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

用微波或直流放电等离子体化学气相沉积(CVD)方法生长了金刚石薄膜和颗粒，并在立方氮化硼表面进行了金刚石的外延生长。利用微波CVD可以重复生长金刚石薄膜，生长速度约为3000A/h，除了薄膜和颗粒中的晶格缺陷外，得到的薄膜质量很好。对于高速沉积金刚石来说，直流放电等离子体CVD是非常有用的。对于高质量的薄膜，其生长速度约为20微米/小时。另一方面，在高甲烷浓度(2.3%)和高功率密度的条件下，金刚石的生长速率可达到100-200微米/小时。对于甲烷和氢气的源气系统(气体比…在CH_4/H_2=2/100，总气压：2.6×10~(-4)帕的条件下，测得等离子体正柱中氢原子和电子的统计温度分别为4.8-5×10~(-3)K和1-1.1×10~(-5)K，电离物种的数量很少(-10^&lt；-7&gt；通过计算气体分子在这些温度范围内的平衡常数，发现99%以上的气体分子(H_2和CH_4)被分解成中性的H和C原子。由此可见，碳原子和氢原子的制备对低压下金刚石的生长起着重要的作用。在许多金刚石生长实验中，薄膜都是以多晶状态生长的。目前还不能进行外延生长。这是由于在氢等离子体中衬底表面的稳定性所致。然后，使用立方氮化硼表面作为衬底。结果表明，金刚石薄膜可以平行于衬底表面外延生长。通过控制衬底温度和活性组份的过饱和度，可以得到(100)和(111)晶面的金刚石单晶薄膜，但在金刚石颗粒的生长方面还存在一些问题。较少

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