氢对PECVD法制备硅基薄膜沉积速率、膜结构及性能的影响

发布时间：2018-03-11 05:07

本文选题：PECVD　切入点：硅基薄膜　出处：《汕头大学》2010年硕士论文　论文类型：学位论文

【摘要】：硅基薄膜作为一类重要的光电功能材料,由于其独特的性能,使其在新能源、信息显示、光敏器件等高科技领域具有十分重要的应用价值。当前,氢化非晶硅(a-Si:H)薄膜已经广泛应用于太阳能电池、液晶显示等领域。但是由于其含有大量的缺陷态(主要是悬挂键),使其在实际应用方面受到一定限制,其中最主要的问题是光致衰退效应。各国研究人员经过大量研究,逐渐认识到氢对硅基薄膜的结构和性能有非常重要的影响作用。一方面,氢以单氢化合物(Si-H)的方式与硅基薄膜相结合,起饱和薄膜中悬挂键的作用。这使得氢化非晶硅的缺陷态密度比未氢化的非晶硅大大降低,从而使其符合器件级材料的要求。另一方面,氢也以多氢化合物(Si-H2、Si-H3和(Si-H2)n)的方式与硅基薄膜相结合,从而引入新的缺陷,使带隙中的局域态密度增大。在硅基薄膜的制备过程中,氢对薄膜的晶化有至关重要的作用,而薄膜的晶化又影响其光电性能,因此研究氢对硅基薄膜的作用具有十分重要的意义。本文对采用PECVD系统制备的硅基薄膜进行了光电性能的研究。本论文的研究内容主要由四大部分组成。第一,通过选择不同衬底,设计不同工艺条件,制备不同结构和性能的硅基薄膜；第二,通过傅立叶变换红外透射谱对硅基薄膜的氢含量及其键合模式进行分析；第三,通过紫外-可见光光透射谱研究硅基薄膜的光学性能；第四,通过静电计分析研究硅基薄膜的电学性能。本论文中,我们着重研究了氢稀释率对硅基薄膜生长速率、氢含量及基键合模式影响,氢含量及其键合模式对薄膜光电性能结构的影响。本论文也简单探讨了钠、镁、钙杂质对硅基薄膜电学性能的影响。实验结果表明,在一定范围内,随着氢稀释率的提高,硅基薄膜的生长速率降低,氢含量增加,室温暗电导率减小,电导激活能增大,光敏性变好。硅基薄膜中Si-H形式的氢含量增大时,薄膜光学带隙减小。硅基薄膜中的氢,尤其是Si-H形式的氢有助于提高硅基薄膜的光电性能。硅基薄膜由于钠、镁、钙杂质的进入会导致其光敏性降低,暗电导率变大、电导激活能变小。
[Abstract]:As a kind of important optoelectronic functional material, silicon-based thin film has a very important application value in new energy, information display, Guang Min devices and other high-tech fields because of its unique properties. Hydrogenated amorphous silicon (a-Si: h) thin films have been widely used in solar cells, liquid crystal display and other fields. The most important problem is the photo-induced decay. After a lot of research, researchers in various countries have come to realize that hydrogen plays a very important role in the structure and properties of silicon-based films. Hydrogen acts as a hanging bond in the saturated film by combining with the silicon film in the form of a monohydrogen compound, which greatly reduces the density of the defect states of the hydrogenated amorphous silicon than that of the unhydrogenated amorphous silicon. On the other hand, hydrogen is also combined with silicon based thin films in the form of polyhydrogen compounds such as Si-H2OSi-H3 and Si-H2Ns, thus introducing new defects and increasing the local density of states in the band gap. Hydrogen plays an important role in the crystallization of thin films, and the crystallization of films affects their photoelectric properties. Therefore, it is of great significance to study the effect of hydrogen on silicon based films. In this paper, the optoelectronic properties of silicon based thin films prepared by PECVD system are studied. The research contents of this thesis are mainly composed of four parts. Firstly, by selecting different substrates, different process conditions are designed. Silicon based films with different structures and properties were prepared. Secondly, the hydrogen content and bonding mode of silicon based films were analyzed by Fourier transform infrared transmission spectroscopy. Thirdly, the optical properties of silicon based films were studied by UV-Vis optical transmission spectroscopy. In this paper, we focus on the effects of hydrogen dilution on the growth rate, hydrogen content and bonding mode of silicon based films. The effects of sodium, magnesium and calcium impurities on the electrical properties of silicon based films are also discussed in this paper. The experimental results show that in a certain range, with the increase of hydrogen dilution rate, the effect of sodium, magnesium and calcium impurities on the electrical properties of silicon based films is also discussed. The growth rate and hydrogen content of silicon based thin films decrease, the dark conductivity at room temperature decreases, the conductance activation energy increases, and Guang Min becomes better. The optical band gap decreases with the increase of hydrogen content in Si-H form in silicon based films, and the hydrogen content in silicon based thin films decreases. In particular, hydrogen in the form of Si-H can improve the optoelectronic properties of silicon based thin films. Due to the entry of sodium, magnesium and calcium impurities, the Guang Min property of silicon thin films will be reduced, the dark conductivity will become larger, and the activation energy of conductance will become smaller.
【学位授予单位】：汕头大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.2

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