Abstract: Studies of the oxidative degradation of high quality diamond have been conducted to better define the limits of application at high temperature.The infrared(IR)and visible optical performance of polished chemical vapor deposition (CVD) diamond films were degraded seriously after heating at 780℃ for 15min,while heating at 780℃ for 3 min produced a little change .Microscopic etched features were revealed by scanning electron microscopy(SEM),atomic force microscopy (AFM),and Talystep surface profiles.Many of the etched features are concentrated at a variety of defects including grain boundaries,surface porosity etc. The results of heating are increasing the surface roughness of CVD diamond films and degradation of the infrared transmittance.

Key words: Studies of the oxidative degradation of high quality diamond have been conducted to better define the limits of application at high temperature.The infrared(IR)and visible optical performance of polished chemical vapor deposition (CVD) diamond films were degraded seriously after heating at 780℃ for 15min,while heating at 780℃ for 3 min produced a little change .Microscopic etched features were revealed by scanning electron microscopy(SEM),atomic force microscopy (AFM),and Talystep surface profiles.Many of the etched features are concentrated at a variety of defects including grain boundaries,surface porosity etc. The results of heating are increasing the surface roughness of CVD diamond films and degradation of the infrared transmittance.