Spectroscopic ellipsometer based on direct measurement of polarization ellipticity

Journal Article · Mon Jun 20 04:00:00 EDT 2011 · Applied Optics

DOI:https://doi.org/10.1364/AO.50.002973· OSTI ID:22036632

Watkins, Lionel R

A polarizer-sample-Wollaston prism analyzer ellipsometer is described in which the ellipsometric angles {psi} and {Delta} are determined by direct measurement of the elliptically polarized light reflected from the sample. With the Wollaston prism initially set to transmit p- and s-polarized light, the azimuthal angle P of the polarizer is adjusted until the two beams have equal intensity. This condition yields {psi}={+-}P and ensures that the reflected elliptically polarized light has an azimuthal angle of {+-}45 deg. and maximum ellipticity. Rotating the Wollaston prism through 45 deg. and adjusting the analyzer azimuth until the two beams again have equal intensity yields the ellipticity that allows {Delta} to be determined via a simple linear relationship. The errors produced by nonideal components are analyzed. We show that the polarizer dominates these errors but that for most practical purposes, the error in {psi} is negligible and the error in {Delta} may be corrected exactly. A native oxide layer on a silicon substrate was measured at a single wavelength and multiple angles of incidence and spectroscopically at a single angle of incidence. The best fit film thicknesses obtained were in excellent agreement with those determined using a traditional null ellipsometer.

• OSTI ID: 22036632
• Journal Information: Applied Optics, Journal Name: Applied Optics Journal Issue: 18 Vol. 50; ISSN 0003-6935; ISSN APOPAI
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BEAMS
ELLIPSOMETERS
ERRORS
FILMS
INCIDENCE ANGLE
LAYERS
OXIDES
POLARIZATION
PRISMS
SUBSTRATES
THICKNESS
VISIBLE RADIATION
WAVELENGTHS