基于中压等离子体技术的多晶硅薄膜快速晶化及低温生长

发布时间：2018-08-02 12:55

【摘要】：多晶硅薄膜因其独特的光学、电学性能及成本优势被认为是信息产业和太阳能光伏发电产业的关键材料。低温、快速制备高质量多晶硅薄膜是其重要的发展方向。在众多低温工艺中,H原子被广泛认为对多晶硅薄膜制备有着重要的促进作用。近些年来新开发的中压等离子体技术其中一个重要的特性就是拥有高的H原子密度,因此其可能在低温制备多晶硅薄膜方面有着极大的潜力。本论文以中压等离子体技术为基础,开发一种新的非晶硅薄膜快速退火晶化的方法,验证高密度H原子在晶化过程中起到的重要作用;再根据其高密度H原子及高温条件下独特的团簇式高速外延的特点,探究低温条件下基于玻璃衬底的多晶硅沉积工艺。(1)利用Ar、H2作为等离子体气体而产生的中压等离子体对1μm厚的无氢非晶硅薄膜进行退火,几秒钟内即可获得高结晶度的微晶硅薄膜,衬底温度低于600℃。中压等离子体提供的热能及高密度H原子化学退火作用是其能够实现低温快速退火重要原因。实验也探究了H2浓度、等离子体能量和退火时间对薄膜的形态与结晶度的影响,发现合理的提高功率和H原子浓度是短时间退火得到高结晶度薄膜的关键控制工艺,进一步提高H原子活性及延长退火时间会造成薄膜表面的刻蚀。另外也对中压等离子体退火机制做出了描述。(2)利用中压等离子体CVD技术在玻璃衬底上实现了低温多晶硅薄膜的制备。在110℃的衬底整体温度条件下获得了平整、连续的多晶硅薄膜,沉积速率达到了7.4μm/min,高于传统CVD方法不止一个数量级。实验同时探究了沉积工艺对薄膜质量和沉积速率的影响:提高射频功率可以提高薄膜质量和沉积速率;提高硅烷浓度可提高沉积速率,但薄膜质量先提升再降低。通过提高等离子体活性的方式可进一步降低整体衬底温度至85℃,并获得完全结晶、形貌平整的多晶硅薄膜。通过以上述两方面的研究,表明了中压等离子体在低温高速制备多晶硅薄膜的优越性。
[Abstract]:Polysilicon thin film is considered to be the key material in the information industry and the solar photovoltaic power generation industry because of its unique optics, electrical properties and cost advantages. Low temperature and rapid preparation of high quality polysilicon thin film are its important development direction. In many low temperature processes, H atoms are widely recognized as an important promotion to the preparation of polysilicon thin films. In recent years, one of the most important characteristics of the newly developed medium pressure plasma technology is to have a high H atomic density. Therefore, it may have great potential in the preparation of polysilicon thin films at low temperature. This paper is based on the medium pressure plasma technology, and develops a new method of rapid annealing of amorphous silicon thin films. The important role of high density H atoms in crystallization process is proved, and according to the characteristics of high density H atom and high speed epitaxy under high temperature conditions, the polycrystalline silicon deposition process based on glass substrate at low temperature is explored. (1) the medium pressure plasma produced by Ar, H2 as the plasma body of the plasma to the non hydrogen non hydrogen non. The crystalline silicon thin film can be annealed in a few seconds. The substrate temperature is lower than 600. The thermal energy provided by the medium pressure plasma and the high density H atomic chemical annealing are important reasons for the rapid annealing at low temperature. The experiment also explores the H2 concentration, the plasma energy and the annealing time on the shape of the film. With the influence of state and crystallinity, it is found that reasonable increase of power and H atom concentration is the key control technology for short time annealing of high crystallinity thin films. Further improving the H atomic activity and prolonging the annealing time will cause the etching of the film surface. In addition, the medium pressure plasma annealing machine is also described. (2) the use of medium pressure plasma CV D technology has realized the preparation of low temperature polysilicon thin film on the glass substrate. The smooth, continuous polysilicon film was obtained at the overall temperature of 110 centigrade. The deposition rate reached 7.4 mu, higher than the traditional CVD method more than one order of magnitude. The effect of the deposition process on the film quality and deposition rate was also investigated. Radio frequency power can improve the film quality and deposition rate, and increase the silane concentration to increase the deposition rate, but the film quality first increases and then decreases. By increasing the plasma activity, the overall substrate temperature can be further reduced to 85 degrees C, and the complete crystalline and smooth polycrystalline silicon film is obtained. Through the above two aspects of research, The superiority of medium pressure plasma in preparing polycrystalline silicon thin films at low temperature and high speed is demonstrated.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN304.12;TB383.2

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