マイクロ波プラズマCVDによるNi多結晶と単結晶へのダイヤモンド合成

抄録

Because diamond films are synthesized from vapor phase CVD, studies are being conducted on applications of their properties as industrial materials. Epitaxial growth is necessary, however to obtain properties like those of natural diamond, and reports exist of epitaxial growth on diamond or cBN substrates, and of local epitaxial growth on Ni substrates.
To obtain basic data for diamond epitaxial growth, diamond synthesis was carried out by microwave plasma CVD from a methane-hydrogen reaction gas system on substrates of poly and single-crystal Ni, having nearly the same lattice distance as diamond.
On poly-crystal Ni substrates, it was found that although the range of conditions suitable for diamond growth were narrow, high-quality diamond having a diamond peak of narrow FWHM on the Raman spectrum could be obtained if suitable conditions were chosen.
On single-crystal Ni substrates, on the other hand, hetero epitaxial growth was not observed, and the quality of the diamonds grown was degraded be the presence of DLC.
This phenomenon is attributed to the crystalline stability of Ni substrates in the diamond synthesis atomosphere, and the instability of the crystalline orientation of Ni substrates during fluctuations in substrate temperature.