Ellipsometers for Semiconductors

iSMART Research Group and J. A. Woollam IR-Vase II Case Study and Bespoke Ellipsometry Measurements for the Semiconductor Market

Learn more about J A Woollam Ellipsometers

CASE STUDY:

iSMART Research Group and Woollam IR-Vase II Quantum Design UK and Ireland (QDUKI), in collaboration with the Medical Technologies Innovation Facility (MTIF) and Nottingham Trent University are proud to present this case study from the iSMART (innovation in Surfaces, Materials and Related Technologies) research group, led by Dr. Nikolaos Kalfagiannis and co-workers from Université de Poitiers, Sheffield Hallam University and the University of Nottingham.

Dr Nikolaos Kalfagiannis is interested in light-matter interactions and optical properties of materials and thin films both from experimental (spectroscopic ellipsometry) and computational point of view (finite-difference time-domain method).

He is an expert in Spectroscopic Ellipsometry, a sophisticated optical technique that provides the complex refractive index of materials and thin films (in the latter case it also provides information about the thickness with Angstrom resolution). NTU is equipped with a unique IR Spectroscopic Ellipsometer (240–8000 cm-1 / 0.03 – 0.99 eV).

Dr. Kalfagiannis has been a speaker at the QDUKI Spectroscopic Ellipsometry Workshops and Courses in recent years.

The iSMART group have focused their research around the optical and electronic properties of materials and thin films for nano-photonic and electronic applications, specifically metal-oxides.

QDUKI supplied the J A Woollam Infrared Variable Angle Spectroscopic Ellipsometer (IR VASE-II) capable of providing the optical constants of materials in the extended spectral range from 1.6 – 40 microns.

Indeed, QDUKI and MTIF have entered into a partnership to provide access to potential users to view and measure trial samples on, the J. A. Woollam IR VASE II Spectroscopic Ellipsometer on an ad hoc contract basis.

Dr. Kalfagiannis’ teaching duties include: Optics & Semiconductors Research Methodology & Ethics

Condensed Matter Physics Current Topics in Physics, BSc and MSc research project

Spectroscopic ellipsometry (SE) is a highly sophisticated and non-destructive metrology

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tool for determining the optical constants of materials. iSMART is equipped with a J. A. Woollam Infrared Variable Angle Spectroscopic Ellipsometer (IR VASE II), capable of providing the optical constants of materials in the extended spectral range from 1.6 – 40 microns.

Only two ellipsometers of this type currently exist in the whole of the UK, with one such system being located at MTIF which is available

In the iSMART (innovation in Surfaces, MAterials and Related Technologies) research group (embedded within the Medical Technologies Innovation Facility – MTIF, based in Nottingham, UK) we focus our research interest around the optical and electronic properties of materials and thin films for nanophotonic and electronic applications.

for contract development work and academic partnership for all UK industry and any Research institutes.

One such example of a family of materials related to both applications, mentioned above, are the metal-oxides. Metal oxides have emerged as promising material candidates in various

electronic

and

optoelectronic

applications offering unique advantages such as high mobility, wide bandgap (transparent in

The IR VASE II was supplied by Quantum Design

the visible range), and the ability to be

UK

controllably doped. Importantly, in iSMART we

representatives of J. A. Woollam inc. Quantum

have developed routes to different scalable

Design UK and Ireland Ltd. and MTIF have entered

deposition techniques for such materials (from

into a partnership to provide access to potential

wet chemistry methods to vacuum deposition techniques).

and

Ireland

Ltd.

who

are

the

official

users to view, and measure trial samples on, the J. A. Woollam IR VASE II Spectroscopic Ellipsometer on an ad hoc contract basis.

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Our partnership with The University of Nottingham (contact person: Dr. Christopher Mellor) allows for this spectral range to be extended further, using a J.A. Woollam M-2000DI spectroscopic ellipsometer, to include the near infrared, visible and ultraviolet wavelengths (1.69 – 0.193 microns). This combined capability, offers one of the widest spectral ranges available world-wide (0.19 – 40 microns).

By extracting the exact optical constants, we also enable the determination of material properties such as charge transport (mobility, doping concentration, resistivity), lattice vibration (phonon absorption) and band structure (via interband transitions and band gaps).

These fundamental properties of semiconducting materials are key parameters for optoelectronic applications.

In a recent work, Dr. Nikolaos Kalfagiannis and

co-workers

from

Université

de

Characterise any semiconductor materials: resists, photomasks, SiON, ONO stacks, low-k dielectrics, high-k gates, SOI, SiGe, II-VI and III-V ternary and waternary compounds

J A Woollam IR VASE II Spectroscopic Ellipsometer Ellipsometer for thin films and bulk materials characterisation The IR-VASE® is the first and only spectroscopic ellipsometer to combine the chemical sensitivity of FTIR spectroscopy with thin film sensitivity of spectroscopic ellipsometry. The IR-VASE covers the wide spectral range from 1.7 to 30 microns (333 to 5900 wavenumbers).

Poitiers, Sheffield Hallam University and The University of Nottingham, employ SE in the extended spectral range (0.2 – 40 microns) and develop the methodology for the accurate determination of the free carrier transport properties of transparent conductive

oxides

and

discriminate

between

the

different

scattering

mechanisms (grain boundary scattering, inter-grain scattering and ionised impurity scattering) in an effort to clarify the conduction mechanisms of such materials and define their range of application.

Want to learn more about Ellipsometry?

Contact our Technical Director: Dr. Shayz Ikram Telephone (01372) 378822 Email shayz@qd-uki.co.uk

J A Woollam M2000 Spectroscopic Ellipsometer Ellipsometer for thin film characterisation The M-2000 line of spectroscopic ellipsometers is engineered to meet the diverse demands of thin film characterisation. An advanced optical design, wide spectral range, and fast data acquisition combine in an extremely powerful and versatile tool.

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WWW.QD-UKI.CO.UK

Seeking to better understand the optical and electronic properties of materials or thin films for nanophotonic or electronic applications?

The partnership agreement between QDUKI and the Medical Technology Innovation Facility, affords customers the ability to view and utilise the JA Woollam IR VASE II Spectroscopic Ellipsometer.

Indeed, this is only one of two such instruments in the UK and the only one now made available to customers in the UK in this way. The nature of Ellipsometry (relatively fast and non-destructive) makes it ideal for diagnostics in several sectors such as semiconductor devices, photovoltaics, nano-photonics, flat panel displays, optical coating stacks,

construction

materials,

biological

and

medical coatings, protective layers as well as realtime quality control.

A variety of assistive technologies for materials deposition,

including

physical

and

chemical

deposition techniques, such as RF magnetron sputtering, atomic layer deposition and thermal evaporation of nano-engineered coatings and thin films. These are applicable across a broad range of industrial applications such as, optical coatings, plasmonic thin films, SERS sensors and large-area electronic devices.

MTIF – with a strong academic pedigree and expertise in nanofabrication – can conduct such analysis on your behalf offering a bespoke and individualised service. Please reach out to discuss your needs today.

Want to learn more about Ellipsometry?