Influence of the light incidence angle on the precision of generalized magneto-optical ellipsometry

• A brief review of generalized magneto-optical ellipsometry is presented.
• We calculate the propagation of uncertainties on the magneto-optical constants.
• Decreasing incidence angle increases the uncertainty propagation.
• We perform measurements on bulk cobalt films which confirm our predictions.

We study theoretically and experimentally the influence of the light incidence angle φ0 on the precision of generalized magneto-optical ellipsometry (GME). A brief review of the GME methodology is presented together with a study of the error propagation from measurement uncertainties to the precision of the resulting complex index of refraction N and magneto-optical constant Q. The results are compared with longitudinal GME measurements on bulk polycrystalline cobalt. We observe a strong increase of the resulting relative error as φ0 decreases below 45°. We tested our theoretical estimates by performing GME measurements for polycrystalline cobalt (N=2.20+3.42iN=2.20+3.42i; Q=(2.25−0.80i)×10−2Q=(2.25−0.80i)×10−2)) and found GME measurements to clearly exhibit improved reliability for φ0>30°φ0>30°.