PECVD法制备氢化非晶硅薄膜及其性能研究

发布时间：2018-01-28 06:56

本文关键词： 等离子体增强化学气相沉积非晶硅禁带宽度太阳能电池微晶硅　出处：《哈尔滨工业大学》2010年硕士论文　论文类型：学位论文

【摘要】： 硅基薄膜材料作为一种极具潜力的光电能量转化材料,由于其能耗低、可使用廉价衬底,并易大面积沉积等优势而备受人们关注,也使其在太阳能电池领域有很大的竞争力。非晶硅薄膜电池做为其中一个重要的分支,是目前光伏领域的研究热点。本文首先研究了在本设备条件下制备出非晶硅薄膜的均匀性问题,得到影响薄膜沉积均匀性的因素主要是电极间距和射频反射功率的大小。并探讨了样品表面出现斑点及“彩虹条”现象的原因及应对措施。采用等离子体增强化学气相沉积(PECVD)技术,研究了不同射频功率、反应气压和衬底温度对制备非晶硅薄膜的沉积速率和光电特性的影响。结果表明,随衬底温度升高,射频功率增大,反应室内气压升高,沉积速率都增加。但过快的沉积速率使得膜内缺陷增多,性能下降。在可见光波段,薄膜对光的吸收随波长增加而迅速减小,光吸收系数在105cm-1数量级内。所制样品的光学禁带宽度在1.7-2.2eV范围内波动,暗电导率约为10?3S/cm数量级内。利用正交实验,得到了本设备制备出的非晶硅膜的最佳实验参数。其次,采用前文得到的最优参数在不同衬底上制备硅基薄膜。通过结构和性能的测试发现,硅膜在不同衬底表面的结合力都较好,但沉积速率相差很大,以AZO以最高,沉积速率达27.1nm/min,FTO次之,玻璃最低。同时发现,AZO和FTO表面均有膜轻微脱落现象。通过扫描电镜观察到,玻璃基底上为典型的非晶硅膜,而AZO和FTO表面逐渐开始有明显的颗粒团聚现象,但仍是非晶态。同时发现,衬底的结构形态与薄膜沉积和生长有很重要的关系。但对非晶硅沉积来说,最重要的影响因子不是衬底材质(玻璃态,非晶态或晶态),而是沉积工艺参数。最后,本论文初步探索了微晶硅的制备工艺,发现衬底材料的结构与微晶硅薄膜生长有重要关联,表现为衬底材料结晶性愈好,生长的微晶颗粒愈小。
[Abstract]:As a potential photoelectric energy conversion material, silicon-based thin film has attracted much attention due to its advantages of low energy consumption, low cost substrate and easy deposition in large area. As an important branch, amorphous silicon thin film cell is the research hotspot in the field of photovoltaic at present. In this paper, the homogeneity of amorphous silicon thin films prepared under the condition of this equipment is studied. The main factors influencing the uniformity of film deposition are the distance between electrodes and the radio frequency reflection power, and the reasons for the appearance of speckle and "rainbow strip" on the surface of the sample and the countermeasures are discussed. Plasma enhanced chemical vapor deposition (PECVD) technique was used to study different RF power. The effects of reaction pressure and substrate temperature on the deposition rate and photoelectric properties of amorphous silicon thin films were investigated. The results show that the RF power increases with the substrate temperature and the pressure of the reaction chamber increases. The deposition rate increased, but too fast deposition rate increased the defects in the film, the performance of the film decreased. In the visible light band, the absorption of light decreased rapidly with the increase of the wavelength. The optical absorption coefficient is in the order of 105 cm ~ (-1). The optical band gap of the sample fluctuates in the range of 1.7-2.2 EV, and the dark conductivity is about 10? In the order of 3s / cm, the optimum experimental parameters of the amorphous silicon film prepared by this equipment were obtained by orthogonal experiment. Secondly, silicon thin films were prepared on different substrates using the optimal parameters obtained above. The results of structure and performance tests show that the bonding force of silicon films on different substrates is good, but the deposition rate is very different. The AZO was the highest, the deposition rate was 27.1 nm / min, and the glass was the lowest. At the same time, it was found that there was a slight shedding of the film on the surface of AZO and FTO, which was observed by scanning electron microscope. The glass substrate is a typical amorphous silicon film, while the surface of AZO and FTO gradually begins to have obvious particle agglomeration phenomenon, but it is still amorphous. At the same time, it is found. The structure and morphology of the substrates are closely related to the deposition and growth of the films, but the most important factors affecting the deposition of amorphous silicon are not the substrate materials (glass, amorphous or crystalline), but the deposition process parameters. Finally, the preparation process of microcrystalline silicon has been preliminarily explored. It is found that the structure of the substrate is closely related to the growth of microcrystalline silicon thin films. The better the crystallinity of the substrate is, the smaller the microcrystalline particles are.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TN304.055

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