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Alfred Hofrichter

Publications and source records attributed to Alfred Hofrichter.

2 recordsLinked to original sources

Direct numerical inversion method for kinetic ellipsometric data. I. Presentation of the method and numerical evaluation.

A direct numerical inversion method for the determination of the refractive index and the thickness of the outermost layer of a thin transparent film on top of a multilayer has been developed. This method is based on a second-order Taylor decomposition of the coefficients of the Abelès matrices of the newly grown layer. The variations of the real-time spectroscopic ellipsometry data are expressed as polynomial fuctions depending on the dielectric constant and the thickness of the newly grown layer. The method is fast, capable of single-wavelength and multiwavelength inversion of continuous as well as discontinuous-index profiles, and can be adapted to many different polarimetric instruments.

Journal Article↗

Direct numerical inversion method for kinetic ellipsometric data. II. Implementation and experimental verification.

A direct numerical inversion method is applied to the monitoring of thin-film growth. Several improvements of the method, including a correction for weakly absorbing materials, are presented. The method has been successfully applied to the inversion of the growth of constant-refractive-index layers andused for the process calibration of plasma-enhanced chemical vapor deposition of silicon oxynitrides. The validity of this calibration has been successfully tested on a linear index gradient and quintic matching layer between a polycarbonate substrate and a scratch-resistant coating.

Journal Article↗