Fabrication of Diamond Films at Low Pressure and Low-Temperature by Magneto-Active Microwave Plasma Chemical Vapor Deposition

We succeeded in fabrication of diamond films at substrate temperature of 80° C by using the magneto-active microwave plasma chemical vapor deposition (CVD) method at low pressure (0.1 Torr) with forced substrate cooling. The magneto-active microwave discharge enables us to use high-density microwave plasma under low pressure. High-density plasma-enhanced CVD under low-pressure is advantageous for low-temperature synthesis of diamond films because of decrease in thermal flux to the substrates from neutral gases heated in the plasma. Deposited films were investigated by scanning electron microscopy (SEM), Raman scattering spectroscopy, thin-film X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The fabricated films are randomly oriented polycrystalline diamond of fine crystallite size (below 100 Å). The deposition rate of the diamond films decreased with decreasing substrate temperature in the range below 400° C.