Developmental Study on Low-tempeature growth technique of crystalline Si by a chemical process of silane with fluorine.

在硅烷和氟气反应化学气相沉积沉积硅薄膜的过程中，这些原料混合产生的反应气流对薄膜的生长起主要作用。在本研究中，我们设计了一个喷嘴为70 mm Phi的立式反应器，其体积为351，并对膜生长进行了研究，以表征这种反应气体流动，并建立如何从膜生长的角度来控制它，从而为反应器的设计提供指导。主要研究了在不同的生长参数如气体流量比、反应压力、气体泵浦速率和气体停留时间等条件下制备a-Si薄膜。从薄膜的均匀性、生长速率、薄膜结构和成分等方面对薄膜进行了评价，为反应流动提供了有价值的信息。结果发现，反应气体的流动特性不同，导致薄膜的生长模式不同，二次反应产生的较高的产物降低了低温结晶，这一问题可以通过控制喷嘴上的气体流量来解决。此外，我们还研究了过渡金属与碳氢化合物在放电流中的反应流动动力学，作为反应流动的模型，并通过识别反应产物和确定它们的速率常数来表征反应流动。

In deposition of Si thin films by reactive CVD with silane and fluorine, the resulting reactive gas flow from mixing these raw materials plays a major role for the growth. In the present study, we designed a vertical type of reactor with a nozzle of 70mm phi, of which volume was 351, and studied the film growth in order to characterize this reactive gas flow and to establish how to control it in terms of film growth, leading to a guide for a design of the reactor. The major efforts were devoted to preparation of a-Si thin film in different growth parameters such as gas a flow ratio, a reaction pressure, a pumping rate for the gas and its residence and so on. The films were evaluated in terms of uniformity, growth rate, film structure and its composition, which gives valuable information of the reactive flow. As a result, we found that there were different characteristics of reactive gas flow leading to different growth modes of films and that a resulting higher products from the secondary reactions degraded the low-temperature crystallization, which was solved by controlling the flux of the gas flow on the nozzle. In addition to this, we investigated a dynamics of reactive flow of transition metals with hydrocarbons in a discharge flow as a model of reactive flow and characterized the reactive flow by identifying the reactive products and determining their rate constants.