Influence Of Purity Of Hfo2 On Reflectance Of Ultraviolet Multilayer

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry (SIMS) equipment respectively. It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films. In addition, the difference of Zr content in the two kinds of HfO2 single layer films was much larger than that of the other impurities such as Ti and Fe, which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2. With these two kinds of HfO2 and the same kind of SiO2, we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm. Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively, which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.