Nanocrystalline diamond growth in a surface-wave plasma

A surface-wave excited plasma is exploited in a diamond growth process by microwave plasma chemical vapor deposition method. Nanocrystalline diamond films with smooth surfaces are obtained from the plasma. As well as characterizing the deposited diamond films, the electron density and the electron temperature of the plasma are determined by using double-probe measurements. The plasma diagnosis reveals low electron temperatures of 2–3 eV in the process region, which is a distinctive characteristic of the surface-wave plasma. The low electron temperature is essential for the continuous re-nucleation of diamond in a hydrogen-rich plasma during the nanocrystalline diamond growth for a wide range of substrate temperature from under 100 to over 700 ∘C.

Research highlights► Nanodiamond grows in surface-wave plasma in a wide range of substrate temperature. ► Surface-wave plasma exhibits low electron temperatures of 2–3 eV. ► Low electron temperature enables continuous re-nucleation of diamond. ► The high rate of re-nucleation permits nanocrystalline diamond to grow.