Ellipsometry Testing for Thin Film Thickness & Optical Properties
Ellipsometry is an optical technique commonly used for thin-film and surface property analysis by the reflection or transmission of polarized light. The change in polarization state is measured and correlated with material properties. Infinita Lab, USA, offers this test effectively and accurately.
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- Overview
- Scope, Applications, and Benefits
- Test Process
- Specifications
- Instrumentation
- Results and Deliverables
Overview
Ellipsometry is a non-destructive optical measurement technique that determines the thickness and optical constants (refractive index and extinction coefficient) of thin films by analysing the change in polarisation of reflected light. It is widely used in semiconductor manufacturing, optical coatings, and materials research.
Because ellipsometry is contactless and highly sensitive, it is ideal for characterising films ranging from a few angstroms to several micrometres in thickness without damaging the sample.
Scope, Applications, and Benefits
Scope
Ellipsometry evaluates:
- Film thickness (Å to µm range)
- Refractive index (n) and extinction coefficient (k)
- Complex dielectric functions
- Multi-layer film stack analysis
Applications
- Semiconductor gate oxide and dielectric layer characterisation
- Optical coating quality control
- Polymer and self-assembled monolayer thin-film analysis
- Solar cell and photovoltaic device characterisation
- Biological film and surface functionalization studies
Benefits
- Non-contact, non-destructive measurement
- Angstrom-level thickness sensitivity
- Simultaneous measurement of multiple optical parameters
- Applicable to opaque and transparent films
- Compatible with in-situ and ex-situ configurations
Test Process
Sample Mounting
The sample is positioned on the ellipsometer stage at a defined angle of incidence (typically 60°–75°).
1Light Polarization & Reflection
Polarized light is directed onto the film surface; the reflected beam's polarization state change is recorded.
2Model Fitting
An optical model is constructed and fitted to the measured Ψ/Δ data using regression analysis.
3Results Extraction
Film thickness, n, and k values are extracted from the best-fit model and compiled into the final report.
4Technical Specifications
| Parameter | Details |
|---|---|
| Applicable Materials | Semiconductors, oxides, polymers, metals, biological films |
| Thickness Range | ~1 Å to >100 µm |
| Wavelength Range | 190–2500 nm (spectroscopic) |
| Angle of Incidence | 45°–90° (variable) |
| Instrumentation | Spectroscopic ellipsometer |
Instrumentation Used for Testing
- Spectroscopic ellipsometer (single or variable angle)
- Motorised rotating analyser or compensator
- Light source (broadband Xe lamp or laser)
- CCD detector array
- Optical modelling and data fitting software
Results and Deliverables
- Film thickness values with uncertainty estimates
- Optical constants (n, k) as a function of wavelength
- Dielectric function spectra
- Multi-layer stack analysis results
- Comparative analysis and trend reports
Frequently Asked Questions
Ellipsometry can resolve films as thin as 1 Å (0.1 nm), making it highly suitable for monolayer and ultrathin film characterization.
Yes. For opaque films, ellipsometry determines the optical constants and can estimate surface roughness, even if transmission-based thickness measurement is not possible.
Minimal preparation is needed. The sample surface should be clean and flat. Rough or contaminated surfaces may require pre-cleaning to ensure accurate optical model fitting.
Single-wavelength ellipsometry uses one wavelength and is faster but less informative. Spectroscopic ellipsometry measures across a wavelength range, providing richer data for complex multi-layer or dispersive film analysis.
Yes, with an appropriate optical model, spectroscopic ellipsometry can resolve the individual thicknesses and optical constants of stacked multi-layer film systems.
Why Choose Infinita Lab for Advanced Materials Testing and Characterization?
At the core of this breadth is our network of 2,000+ accredited laboratories across the USA, offering access to over 10,000 testing methods and analytical services. From advanced materials characterization (SEM, TEM, RBS, XPS) to mechanical, chemical, environmental, biological, and standardized ASTM/ISO-compliant testing, we deliver unmatched flexibility, specialization, and scale. You are never limited by geography, facility, or methodology — Infinita Lab connects you to the right expertise and testing solution, every time.
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