Accurate determination of optical constants of textured SnO2 using low incidence angle spectroscopic ellipsometry

Accurate optical constants (n and k) of textured SnO2 films were obtained in the range of 0.85–4.6eV using spectroscopic ellipsometry. The angular dependence of the spectroscopic ellipsometer measurement was determined at incident angles 30°, 50°, and 70° from normal to the sample surface. Depolarization components due to texturing and substrate backside reflection were separately analyzed using the measurement on polished and unpolished samples. Depolarization due to substrate backside reflection was modeled accurately. By performing the measurements at a low angle of incidence (30°), where the depolarization due to texturing is at a minimum and therefore can be neglected in the optical model, one can obtain the accurate values of n and k.