Optical Properties and Moisture Stability of HfO2 Thin Films Prepared by Ion Assisted Deposition for UV Applications

Abstract

In this study the progress in the realization of environmentally stable, high phase thickness, long-pass edge filters for UV applications is reported. These filters are characterized by extremely sharp transitions from full transmittance to deep blocking. Such filters are manufactured via physical vapor deposition of Hafnia (HfO2). Filters with highest phase thickness exhibit the steepest edge slopes. In this work we produce two types of filters, the first one manufactured using Ion Assisted Deposition (IAD), and the second one prepared by Physical Vapor Deposition (PVD) technique. When comparing the results for moisture stability of edge filters produced by IAD and PVD, it is found that the filters produced with ion assist exhibit wet-dry shifts in edge wavelength location less than 0.05%.