Fabrication of relatively thin diamond films for short mm wave and THz TWT windows

To improve mechanical properties of relatively thin diamond films used in short mm wave and THz TWT windows, we propose a novel fabrication process, in which an ultra-nanocrystalline diamond (UNCD) process is incorporated into the conventional polycrystalline diamond (PCD) deposition. This paper describes the fabrication method, growing process of UNCD on PCD and improvement in fracture strength of the composite diamond films.