Application of closed field magnetron sputtering deposition in thin film photovoltaics
Application of closed field magnetron sputtering deposition in thin film photovoltaics
复制标题
闭场磁控溅射沉积在薄膜光伏中的应用
DOI：
10.1117/12.825257
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Gibson D
中科院分区：
文献类型：
--
作者：
Gibson D
薄膜太阳能电池技术是非常有前途的，使清洁和低成本的太阳能发电的各种应用。薄膜太阳能电池的高效率、柔韧性和轻量化优势，以及稳定的性能和潜在的低生产成本，进一步增强了它们对地面和空间应用的吸引力。薄膜太阳能电池的一个明显的制造优势是使用快速真空沉积方法，提供了降低制造成本所必需的高通量。然而，一个重要的先决条件是沉积技术的发展，该技术结合了在单个真空循环内沉积太阳能电池薄膜多层的能力，从而消除了使用非真空湿化学进行某些工艺步骤的要求。此外，工艺开发还需要提供低温加工和低应力多层薄膜结构，使光伏器件能够沉积在低成本的柔性聚合物或金属基板上。本文介绍了一种新的溅射工具策略，利用高等离子体密度（~10mA.cm-2）和低离子能量，从而降低了在柔性和固体基底上沉积的工艺温度和薄膜应力。该技术使用极性相反的磁控管来创造一个“封闭场”，在这个“封闭场”中，等离子体密度得到增强，而不需要施加高电压。设计了一种采用旋转垂直滚筒作为衬底载体和四个线性磁控管对称阵列的原型批处理系统。磁控管与PV堆中所需的每个薄膜的目标材料相匹配，包括CdTe吸收层、CdS缓冲层和后TCO触点。系统设计的细节将与已经从ITO薄膜中获得的光学、电学和计量数据一起提供。“封闭场”溅射技术不仅允许大规模批量系统设计，而且还可以配置为“在线”或“卷对卷”格式的大规模生产。
Thin film solar cell technology is highly promising to enable clean and low cost generation of solar electricity for various applications. The high efficiency, flexibility and lightweight advantages of thin film solar cells, together with stable performance and potentially low production costs, further enhance their attractiveness for both terrestrial and space applications. A distinct manufacturing advantage of thin film solar cells is the use of fast vacuum deposition methods, providing the high throughput essential to reduce manufacturing costs. However, an essential pre-requisite is the development of deposition techniques which combine capability to deposit the solar cell thin film multilayer preferably within a single vacuum cycle, removing the requirement for certain process steps to be carried out using non-vacuum wet chemistry. Moreover, process development is also needed to provide low temperature processing and low stress multilayer thin film structures which enable photovoltaic devices to be deposited on to low cost flexible polymer or metal substrates. In this paper a new sputtering tool strategy is introduced, utilising high plasma densities (~10mA.cm-2) and low ion energies, thereby lowering process temperature and film stress for deposition onto both flexible and solid substrates. The technique uses magnetrons of opposing magnetic polarity to create a "closed field" in which the plasma density is enhanced without the need for high applied voltages. A prototype batch system has been designed which employs a rotating vertical drum as the substrate carrier and a symmetrical array of four linear magnetrons. The magnetrons are fitted with target materials for each of the thin films required in the PV stack including the CdTe absorber layer, CdS buffer layer and the back TCO contact. Details of the system design will be provided together with optical, electrical and metrology data already obtained from ITO thin films. The "closed field" sputtering technology allows scale up not only for larger batch system designs but it is also configurable for "in-line" or "roll to roll" formats for large scale production.