Granular diamond single crystal is an outstanding material. It has many excellent physical and chemical properties, such as extreme hardness, chemical inertness, high thermal conductivity, low electrical conductivity and optical transparency. But further application of granular diamond is limited by its shape. In recent years, diamond film has attracted great attention as a functional material with the development of low-pressure synthesis technology. Compared with the granular diamond, the application prospects of diamond films in the field of electronics technology and acoustics are broader. Now the main technology to prepare diamond films is the low-pressure chemical vapor deposition (CVD) Granular diamond single crystal is an outstanding material. It has many excellent physical and chemical properties, such as extreme hardness, chemical inertness, high thermal conductivity, low electrical conductivity and optical transparency. In further applications of granular diamond is limited by its shape. In Compared with the granular diamond, the application prospects of diamond films in the field of electronics technology and acoustics are broader. Now the main technology To prepare diamond films is the low-pressure chemical vapor deposition (CVD)