| Depletion of fossil fuel resources, environmental pollution, climate disasters have become global issues of human development. The development and utilization of clean-renewable energy, which is not only to ensure energy security, but also to help protect human health. Therefore, it becomes a research topic. Solar photovoltaic power generation is considered to be one of the most promising clean energy technologies, and the key is solar cell. Polycrystalline silicon (Poly-Si) thin film solar cells are attracted much attention due to their low material consumption, low cost, high stability, long lifetime and the mature technology of poly-Si thin film microelectronic devices. And preparation of high quality poly-Si thin film is the key issue. Poly-Si thin films are usually fabricated on heterogeneous substrates. During the growth process, deposition conditions have great effect on the structures and properties of films.In this thesis, we prepared poly-Si thin films on graphite and quartz glass substrates by magnetron sputtering (MS) and rapid thermal annealing (RTA) technologies. Effects of substrate temperatures, RTA conditions were investigated systematically. Many kinds of measurements like X-ray Diffraction (XRD), Raman Spectra and Scan Electron Microscopy (SEM) are invited to characterize structure and quality. Our achievements are:1. Poly-Si thin films on graphite and quarts glass substrates were successfully prepared with technologies of MS and RTA. The processes were:Firstly, silicon thin films were fabricated on substrates by MS method, and then RTA method was employed for crystallization of the films. XRD and Raman Spectra indicated that films had better qualities and bigger grain sizes after RTA method. Meanwhile, SEM showed that poly-Si thin films had uniform surfaces and good column-shaped structures.2. As to graphite, substrate temperature of 700℃ was the critical temperature to make films formed with Si (220) preferred orientation. When the temperature was higher than 700℃, silicon thin films on graphite substrates had high Si (220) preferred orientation, and as the temperature raised further, Si (220) preferred orientation was strengthen, grain size was increased, and crystallization degree was enhanced.3. For quartz glass, substrate temperature 800℃ was the critical temperature to make films formed with Si (220) preferred orientation. When the substrate temperature was higher than 800℃ and further heated, Si (220) preferred orientation was markedly strengthened and degree of crystallization was enhanced significantly as well.4. Annealing treatment had great influence on the formation of polycrystalline phase. Using RTA method, crystallization of film was significantly increased, and grain size became larger, and without RTA method, samples were mainly amorphous phase and had small grain sizes. |
