Effect of Deposition Angle on the Optical and the Structural Properties of Ta2O5 Thin Films Fabricated by Using Glancing Angle Deposition

In this paper, the effect of deposition angle on the optical and the structural properties of Ta2O5 thin films fabricated by using electron beam evaporation with a glancing angle deposition (GLAD) technique is reported. The refractive index and the porosity at various deposition angles are studied. We see that the refractive index decreases and the porosity increases with increasing deposition angle. The calculated in-plane birefringence of GLAD Ta2O5 films shows a maximum value of 0.04 at a deposition angle of 70. The microstructure and the morphology are also investigated by using scanning electron microscope (SEM). The cross-sectional SEM images illustrate a highly oriented microstructure composed of slanted columns and voids due to the shadowing effect and limited adatom diffusion. Therefore, the glancing angle deposition technique is an original way to control the columnar microstructure with an enhanced birefringence. KCI Citation Count: 7