Polarization modulated ellipsometry. Final Report

Technical Report · Tue Jul 01 04:00:00 EDT 1986

OSTI ID:5011862

Lauer, J L; Marxer, N

For the investigation of the composition and thickness of thin nonuniform films on bearing and other tribological surfaces an automated ellipsometer was built, which is extremely sensitive to relative changes in thickness and composition of surface films. These changes can be seen by scanning across the surface with 20 micrometer lateral resolution. By measuring at different angles of incidence one can determine the film thickness and identify the material of the film by its complex index of refraction. For the analysis of organic layers on top of several metallic layers it was necessary to develop mathematical procedures to increase the absolute precision of the instrument. The ellipsometer is described in detail, and the precision is discussed. The actual performance of the ellipsometer was tested on three experiments. In the first one the composition and thickness of patches of an oxide film inside a wear track were determined. In the second the thickness of a carbon overcoat sputtered on a computer disk was measured: the carbon was identified as graphitic and of random orientation. In the third thickness of silicon oxide on top of a silicon substrate was found. Important features of this apparatus are: (1) accurate settings of the polarization stages and the angle of incidence (both automated); (2) high precision in the determination of the ellipsometric parameters without calibration prior to an experiment; and (3) very accurate scanning modes with high spatial resolution.

• Research Organization: Rensselaer Polytechnic Inst., Troy, NY (USA)
• OSTI ID: 5011862
• Report Number(s): N-86-26599; NASA-CR-177264
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420000 -- Engineering
440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
ACCURACY
CARBON
CHALCOGENIDES
COMPUTERIZED SIMULATION
DIMENSIONS
ELEMENTS
ELLIPSOMETERS
FILMS
LUBRICANTS
MEASURING INSTRUMENTS
NONMETALS
OPTICAL PROPERTIES
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLARIMETERS
REFRACTIVITY
RESOLUTION
SILICON COMPOUNDS
SILICON OXIDES
SIMULATION
SPATIAL RESOLUTION
THICKNESS
THIN FILMS
TRIBOLOGY