Low Temperature Synthesis of Diamond Films with Electron Cyclotron Resonance Plasma Chemical Vapor Deposition

In this paper we review our previous work and present additional results on polycrystalline diamond film synthesis in a CH 4 /H 2 /O 2 microwave discharge at substrate temperatures down to 300°C. Low temperature diamond growth was achieved by combining three strategies : the low temperature limit for diamond growth was reduced by decreasing the total gas pressure in the deposition chamber to 1-3 Torr ; low pressure diamond growth was enhanced by applying a static axial magnetic field to the plasma generation region to increase gas dissociation and ionization in the Torr pressure range ; and the microwave input power was pulse modulated to control the relative fluxes of neutral atomic hydrogen and charged positive ions to the substrate. With these combined methods, high quality diamond films exhibiting a clearly defined Raman phonon peak could be grown at backside substrate temperatures from 300°C to 500°C.