| Summary: | 碩士 === 國立東華大學 === 材料科學與工程研究所 === 89 === This study is to explore the preparation and structure of nano-diamond and c-BN films grown by MPCVD. The results indicate that increasing the Ar addition in CH4/H2 plasma, or increasing substrate bias voltage, the crystal size of diamond is reduced to nanometer-scale. The growth rate of diamond film is the highest as the Ar addition reaching 50 vol. %. The optimal conditions for c-BN are as the ratio of NH3/B2H6 equals 5, and the substrate is subjected to about 350 V bias by pulsed D.C. In the growth of BN films, the addition of hydrogen, which offer the etching effect, is beneficial to stabilize the structure of c-BN.
The nano-diamond films are used as the substrates to grow c-BN films. The c-BN content rises to 70% due to the well structure and lattice match of diamond and c-BN. The study also shows that the films with higher c-BN content prefer to form on the smooth diamond films grown in CH4/Ar plasma than the rough films grown in CH4/H2 plasma. Moreover, the multilayers composed of nano-diamond and BN films contain upto 90 % c-BN with good adhesion, and the total film thickness reaches about 1 μm.
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