The Quality Effect Of Diamond Film By Microwave Plasma CVD Process Parameters

Chemical vapor deposition（CVD） diamond film has best hardness, lowcoefficient of thermal expansion, excellent chemical stability, highwear-resistance, high thermal conductivity, wide band gap, as well as goodoptical transmittance from the far infrared to the ultraviolet and excellentperformance in many fields of advanced technology, which has a very goodapplications. Compared with other CVD methods, microwave plasmachemical vapor deposition （MPCVD） diamond film has non-electrodepollution, high crystalline, few defects, surface roughness and otheradvantages. MPCVD is the most ideal method of preparation for high qualitydiamond films.This paper is in a new multimode MPCVD device for growth large areahigh quality diamond film preparation research. The device uses a microwavein multimode cavity with TM₀₁mode and TM₀₂ mode, two kinds of modecomplementary principle, enhancing the plasma discharge region, in whichcan have a diameter of150mm plasma ball, for large area high qualitydiamond films obtained with experimental conditions. First, on large areadiamond films growth process parameters were studied, based on thepreparation of high quality of large area diamond films. Then through theoptimization of experimental parameters, the （100） crystal plane of large areadiamond films was made by MPCVD.In the preparation process of diamond film, microwave power, gaspressure, methane concentration, substrate temperature and other processparameters influence the final preparation of diamond films quality. Therefore,for different MPCVD devices, the process parameters need to be studied. This paper is based on lots of documents, on the device of diamond film on thegrowth parameters of careful study. The results show that, when the methaneconcentration in0.5%¹.5%, the substrate temperature at800to880℃,prepared sp³high carbon content, good crystallization degree, completecrystal shape, and fewer defects of high quality diamond films. In the newnovel MPCVD device, large area diamond films was successfully preparedwith the diameter100mm. Scanning electron microscopy （SEM） images showthat the surface morphology of diamond films, crystal particles distribution isuniform; Raman spectroscopic detection shows that diamond film of SP3carbon content is quit well; X ray diffraction （XRD） indicated that diamondfilm has crystalline integrity, good crystallization degree.Height （100） preferred orientation of the diamond film has the bestoptical properties and thermal conductivity, which is suitable for opticalwindow, high power microwave window, and heat sink material etc.In this paper, based on the preparation of large area diamond films,discussed （100） preferred orientation growth of diamond films in the MPCVDdevice. In the preferred orientation of diamond film growth process, thenucleation, substrate temperature and concentration of methane and otherprocess parameters are demand. Through these parameters were studied, inorder to grasp the related laws. The results show that, the microwave powerwas4.5kW, the pressure is3.6kPa, methane flow2.4sccm, hydrogen flowrate300sccm, the surface of the substrate temperature is810℃, after hydrogenplasma cooling process, can produce smooth surface, internal defects less is（100） crystal plane orientation of large area high quality diamond membrane.SEM picture show （100） crystal plane crystal clear, average particles smallerthan5μm; Raman spectroscopic characterization of thin film diamond phasecontent is high, and fewer impurities; from SEM section shows the growth rate was1umh^-1.Through researching process parameters of large area diamond films inthe new novel MPCVD device and （100） crystal plane diamond film growth,preparation of large area high quality diamond films can be for used, in theoptical window, heat sink materials, supplying experimental basis.