Ellipsometry measures the change in polarisation of light reflected from a surface and derives film thickness and optical constants with sub-nanometre sensitivity. NewRoad supplies the HORIBA UVISEL, Auto SE and Smart SE spectroscopic ellipsometers for both research and production environments.
Polarised light strikes the sample at an oblique angle and the polarisation state of the reflected beam is analysed as the ratio of its p and s components, expressed as the parameters Psi and Delta. Measuring across a spectral range and fitting an optical model of the stack yields the thickness, refractive index and extinction coefficient of every layer.
