Genetic algorithm using independent component analysis in x-ray reflectivity curve fitting of periodic layer structures

Nonlinear fitness–space–structure adaptation and principal component analysis in genetic algorithms: an application to x-ray reflectivity analysis

Two novel genetic algorithms implementing principal component analysis and an adaptive nonlinear fitness–space–structure technique are presented and compared with conventional algorithms in x-ray reflectivity analysis. Principal component analysis based on Hessian or interparameter covariance matrices is used to rotate a coordinate frame. The nonlinear adaptation applies nonlinear estimates to ...

Novel Genetic Fitting Algorithms and Statistical Error Analysis Methods for X-ray Reflectivity Analysis

Investigation of dip coated ZnO thin film : X - ray reflectivity and Fourier analysis

: In this study we fabricated Zinc Oxide thin film by sol-gel dip coating method on glass substrate. X-ray reflectivity (XRR) and its optimization have been used for characterization and extracting physical parameters of the film. Genetic Algorithm (GA) has been applied for this optimization process. Independent information was exploited from Fourier transform of Fresnel reflectivity normalized...

Fitness function and nonunique solutions in x-ray reflectivity curve fitting: crosserror between surface roughness and mass density

Nonunique solutions of the x-ray reflectivity (XRR) curve fitting problem were studied by modelling layer structures with neural networks and designing a fitness function to handle the nonidealities of measurements. Modelled atomic-layer-deposited aluminium oxide film structures were used in the simulations to calculate XRR curves based on Parratt’s formalism. This approach reduced the dimensio...

Determination of layer structure in Mo/Si multilayers using soft X-ray reflectivity

The soft X-ray reflectivity characterization of Mo/Si multilayer deposited by electron beam evaporation is discussed. The measurements are performed on Indus-1 synchrotron storage ring. The interdiffusion of two-layer materials in multilayer leads to the formation of interlayers. To understand the influence of interlayers and interfacial roughness on soft X-ray reflectivity profile, simulation ...