SiOx layer on glass

SiOx layer on glass

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SiOx layer on glass: Demonstrating efficient fitting techniques

Configuration file
../demo/scout/siox_on_glass/siox_on_glass_master.sc2

Main window

What do you see?
The bottom part of the window shows transmittance and reflectance spectra recorded with our FIRST spectrometer. The investigated system is a single SiOx layer deposited on a microscope slide. For various oxygen concentrations the parameters of an OJL interband transition model have been determined. Then a master model for optical constants was introduced to control all parameters by a single one, namely the oxygen content of the SiOx layer. The determination of the oxygen content and the layer thickness is the goal of the analysis.
The values of both parameters can be modified by the two sliders in the upper left corner of the window.

What can you do?

·	Play with both sliders to investigate the influence of each parameter on the spectra.

·	Starting with obviously wrong parameter values, try to optimize the fit manually by appropriate slider motions.

Now let SCOUT do the work. Set wrong values and press the 'Start' button. After a short time the fit finishes having found the best values of 4.0 and 432 nm, respectively. This is achieved by a combination of different fitting techniques. There are three phases of the fit: First various oxygen contents are tested on a grid of 20 values covering the full range of possible values between 1.0 and 7.0. Then the best thickness on a grid of 50 values between 50 and 1000 nm is determined. Taking the best 'pre-fit' results as starting values for the parameters, the downhill simplex method is started. This method is the standard optimization scheme used by SCOUT.