Thin Film Thickness¶

Measuring thicknesses of thin-films optically is one of the strengths of the Ellipsometry measurement technique. Exploiting interference phenomena and the different phases in reflection of polarized light gives rise to a very sensitive measurement technique.

The LayeredMediaSolver in JCMsuite can be used to simulate the reflectivity of these thin films. In this example we model a 50nm thin film with material properities similar to silicon dioxide on a high-refractive index substrate.

project.jcmp [ASCII]

PostProcess {
  LayeredMediaSolver {
    OutputFileName = "result.jcm"
     LayerThickness = 5e-08
     RelPermittivityInLayers=[(1, 0); (2.24999996, -0.0006); (12.25, 0);]
     Lambda0 = [2e-07 : 5e-10 : 1e-06]
     IncidenceAngle = [0 : 2 : 20]
  }
}

The solver requires the definition of the thicknes of the layer in the vector LayerThickness and their material properties via the RelPermittivityInLayers. Here, the first and last entry are used to describe the relative permittivity on the incident and outgoing side. A definition of multiple vacuum wavelengths $\lambda_0$ in Lambda0 and $\theta$ angles in IncidenceAngle is allowed and yields the reflection spectrum in one simulation run.

The result is stored in the file result.jcm provided as the OutputFileName. It yields reflectivity and transmission values for both polarizations and for every combinations of $\lambda_0$ and $\theta$ stored in the output table.

These input parameters of the ellipsometry experiment and the required construction of the input for the project.jcmpt template are set in the run_project.m script. The reflection result is calculated and plotted as well.

Calculated reflectivity and the ellipsometric angle $\Delta$ at 18 degree incidence.¶