Deposition Of Nanocrystalline Diamond Thick Film On Mo By HFCVD

Chemical vapor deposited?CVD?diamond has wide application prospects in many high-tech fields because of its extremely high hardness,exceptional chemical inertness,high thermal conductivity and other excellent performance.Nanocrystalline diamond?NCD?has better toughness and coefficient of friction than CVD diamond is one of the hot research materials.This paper reports the nucleation and growth of nanocrystalline diamond on Mo by HFCVD system.The influence of methane concentration and deposition temperature in the nucleation stage had been investigated.The morphology and structure of diamond films were examined by Raman spectroscopy?Raman?,field-emission scanning electron microscope?SEM?and Atomic Force Microscope?AFM?.The main research work includes:1.The influence of methane flow on nucleation of NCD was researched.The results indicate that the nucleation of diamond decrease after a little increment with the methane flow increasing.The nucleation and grain size perform well which prefer to the deposition of NCD.2.The influence of substrate temperature on nucleation of NCD was researched.The results indicate that the grain size of diamond will be larger with the temperature increase.The grain size kept 300nm when the temperature got 800?,which would turn to micrometer size with the temperature increasing.This is not suitable to deposit NCD.3.The influence of nitrogen injection on nucleation of NCD was researched.The results show that the nucleation and growth rate will increase much with little concentrate of nitrogen.The main effect was to accelerate the growth of crystal and form the?100?and?111?when the concentrate of nitrogen below 10%.The nucleation rate also increased from2×10⁸cm^-2 to 3×10¹⁰cm^-2.The crystal became cauliflower-like when the concentration of nitrogen at 10²0%.4.We deposited three kinds of NCD films with different nitrogen concentration.The result shows that the NCD film's adhesion on the substrate is obviously better with no nitrogen injection.However,its friction coefficient is found to be largest.The friction coefficient will decrease from 0.266 to 0.063 with 20%nitrogen injection.But the film is not satisfied for applying with the adhesion also be decreased.The NCD film with 10%nitrogen injection has perfect friction coefficient and adhesion ability which more available.