Deposition Nano-crystalline Diamond Thin Film By Using MPCVD Method

Chemical vapor deposition diamond film is one of the most promisingnew materials due to its advanced physical and chemical property such ashigh hardness, thermal conductivity, electron mobility, microwave chemicalstability and so on. Nano-crystalline film has dual characteristics of diamondand nanometer material, and has more advantages than the ordinarymicrometer diamond film. Microwave chemical vapor deposition (MPCVD)can prepared thin films with high purity, good quality, which make itbecome one of main methods to prepare of nanometer diamond film andattracts extensive attention from many fields. In this study, a novelmultimode resonant cavity MPCVD apparatus which can be used todeposition large scale diamond films with high quality is used to researchthe diamond films deposition.When novel multimode resonant cavity MPCVD apparatus in operation,two microwave modes that TM01and TM02go into the resonant cavity at thesame time, which are above the substrate superimposed. There is muchlarger volume strong electromagnetic field than in the single mode cavity,inspired gas to stimulate a large scale and stable plasma ball. Meanwhilehigh energy density can be obtained, and plasma with high density beformed. The maximum output power of the microwave can reach10KW.The two characters give the insurance of large scale nano-crystallinediamond films with high quality.In the article, the system research from the aspect of that on thesubstrate temperature, microwave power, deposition pressure, carbon sourceconcentration process parameters had been made, on the base of the deposition mechanism of nano-crystalline diamond films, We analyzedvarious process parameters on large scale nano-crystalline diamond filmdeposition mechanism, and mastered the use of the novel multimoderesonant cavity type MPCVD device for the preparation of nano-crystallinediamond film with high quality. The results of the researches show that thereis more second nucleation decreasing in the low substrate temperature, andget the smaller diamond grain; higher microwave power and lower chamberpressure can stimulate larger plasma ball, to prepare uniform surfacenano-crystalline diamond film. The higher the concentration of carbonsource is beneficial to improve the deposition rate and get the smallerdiamond grain.On the basis of various technological parameters on the effect ofnano-crystalline diamond film, the process parameters to depositnano-crystalline diamond film using the experimental device had beenoptimized, the diameter of100mm of large scale diamond films with highquality had been deposited by the optimized process parameters, the surfaceroughness and average grain size of the nano-crystalline diamond films are68.2nm and18.6nm, the speed of the nano-crystalline diamond films is0.3μm/h respectively.The experimental method and deposition process of depositingnano-crystalline diamond films in the novel multimode resonant cavity typeMPCVD device are gotten through the a series of experimental researches,which are the foundation for the deposition of large scale nano-crystallinediamond films with high quality in some degree. Meanwhile, the analysis tothe influence of every parameter to nano-crystalline diamond filmsdeposition can also give theoretical direction to the preparation ofnano-crystalline diamond films with high quality. The research has certain significance on the deposition and application of large scale nano-crystallinediamond films with high quality.