The Study Of MPCVD Diamond Film Preparation And Application

Diamond is an ideal material for many applications because of its perfect properties in mechanical, optical,thermal and electrical. However,natural diamond is rare and expensive, which limits its extensive usage. During science and technology growth in the last decades, there is a great development to synthetic diamond research .High Pressure High Temperature method (HPHT) and low-pressure Chemical Vapor Deposition(CVD) method are the two main methods in fabricating diamond.Microwave PCVD method is one of the most suitable method in fabricating high quality CVD diamond films.Because of its low contaminated and stable plasma discharge,microwave PCVD method is considered as the best method for fabricating high quality transparent diamond films.There are many studies in microwave PCVD diamond films during the past years,so in this thesis,the diamond films are fabricated by self-designed direct coupling quartz tube microwave plasma chemical vapor deposition system and the diamond films's colourometry are studied.Then, the plasma characteristics in the sample fabricating was studied by utilizing high resolution Optical Multi-channel Analyzer (OMA). Results are as follows .Diamond films depositied on silicon or quartz glass. Raman spectrometer, SEM, thickness meter were used to analyzed the quality of diamond film. It was shown that diamond films have complete crystal at 2.5Kpa, 450℃.The flow of Ar, CH4 and H2 is respectively standard-state 40 , 4 and 60 cubic centimeter per minute.And the microwave power is 500 to 700W. The influence of hydrogen concentration on the chromaticity of MPCVD diamond films was studied. It was shown that the saturated purity and color purity of diamond films increased with H2 concent ration;they reached their highest values of 8. 5 % and 9. 5 % , respectively , when CH4 concentration increased to 5.863% , and then began to reduce with further increasing the hydrogen concentration. And Ar spectral characteristic was studied. It was shown that excitation temperature increased with microwave power, excitation temperature was decreased with the gas flow quantity and spectral line intensity increased with microwave power, it was decreased at 550W and 700W,and then it increase. These points are the key points in MPCVD diamond films.So, the regularity and experimental parameters of fabricated diamond were summarized.Then, the applications of diamond film in the field of mechanical processing have studied.Diamond film deposited on the alloy drills. It was shown that the using life of drill was improved 15 to 21 hours.