Spectroscopic Ellipsometry (SE)
Spectroscopic ellipsometry is a very strong method widely used for measuring thin film thicknesses. The change in polarization parameters (amplitude and phase change) of light that was bounced-off a sample, is analyzed and fit with a proper model in order to extract information about film thickness, roughness, dielectric function and hence the optical constants such as the real and imaginary part of the complex refractive index. Its model based approach also lets estimation of electrical conductivity, carrier concentration etc. Our group has an SE that operates from deep UV to mid-IR ranges covering an important and relevant spectrum for many exciting applications such as plasmonics, as well as the “quality control” of ALD films. With the option of automatic thickness mapping one can see the variation of the film thicknesses over wafers up to 10 cm.