Chemically vapor deposited silicon carbide (SiC) for optical applications

Abstract

In this paper we present important physical, thermal, mechanical, and optical properties of cubic (β) silicon carbide produced via a bulk chemical vapor deposition (CVD) process developed at CVD Incorporated. This CVD SiC has been identified as the leading mirror material for high energy synchrotron radiation because of its high thermal conductivity, low thermal expansion, high polishability, and high reflectance in the vacuum UV. However, it has been difficult to obtain high quality, monolithic, CVD SiC mirrors in large sizes, i.e., greater than 10–20 cm. Recently, CVD Incorporated has been successful in scaling an SiC CVD process to produce large monolithic pieces of SiC up to 60 cm (24 in.) in diameter and plates up to 76 cm (30 in.) long by 46 cm (18 in.) wide with thicknesses up to 13 mm (0.5 in.). The properties of this material that make it attractive for optical applications, such as synchrotron optics, will be discussed.