result of photocatalytic deposition velocity of NO

according to DIN 19279.

Con

cent

ratio

n [µ

mol

]

11.0

10.0

9.0

8.0

7.00 30 60 90 120 150 180

Time [min]

Irradiated sample

Reference in dark

Linear range

Photocatalytic decomposition of methylene blue according

to DIN 52980 or ISO 10678.

25 Measuring station to identify air purification

capability of photocatalytic materials.

26 Measuring station to identify photocatalytic ac-

tivities by depletion of methylene.

27 Measurement of contact angle.

28 FTIR measurement by micro ATRs on plastic foil.

Contact angle and surface energy

The wetting properties of material surfaces are important pa-

rameters which allow statements to be made concerning the

purity, adhesiveness, printability and fluid adhesion of a solid.

They can be determined by measuring the contact angle.

The contact angle of several liquids allows the determination

of the polar and non-polar proportions of the surface energy.

The hysteresis of the advancing and retreating contact angle

provides information regarding inhomogeneities or rough-

ness of the surface. The contact angle is a central measured

variable wherever the intensity of the phase contact between

liquid and solid materials is to be controlled or evaluated, e. g.

in painting, cleaning, printing, hydrophobic or hydrophilic

coating, bonding, and dispersion.

27 28

FTIR and Raman spectroscopy

FTIR spectroscopy (Fourier transform infrared spectroscopy) is a

special method of infrared spectroscopy. By means of infrared

radiation, molecular vibrations are induced, which become

visible in the spectrum through absorption. The method serves

the structural resolution of, for example, chemical compounds,

materials and coatings. Special features include:

� Characteristic absorption bands through absorption of elec-tromagnetic radiation (induced or variable dipole moment)

� High flexibility of the measuring set-ups (transmission, reflection, attenuated total reflection ATR, FTIR microscopy)

� Short measuring times

� Layer analysis < 100 nm film thickness is possible

In addition to FTIR spectroscopy, Raman spectroscopy can be

applied. With this technique, the sample is irradiated with

monochromatic light (532 nm, 633 nm or 785 nm) and alter-

ations in polarizability are induced via rotation or oscillation of

the molecule.

Con

tact

ang

le [°

]

Surf

ace

ener

gy [m

N/m

]

140

120

100

80

60

40

20

0

70

60

50

40

30

20

10

0

PTFE

F Si:O

Si Cr

Ti B W N Oa-C

:H

disp

ers

pola

r

Variants of a-C:H:X-films

Abs

orpt

ion

[-]

0.06

0.04

0.02

0.00

Wave count [cm-1]

3700 3200 2700 17002200 1200 700

FTIR-ATR-spectra of plasma-polymerized NiPAAm copolymer

on polypropylene.

CONTACTFraunhofer Institute for Surface

Engineering and Thin Films IST

Bienroder Weg 54 E

38108 Braunschweig

Dr. Kirsten Schiffmann

Head of the Department

Analytics and Quality Assurance

Telephone +49 531 2155-577

kirsten.schiffmann@ist.fraunhofer.de

www.ist.fraunhofer.de

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20

05

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