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Diamond Growth by Atomic Vapor Deposition and CVD in low pressure ambient

在低压环境下通过原子气相沉积和 CVD 生长金刚石

基本信息

批准号：
02805005
负责人：
INUZUKA Tadao
金额：
$ 1.15万
依托单位：
Aoyama Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02805005/
关键词：
Diamond CVD method Atomic vapor deposition Carbon cluster Low temperature process

项目摘要

Two kinds of experiments have been performed to reveal the fundamental process of diamond formation from the vapor phase and also to know the physical meaning of growing temperature such as 800-900C.For the first experiment, carbon atoms prepared by removing carbon clusters are used as the source gas for diamond deposition in a hydrogen ambient of 10 Torr. In this system, diamond particles are found by high resolution TEM. If carbon vapor containing carbon clusters is used as the source gas, amorphous carbon films grow even at the elevated substrate temperature of about 850C.For the second experiment, the hot-filament CVD method is used with the mixture gas of methane and hydrogen at the lower gas pressure of 0.01-1 Torr. The growth rate of diamond is remarkably reduced as the ambient gas pressure is lowered to about 0.01Torr. Below this pressure, diamond growth cannot be found by TEM observation.Assuming the gas temperature of 2000C around the hotfilament, the concentration of active species such as hydrog en molecules, H, C, CH etc. is calculated. The mean free path of H and C at the gas temperature of about 2000C is also calculated. From these results, it is found that atomic carbon and atomic hydrogen arrive to the substrate surface without collision to the other species.Considering these two experiments, it is shown that diamond can be grown preparing atomic carbon and hydrogen. The heating of growing surfaces is not required for the crystallization of diamond but for the dissociation of hydrogen from the surface. The remained important task is to perform the CVD process using the reaction of hydrogen extraction by atomic hydrogen. This will realize the low temperature process of diamond formation from the vapor phase.

为了揭示气相金刚石形成的基本过程，并了解生长温度（例如 800-900C）的物理意义，我们进行了两种实验。第一个实验是在 10 Torr 的氢气环境中，使用去除碳簇制备的碳原子作为金刚石沉积的源气体。在该系统中，通过高分辨率 TEM 发现金刚石颗粒。如果使用含有碳簇的碳蒸气作为源气体，即使在约850℃的升高的衬底温度下，非晶碳膜也会生长。对于第二个实验，在0.01-1Torr的较低气压下使用热丝CVD方法，使用甲烷和氢气的混合气体。当环境气压降低至约0.01Torr时，金刚石的生长速率显着降低。低于此压力，TEM观察无法发现金刚石生长。假设热丝周围的气体温度为2000C，计算氢分子、H、C、CH等活性物质的浓度。还计算了气体温度约为2000℃时H和C的平均自由程。从这些结果中，发现原子碳和原子氢到达基底表面而没有与其他物质碰撞。考虑这两个实验，表明可以制备金刚石来制备原子碳和氢。金刚石结晶不需要加热生长表面，而是氢从表面解离。剩下的重要任务是利用原子氢提取氢的反应来执行CVD工艺。这将实现气相形成金刚石的低温过程。