Studies on surface reaction process and thin film formation by controlling radicals

在本项目中，我们首先系统地研究了硅烷/氢混合气体在ECR等离子体中沉积薄膜的结晶度与气相信息的相关性。结果表明，离子通量的降低有助于结晶度的提高。在此基础上，我们开发了一种新的方法来沉积无离子的薄膜，即只有中性的永磁体。利用这种方法，我们成功地合成了高结晶度、表面光滑的多晶薄膜。然而，沉积速率降低到传统方法的十分之一。为了解决这个问题，我们尝试了一种新的两步生长方法。在该方法中，离子在生长初期通过永磁体去除。该步骤完成后，将永磁体从等离子体中去除，使用传统的ECR硅烷/氢等离子体沉积薄膜。更确切地说，包括离子和中性物质。因此，我们成功地合成了结晶度高、表面光滑、沉积速率相对较高的薄膜。此外，我们还发现离子种类对结晶相成核的干扰尤为明显。在金刚石的形成过程中，我们利用真空紫外吸收光谱和光学发射光谱从自由基行为与薄膜质量的关系出发，阐明了自由基的作用。因此，碳原子促进了非金刚石相的形成，OH自由基促进了氢原子终止金刚石表面的抽离反应。在1996年至1998年的这个项目中，我们成功地通过阐明多晶硅和金刚石薄膜形成过程中的作用获得了重要的发现。此外，在此基础上，我们成功地开发了通过控制自由基来获得更高质量薄膜的方法。少

In this project, firstly we investigated systematically the correlation between the crystallinity of the deposited films and the information of gas phase in ECR plasma using silane / hydrogen mixture gases. As a result, we found that the reduction of ion flux contributed to the improvement of the crystallinity. On the basis of this result, we developed a novel method for depositing films without ionic species, namely, only neutral species using permanent magnets. Using this method, we have successfully synthesized the polycrystalline films with high crystallinty and smooth surfase. However, the deposition rate was reduced to be a tenth of that using the conventional method. To solve this problem, we have tried a novel two step growth method. In the method, ionic species were removed at the initial growth stage by using permanent magnets. After this step, the permanent magnets were removed from the plasma, the films were deposited by using the conventional ECR silane/hydrogen plasma., n … More amely including ionic and neutral species. As a result, we have successfully synthesized the films with high crystallinity, smooth surface and relatively high deposition rate. Moreover, we have found that ionic species disturb the nucleation of the crystalline phase especially.In a diamond formation process, we have clarified the role of radicals from the correlation between the film quality and the behaviors of the radicals using vacuum ultraviolet absorption spectroscopy and optical emission spectroscopy. As a result, carbon atom contributes to the formation of non-diamond phase while OH radical promotes the abstraction reaction of hydrogen atom terminating the diamond surface.In this project from 1996 to 1998, we have successfully obtained important findings by elucidating the roles in the polycrystalline silicon and diamond film formation processes. Moreover, on the basis of the findings, we have successfully developed the methods promising to obtain the films with further better quality by controlling the radicals. Less