Study Of Processing And Properties Of AIN Films Prepared By Magnetron Reactive Sputtering

Diamond has excellent properties such as good transmission in the infrared, low absorption coefficient, high resistance to thermal shock and friction. Diamond is an ideal material for airborne windows and domes for high-speed flight. However, diamond is subject to oxidation in air at temperatures greater than 750℃, and the optical transmission is degraded sharp. In order to meet the need for applications of high-speed or high-temperature, the anti-oxidation and anti-reflective films must be prepared on the diamond surface. Aluminum nitride (A1N) are promising anti-oxidation films with good physical, chemical properties and good adhesion to diamond. Great progress has been made in the researches about A1N anti-oxidation films overseas. But no domestic work has been done on A1N optical and protective films. Researches of the paper mostly concentrate on preparation of A1N films and the functions of experiment parameters on films structure and properties. The main contents and results are listed as follows:With the help of OPFCAD software, anti-reflective films containing A1N on the diamond substrate are designed and analysis of structure sensitive factor and variation are done. After A1N films deposited on the surfaces of diamond, the average transmittance in 8 - 11.4μm waveband can exceed 85%, which can meet the requirements of missile dome in infrared application.A1N films are prepared on silicon substrates by radio frequency magnetron reactive sputtering in order to get the functions of the main experiment parameters such as RF power, gas flow, vacuum gas pressure, target-substrate distance and substrate temperature on deposition rate of films. The optimized parameters ranges are obtained by considering films deposition rate, composition and structure. The orthogonal experiment results prove that the effect of RF power on deposition rate is most significant. The experiment parameters of the biggest deposition rate are decided.On the basis of experiment results, the nitride reaction on target surface as well as the dependence of deposition rate on N2 flow rate is analyzed theoretically.XPS analysis as well as XRD and Vickers hardness is made. XPS results confirm the formation of A1N, and the formation of thin layer of amorphous aluminum oxide or aluminum oxynitrides on films surface is deduced. XRD results show thatdeposited A1N films are hexagonal, and films are amorphous under 380℃ when depositing, films come into crystallizing as the substrate temperature increases.