High growth rate deposition of diamond particles and thin films in arc and/or glow discharge region.

利用微波或直流放电等离子体化学气相沉积（CVD）技术制备了金刚石薄膜和金刚石颗粒，并在立方氮化硼表面进行了金刚石外延生长。利用微波CVD技术，金刚石薄膜的生长速度可达3000A/h左右，除薄膜和颗粒中存在晶格缺陷外，所得到的薄膜质量都很好。对于高速率的金刚石沉积，直流放电等离子体CVD是非常有用的。高质量薄膜的生长速度约为20mum/h。另一方面，如果在高甲烷浓度（2.3%）和高功率密度下操作，则生长速度可提高到100-200mum/h左右。采用Langmuir单探针法和发射光谱法测量了直流放电等离子体CVD生长金刚石过程中的等离子体特性。对于甲烷和氢气的气源系统（气体比为…More: CH_4/H_2=2/100，总气压为2.6 10^4 Pa），得到等离子体正极柱中氢原子和电子的统计温度分别为4.8-5 × 10^3K和1-1.1 × 10^5K，电离物质的数量相当小（-10^<-7>）。通过计算这些温度区域内气体分子的平衡常数，发现99%以上的分子（H_2和CH_4）分解为中性的H和C原子。由此可见，碳原子和氢原子的制备对金刚石的低压生长起着重要的作用。在许多金刚石生长实验中，金刚石薄膜以多晶态生长。目前还不能进行外延生长。造成这种现象的原因是由于氢等离子体中衬底表面的稳定性。然后，用立方氮化硼表面作为衬底。结果表明，金刚石薄膜可以沿与衬底表面平行的方向外延生长。通过对衬底温度和活性物质过饱和度的精细控制，可以得到具有（100）和（111）平面的金刚石单晶薄膜。工业用金刚石颗粒的生长还存在一些问题。少

Diamond thin films and particles have been grown by micro-wave or DC discharge plasma chemical vapor deposition(CVD) and the epitaxial growth of diamond has also been performed on cubic born-nitride surfaces.By using micro-wave CVD, diamond thin films can be grown reproducibly with the growth rate of about 3000A/h and it is found that the quality of the films obtained is excellent except the lattice defects included in the films and particles.For high rate deposition of diamond, it is revealed that DC discharge plasma CVD is quite useful. The growth rate of the films is about 20mum/h for the high quality one. On the other hand, if this method is operated under high methane concentration(2 3%)and high electric power density, the growth rate increases to about 100-200mum/h.The characteristics of the plasma during diamond growth by DC discharge plasma CVD are measured by the Langmuir single probe method and emission spectrometry. For the source gas system of methane and hydrogen(gas ratio … More : CH_4/H_2=2/100, total gas pressure:2.6 10^4 Pa), it is found that the statistical temperatures of hydrogen atoms and electrons in the positive column of the plasma are obtained to be 4.8-5x10^3K and 1-1.1x10^5K respectively, and the amount of ionized species is fairly small(-10^<-7>).By calculating the equilibrium constant of gas molecules in these temperature regions, it is found that the molecules over 99% (H_2 and CH_4) are decomposed to the neutral H and C atoms.From these results, the preparation of atomic carbon and hydrogen plays important role for the growth of diamond at a low pressure.In many experiments of diamond growth, the films grow in polycrystalline state. The epitaxial growth can not be performed yet. The reason of this fact is due to the stability of the substrate surfaces in hydrogen plasma.Then, the cubic boron-nitride surfaces are used as a substrate. It is found that the diamond thin films can be grown epitaxially with the parallel orientation to the substrate surfaces. The single crystal films of diamond with (100) and (111) planes can be obtained with the detailed control of substrate temperature and supersaturation of active species.There remained some problems for the growth of diamond particles useful for industrial fields. Less