1) What We Measure

• Optical constants (refractive index n and extinction coefficient k) for thin films, coatings and bulk substrate over a wide wavelength range from 190nm to 30µm
• Accurate nondestructive thickness determination for thin films and thick coatings
• Alloy concentration determination for various thin films such as Ge in SiGe alloy, Al in AlGaN films
• Band gap determination for GaN, SiC, AlN, AlGaN, etc.
• Porosity measurement in low-K films
• Relative volume fraction determination for each component in nano-composite
• Physical thickness and optical properties for each layer in a multiple layer stack or periodic structure such as quantum well structure
• Thickness and optical properties uniformity information over as large as 300mm wafer sample
• Inhomogeneous film analysis in physical density or alloy concentration
• Optical properties for high-k films
• Nondestructive measurement for electrical conductivity of metal films, metallic compounds (such as WN, TiN, TaN, etc.), doped semiconductor epi layers (thickness can be also determined at the same time), other compound oxides such as ITO films
• Nondestructive measurement for doping concentration in doped semiconductors (active dopant! not total concentration as given by destructive SIMS analysis)
• Various Films in Photovoltaics (PV) applications, like CdS, CIGS, CdTe...
• Various Films on specially treated surfaces, like SiOx, SiNx on textured mono-Si surface, a-Si on glass substrates....
• Transparent Conductive Oxides (TCO), like ITO, FTO, IZO...

2) Spectrophotometry Measurement

• General reflection and transmission measurement over a spectrum range of 200nm to 20µm
• Diffuse reflection measurement
• Scatterrometry measurement
• Polarized transmission measurement
• Angular incidence reflection measurement from 0 to 85 degree (relative to normal)
• Microspectrophotometry measurement, sampling area as small as 2µm, for spectra (reflection, transmission, absorption) and thin film thickness

3) Surface roughness and profile analysis

• Surface roughness measurement
• 3D Surface profile analysis and plot

4) Fiber optics

• Special fiber characteristics analysis
• Fiber component characteristic analysis

Our analytical service provides you effective, nondestructive, accurate and cost effective measurement for thickness, refractive index, extinction coefficients and many other properties for film and coatings. Here are several points why you should try or use our service:

• Expertise in optical and semiconductor fields
• Nondestructive and non-contact
• Proven service reputation
• Strong team and partnered with other labs
• Turnaround as fast as you need
• Affordable and lowest cost
• Guaranteed quality

Again, why our service? Here is one of comments from our customer:

“As spectroscopic ellipsometry rapidly moved to the top of our list of required metrology for our development, Dr. Sun and his team at Ångstrom Sun Technologies provided our technical staff with strong technical support in the time leading up to our instrument purchase. When we decided to move ahead with acquisition of an Ångstrom Sun tool, Richard and his team met a very aggressive manufacturing and shipment schedule, which provided a tremendous benefit to us. And as we develop our own expertise in running the instrument, the Ångstrom Sun team continues to provide rapid, high-quality support for us. We’ve been very happy with our relationship with Ångstrom Sun and look forward to continuing to work with them.”

David Maloney, COO, Equity Solar, Inc.

• What wavelength range does your ellipsometer system cover?

             We cover the range from 190 nm to 30 µm.

• Is one measurement for whole range?

             No. There are several detectors and different light sources. Therefore, it needs at least two different measurements.

• What are the incident angles for ellipsometry measurement?

             They depend on your substrate and desired precision. The incident angles could vary from 30 to 89 degree automatically or manually.

• Do you use multiple angle measurement?

Yes or no. It depends on your specific samples.

• How long will it take for one measurement?

Measurement time varies from sample to sample and also model to model. For example, one full measurement at one incident angle or one mapping site only takes 1 second with our array based ellipsometer tool. While one measurement may take several minutes or even hours with scanned single element detector systems.

• How big samples can you handle?

TFProbe SE under standard configuration, can handle samples up to 450mm (18") in diameter.

• How small samples you can take?

We can take samples at a minimum size of 1mm in diameter.

• How about the sampling area on sample?

The parallel beam size is adjustable and it is between 1 to 5mm in diameter. For small samples, we use focused beam that has a beam size about 100µm only.

• Can you check uniformity information over a wafer?

Yes, we can run as many point measurements as you want over a maximum 450mm wafer.

• Will your tools come with turn-key operation?

Yes. There is full recipe setup so user can click button once to get final results.

• Can you measure Ge concentration in SiGe alloy?

Yes, we can measure Ge concentration in both strained and relaxed SiGe films as the same principle for Al concentration in AlGaN films. But some baselines have to be established first.

• Can you determine optical band gap for GaN, AlGaN, or SiC, etc.?

Yes, we do run band gap calculations based on the obtained optical constants from the ellipsometry modeling.

• Can you measure multiple layer stack?

Yes. A spectroscopic ellipsometry run at variable angles will help to get accurate results for each layer.

• Can you measure embedded ITO layer conductivity with ellipsometry technique?

Yes, with near infrared or middle infrared ellipsometer, Drude dispersion could be used to obtain electrical properties of conducting films.

• What materials ellipsometer can work with?

Almost all materials can be characterized with ellipsometry, such as Metals, polymers, ceramics, glasses, semiconductors and their compounds, composites etc. However, to be able to determine their thickness, there is upper limit for measurable thickness with absorbing films if they are absorbing in the measurement wavelength range.

• How about application fields for ellipsometry?

Here is a partial list of application fields for ellipsometry:

1. Semiconductor Industry:
   • Photoresist
   • Gate dielectrics
   • Semiconductors and their alloys or compounds such as, SiGe, InGaAs
2. Photonics
   • Optical coatings
   • Semiconductor compounds
   • Functional films in Optical MEMS
3. Data Storage
   • Diamond-like carbon (DLC)
   • Magnetic films
4. Flat Panel Display (FPD)
   • Thin film transistors (TFT) stack
   • Conductive oxide: Indium Tin Oxide (ITO)
5. Photovoltaics (PV)
   • SiNx AR coatings
   • SiOx Barriers
   • CdS, CdTe, CIGS...
   • Transparent Conductive Oxides (TCO), like ITO, FTO, Doped ZnO....

• Any Advanced Applications for ellipsometry?

Yes. Here are some examples for advanced applications for ellipsometry.

1. Ultra-thin gate dielectric films
2. Porous structure
3. Deep trench profile
4. Graded structure
5. Composites
6. Corrosion & protection of metals and alloys
7. Real time process monitoring for deposition rates, etching rates, etc. 

• Other questions?

Please contact us.