Design and Process Development of Poly-crystalline Silicon Thin Film Solar Cells

• Main Authors: Chi-wei Kao, 高啟瑋
• Other Authors: Jian-yang Lin
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/05676266390989885057

碩士 === 國立雲林科技大學 === 電子與資訊工程研究所 === 93 === This work has studied on the poly-crystalline silicon thin film solar cell process development. Baseline process flow of the thin film solar cell has been designated to achieve high conversion efficiency. Basically, Via hole Etching for the Separation of Thin film (VEST) structure is used for the solar cells which not only is of modular process but also can reduce the manufacturing cost. This work utilized LPCVD to deposit poly-crystalline silicon thin film on a single-crystalline silicon wafer with a thin SiO2 film on it. Thermal evaporation was used to deposit Al thin film on the poly-crystalline silicon thin film and then annealed with a phosphorous doping disk for the gettering. The phosphorous atoms can getter the impurities from the p-type silicon substrate to have a purer substrate. RIE was then used to etch Via-hole structure in the poly-Si film. Besides, antireflection coating of SiO2 layer has been used to reduce the light reflection on the cell surface and to increase the light absorption. This work used thermal annealing to replace the ZMR, which has proved that the grain size and the surface roughness became larger and the surface became smoother with increased anneal temperature and anneal time. This work used boron or phosphorous doping disk for the solid-source thermal diffusion and doped impurities in the solar cell. The solar spectrum on earth’s surface has larger intensity for the shorter wavelengths. In order to collect the photo-carriers generated by the short-wavelength light and to reduce the carrier recombination, a shallow junction is required for the solar cells. Simulation by PC1D in this work, efficiency can be achieved as high as 8.2% for the VEST solar cells. VEST cells with further passivation process can achieve a efficiency of 10%.