Description
To the point
Determining the thermo-physical properties of materials and optimizing heat flows in end products is becoming increasingly important for many industrial applications.
For this reason, the flash method has become the most commonly used technique for measuring the temperature and thermal conductivity of various solids, powders and liquids in recent decades.
In the age of nanotechnology, more and more industries and users now require precise measurement data for very thin layers.
The semiconductor industry with typical products such as light-emitting diodes (LEDs), phase-change memories or flat screens has the greatest demand.
Several layers of different materials are often deposited on a substrate in order to create a component with a specific function.
Since the physical properties of thin films usually differ from those of a solid material, their characterization is essential for the design and optimization of thermal management.
Based on the proven laser flash technology, the Linseis Laserflash for Thin Films (TF-LFA) now offers a whole range of new possibilities for analyzing the material data of thin films with a thickness of 10 nm to 20 µm.
Thermal properties:
- Thermal conductivity
- Volumetric heat capacity
- Thermal diffusivity
- Thermal efficiency
- Thermal limit conductivity
Thin films:
Thin films are materials with a thickness of nanometers to micrometers that are applied to surfaces.
Their thermophysical properties differ considerably from those of bulk materials and depend on thickness and temperature.
Thin films are generally used in semiconductors, LEDs, fuel cells and optical storage media.
Different types of thin films
- Thin film: layer from a few nm to µm
- Layers are grown on a special substrate
- Typical growth techniques are
- PVD (e.g. sputtering, thermal vaporization)
- CVD (PECVD, LPCVD, ALD)
- Drop casting, Spin coating & Printing
- Many different types of layers, including:
- Semiconductor layers (e.g. thermoelectric, sensors, transistors)
- Metallic layers (used as contacts)
- Thermal barrier coatings
- Optical coatings
Multilayer sample
Thin film
(e.g. semiconductor, metal, organic, oxide)
Substrates
(e.g. Si, Si3N4, Fused Silicia)
FDTR
Frequency Domain
FDTR is a non-contact method for characterizing the thermal properties of thin films in the frequency range using the effect of thermoreflectance to create a highly sensitive thermometer for measuring the surface temperature of the sample by monitoring the reflectivity.
A continuous wave laser (probe laser) with a wavelength of 532 nm is used for this purpose, while a harmonically modulated pump laser with a different wavelength (405 nm) is used.
Local heating leads to changes in reflectivity, and the phase delay between thermal excitation and detection is measured with a lock-in amplifier.
Modeling the response in the frequency domain with a diffusive heat transport model allows the determination of thermal conductivity, volumetric heat capacity, thermal diffusivity, thermal efficiency and thermal interface conductance.
A thin metallic transducer layer (60-70 nm thick) is applied to the surface of the samples to increase the temperature coefficient of reflection, dR/dT, and at the same time reduce the optical penetration depth into the material.
Advantages:
- Wider measuring range
- Easier handling
- Greater stability
- More precise results
- Possibility to measure the thermal contact resistance between two layers
- No more assumptions about heat capacity and density of thin sample layers
Comparison of FDTR and TDTR methods
Our advanced FDTR (Frequency-Domain Thermoreflectance) system offers significant advantages over the conventional TDTR (Time-Domain Thermoreflectance) method by optimizing the setup and increasing measurement stability.
The probe laser does not need to be adjusted: In contrast to the TDTR arrangement, where the probe laser has to be adjusted relative to the sample because the reflection changes slightly when the sample changes, our FDTR system eliminates this need.
Our system has an automatic focusing system that continuously adjusts the focus of the probe laser to any changes in the sample, thus ensuring optimum measurement conditions without manual intervention.
Aligned lasers: Thanks to the perfectly aligned lasers in our FDTR system, the probe laser beam does not need to be adjusted, resulting in easier sample set-up and more stable measurements.
