TEMPERATURE DISTRIBUTION IN BRIDGMAN EQUIPMENT USED TO OBTAIN CALCIUM FLUORIDE SINGLE CRYSTALS
Pages 211-216
O. Bunoiu, B. Faina, C. Biris, D. Vizman, I. Nicoara
Abstract
Calcium fluoride (CaF2) single crystals have a very important role in optical applications. CaF2 can be used in
a wide region from ultraviolet to infrared. In IR applications it can be used as a prism, as spectroscopic
windows and as lenses. The next generation of optical lithography is being driven by increased demand for
faster and more powerful integrated circuits and calcium fluoride single crystals seems to be a very good
solution for 193 and 157 nm technology. This paper present results concerning the temperature distribution in
a Bridgman set-up used to obtain calcium fluoride single crystals. The numerical modeling of the entire set-up
(global modeling) has been made using CrysVUn software and shows the influence of several parameters
(heater geometry, screens position and geometry) on the temperature field, temperature gradient and on the
solidification interface position.