Optical scattering from oxidized metals. 2: Model verification for oxidized copper

Area of Science:

• Materials Science
• Surface Science
• Optical Physics

Background:

• Oxidized metal films are crucial in various applications.
• Understanding the optical properties requires knowledge of surface and interface characteristics.
• Diffuse reflectance spectroscopy is a key technique for characterizing these films.

Purpose of the Study:

• To apply and validate a model for calculating diffuse reflectance spectra of oxidized metals.
• To independently determine the root-mean-square (rms) roughness of air-oxide and oxide-metal interfaces.
• To compare model-derived roughness values with experimental measurements.

Main Methods:

• Application of a diffuse reflectance spectra calculation model to thermally oxidized copper films.
• Fitting the model to experimental spectra to extract interface roughness parameters.
• Comparison of model-derived rms roughness with stylus profiling and total integrated scattering measurements.

Main Results:

• The model accurately reproduces the spectral structure of experimental diffuse reflectance data.
• Air-oxide interface roughness dominates scattering at shorter wavelengths, while oxide-metal roughness dominates at longer wavelengths.
• Independently determined rms roughness values show good agreement across different measurement techniques.

Conclusions:

• The developed model is effective for analyzing diffuse reflectance spectra of oxidized metals.
• The model allows for independent determination of air-oxide and oxide-metal interface roughness.
• The findings validate the model's applicability and provide insights into scattering mechanisms in oxidized metal films.