A method for preparing silicon thin film by hot wire chemical vapor deposition using tantalum carbide coated tantalum wire as catalyst. When the hot wire catalyst was used to prepare silicon thin film, the tantalum carbide layer on the surface of the catalyst was well maintained, and no silicide formation was observed. In other words, the hot wire catalyst showed good anti-aging performance and had the potential to significantly extend the service life of the hot wire catalyst. The preparation method of the catalyst is simple and the conditions are easy to control. It is suitable for the preparation of intrinsic, doped and compound silicon films with various crystallization degrees by hot wire chemical vapor deposition.
As the substrate material of silicon thin film photovoltaic cell of the second generation solar cell, more and more people pay attention to silicon thin film. Hot wire chemical vapor deposition, also known as catalytic chemical vapor deposition (CVD), is a new film preparation technology developed in 1970s. In the process of silicon thin film prepared by hot wire chemical vapor deposition, the gaseous precursor material underwent multi-phase catalytic cracking reaction through high temperature hot wire catalyst, and the activated intermediate species were deposited on the substrate and further grew to form silicon thin film. Compared with the current mature technology of preparing silicon film by plasma chemical vapor deposition, hot wire chemical vapor deposition has the advantages of simple equipment, low cost, fast film deposition speed, deposition process does not involve a large number of charged species, and high quality of prepared film. Therefore, hot wire chemical vapor deposition has become a new technology which can prepare intrinsic, doping and many kinds of silicon films with various crystallization degrees, and has a good prospect of industrial application.
However, the development of hot wire chemical vapor deposition silicon thin film has encountered some problems, among which the aging of hot wire catalyst is one of the bottlenecks restricting its industrial application. Using conventional hot wire tungsten filament or tantalum catalysts were hot filament chemical vapor deposition of preparation of silicon thin film, usually within a few minutes the surface of the metal wire will generate a tungsten silicide layer or tantalum silicide, as the reaction progresses, silicon species in diffusion, further solid phase reaction occurs, the silicide layer thickness is increasing, As a result, the surface structure and overall performance of the hot wire catalyst change significantly, the mechanical strength deteriorates, and it is easy to fracture. The service life of the hot wire catalyst is shortened, and the deposition of silicon film is seriously affected. Therefore, it is urgent to solve the aging problem of hot wire catalysts during the preparation of silicon thin films by hot wire chemical vapor deposition.
