Two-channel spectroscopic polarization modulation ellipsometry: A new technique for the analysis of thin SiO₂ films

Conference · Thu Sep 05 00:00:00 EDT 2002 · Thin Solid Films

DOI:https://doi.org/10.1016/0040-6090(91)90438-4· OSTI ID:6071148

Jellison, Jr., G. E. ^[1]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

A new spectroscopic ellipsometer is described, where the incoming light is dynamically polarized using a photoelastic modulator, and the reflected light is separated into orthogonally polarized beams using a Wollaston prism. Both beams are detected using photomultiplier tubes whose bias voltage is dynamically controlled for constant d.c. All three of the associated ellipsometry parameters (N = cos 2ψ, S = sin 2ψ sinΔ, C= sin 2ψcosΔ) can be determined simultaneously in a single scan s40–840 – nm or 5.16–147 eV). This instrument was used to study the optical properties of thin SiO₂ films from 3 to 325 nm in thickness. Using a biased estimator fitting technique, the raw ellipsometric data can be fitted to an air-SiO₂-interface-Si model, where the optical functions of the SiO₂ layer and the interface region are approximated using one-term Sellmeier approximation Sellmeier approximation, and a 50% SiO₂ Bruggeman effective medium approximation respectively. The refractive index of the SiO₂ layer is dependent on film thickness, increasing with decreasing film thickness, but always being greater than that of fused quartz. The thickness of the interfacial region increases with increasing film thickness, being less than 0.2 nm for film thickness less than 20 nm.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6071148
• Report Number(s): CONF-9104187-1; ON: DE91010131
• Journal Information: Thin Solid Films, Vol. 206, Issue 1-2; Conference: International Conference on Metallurgical Coatings and Thin Films, San Diego, CA (United States), 22-26 Apr 1991; ISSN 0040-6090
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
47 OTHER INSTRUMENTATION
ELLIPSOMETRY
USES
SILICON OXIDES
OPTICAL PROPERTIES
DATA PROCESSING
ELLIPSOMETERS
EXPERIMENTAL DATA
INTERFACES
POLARIZATION
REFRACTIVITY
SILICON
SUBSTRATES
THICKNESS
THIN FILMS
CHALCOGENIDES
DATA
DIMENSIONS
ELEMENTS
FILMS
INFORMATION
MEASURING INSTRUMENTS
MEASURING METHODS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLARIMETERS
PROCESSING
SEMIMETALS
SILICON COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties
440600 - Optical Instrumentation- (1990-)