Unique features
Comprehensive thermal characterization:
- Measurement of thermal conductivity,
heat capacity, thermal diffusivity and
thermal effusivity - Determination of the thermal contact
between two neighboring layers
Anisotropy function:
- Optional function for measuring the thermal
conductivity both in the direction of passage
(through the material) and in the plane
(perpendicular to the laser excitation)
Wide temperature range:
- The device can measure the thermal properties
of thin films at room temperature up to 500°C
Thermal imaging:
- With the optional sample
mapping function, the thermal
properties of the sample can be
tracked over a specific area or
points of the surface, ideal for
homogeneity tests
Automatic optimization and camera option:
- Automatic optimization of the laser beam
to improve the measurement results - Additional camera option that provides
visual information and facilitates the selection
of interesting spots on the sample surface
Measurement of thermal contact
resistances/conductive values:
- Measurement of the thermal
contact between two layers,
e.g. between sample and surface
or sample and transducer layer
Service hotline
+1 (609) 223 2040
+49 (0) 9287/880 0
Our service is available Monday to
Thursday from 8 am to 4 pm
and Friday from 8 am to 12 pm.
We are here for you!
Specifications
Black on white
MODEL | TF-LFA |
|---|---|
| Sample dimensions: | Any shape between 2mm x 2mm and 25mm x 25mm lateral size |
| Thin film samples: | 10nm up to 20μm* (depends on sample) |
| Temperature range: | RT, RT up to 200/500°C Sample holder for 4“ Wafer (only RT) |
| Measured properties: | Thermal conductivity Thermal diffusivity Thermal interface resistance Volumetric specific heat capacitiy Thermal effusivity |
| Options: | Anisotrophy: Measurement of cross-plane and in-plane thermal properties Sample mapping: Scanning multiple positions of the sample pointwise or clusterwise. Mapping area: 10 mm² Stepsize: 50 μm Camera: Allows the user to view the present sample surface and the position of the laser beams to record the actual measurement position. |
| Atmosphere: | inert, oxidizing or reducing vaccuum up to 10E-4mbar |
| Diffusivity measuring range: | 0.01mm2/s up to 1200mm2/s (depends on sample) |
| Pump laser: | CW Laser (405 nm, 300 mW, modulations frequency up to 200 MHz) |
| Probe laser: | CW Laser (532 nm, 25 mW) |
| Photodetector: | Si Avalanche Photodetector, active diameter: 0.2 mm, bandwidth: DC - 400MHz |
| Power supply: | AC 100V ~ 240V, 50/60 Hz, 1 kVA |
| Software: | Included. Software package using multi-layer analysis for calculation of thermophysical properties |
| *Actual thickness range depends on sample | |
Data sheet
Software
Making values visible and comparable
All LINSEIS thermoanalytical devices are PC-controlled, the individual software modules run exclusively under Microsoft® Windows® operating systems.
The complete software consists of 3 modules: temperature control, data acquisition and data evaluation.
As with other thermoanalytical experiments, the LINSEIS software offers all the essential functions for preparing, carrying out and evaluating the measurements.
Thanks to our specialists and application experts, LINSEIS has succeeded in developing this easy-to-understand and highly practical software.
General software
- Fully compatible with MS® Windows™
- Data security in the event of a power failure
- Evaluation of the current measurement
- Comparison of the curves
- Storage and export of evaluations
- Export and import of ASCII data
- Data export to MS Excel
Evaluation software
- Determination of the contact resistance
- Multi-layer heat transfer model for simultaneous determination of thermal conductivity, thermal diffusivity, thermal efficiency and volumetric heat capacity
- Checking the feasibility of the
- Measurement
Sensitivity diagram
Measuring software
- Simple and user-friendly parameter input for temperature control, gas control, etc.
- Software automatically displays a corrected measurement according to the pulse
- Fully automatic measurement
Applications
Application example: SiO2 thin film 504 nm
Thin film glass layers out of pure silicon dioxide (Quartz) are frequently used in semiconductor and electronic industries as protective layer or thermo or electronical insulation layers. In this example SiO2 layer was investigated using the Linseis TF-LFA device to fully characterize its thermal properties.
Aluminum nitride AIN 200 nm
Application example: Aluminum nitride AIN
AlN is frequently used as thermal insulation layer or electronical insulation layer in sensors or microelectronics. Its thermal properties depending on layer thickness were investigated by TF-LFA in this application.
Aluminum nitride AIN 800 nm
Aluminum nitride AIN 1600 nm
Well informed
