GOALI: Thermal-Capillary Analysis of the Horizontal Ribbon Growth of Solar Silicon via Finite-Element Process Models

GOALI：通过有限元过程模型对太阳能硅的水平带生长进行热毛细管分析

• 批准号: 0755030
• 负责人: Jeffrey Derby
• 金额: $ 30.71万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2013-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0755030&HistoricalAwards=false
• 关键词: GOALI; Thermal; Capillary; Analysis; Horizontal

CBET-0755030Derby Solar-grade, crystalline silicon is produced by a variety of techniques which melt and carefully re-solidify silicon via thermal transport processes. These processes typically involve an interesting trade-off: Methods that grow single crystals of silicon are expensive, but such material achieves the highest cell efficiencies. Lower-cost growth methods typically produce multi-crystalline material that results in cells of lower efficiency. A promising technology to grow single crystals of silicon at much lower costs, known as the horizontal ribbon growth (HRG) process, was put forth in the 70's and early 80's but was abandoned in favor of more traditional methods that were easier to develop. Accumulated advances in crystal growth modeling and understanding make it propitious to reconsider the HRG method for growing crystalline silicon for solar cells. If this process were successfully deployed, it could significantly reduce production costs for silicon substrate by dramatically increasing growth rates and by avoiding the costly kerf losses associated with cutting wafers from silicon ingots. In addition, HRG methods promise the growth of single-crystal material needed for solar cells of the highest efficiency, rather than multi-crystalline silicon currently produced by casting and vertical ribbon growth methods. A successful HRG process would be transformative by promoting simultaneous cost reductions and efficiency increases for silicon solar cells. The premise of the work proposed here is that the great potential of the horizontal ribbon growth method will not be realized until a more fundamental understanding of its mechanistic workings enables new progress in process development. Theoretical, thermal-capillary models will be developed and applied in conjunction with process experiments to assess the feasibility of the HRG process for the production of crystalline silicon for photovoltaic applications. These studies will allow for fundamental investigations of coupled heat transfer and interfacial processes (solidification and capillarity) in this crystal growth system.Intellectual merit of the proposed activity This work will develop and apply rigorous theoretical models to study the nonlinear interactions between thermal transport processes and interfacial phenomena that control silicon crystal production via the horizontal ribbon growth process. Of particular intellectual merit will be understanding the stability and dynamics of this system. Unlike vertical, meniscus-defined crystal growth processes that are inherently stable, the HRG process may be unstable, and its successful operation will likely rely on a thorough understanding of system design and control.Broader impacts resulting from the proposed activity This effort will advance discovery and understanding by training a graduate student in a multi-disciplinary and industrially relevant project. It will enhance infrastructure by promoting collaborations with industry. This work will directly impact process development at Ribbon Technology International, a company founded by Bleil, the originator of the horizontal ribbon growth (HRG) process. This interaction will leverage experimental observation with the theory conducted in this work. From a broader perspective, a successful HRG process could trigger a transformative enabling of current technology by simultaneously reducing silicon crystal production costs while improving solar cell efficiency. Dissemination activities will include an outreach program for the general public involving the Science Museum of Minnesota. This project is jointly funded by the Thermal Transport Processes (TTP) Program, of the Chemical, Bioengineering, Environmental, and Transport Systems (CBET) Division, by the Materials Processing & Manufacturing (MPM) Program, of the Civil, Mechanical, and Manufacturing Innovation (CMMI) Division, and by the Grant Opportunities for Academic Liaison with Industry (GOALI) Program, of the Industrial Innovation & Partnerships (IIP) Division, all within the Directorate for Engineering (ENG).

CBET-0755030Derby太阳能级，结晶硅是由多种技术生产的，这些技术通过热传输过程融化和仔细地重新固定硅。这些过程通常涉及一个有趣的权衡：生长硅单晶的方法很昂贵，但是这种材料达到了最高的细胞效率。低成本生长方法通常会产生多晶体材料，从而导致效率较低的细胞。在70年代和80年代初提出了一种以低得多的成本（称为水平色带生长（HRG）工艺）生长硅单晶的有前途的技术，但被放弃，而倾向于更易于开发的传统方法。晶体生长模型和理解的积累进展使得重新考虑用于生长太阳能电池的晶体硅的HRG方法是有利的。如果该过程成功地部署，则可以通过大幅提高生长速率并避免与硅锭的晶圆相关的昂贵的KERF损失来大大降低硅底物的生产成本。此外，HRG方法有望确保最高效率太阳能电池所需的单晶材料的生长，而不是目前通过铸造和垂直带状生长方法生产的多晶硅。成功的HRG过程将通过促进硅太阳能电池的同时降低成本降低和效率提高，这将是变化的。这里提出的工作的前提是，直到对其机械工作的更基本的理解能够在过程开发方面取得新的进展，水平色带增长方法的巨大潜力才能实现。理论上的热毛细管模型将与过程实验一起开发和应用，以评估HRG工艺生产晶体硅用于光伏应用的可行性。 These studies will allow for fundamental investigations of coupled heat transfer and interfacial processes (solidification and capillarity) in this crystal growth system.Intellectual merit of the proposed activity This work will develop and apply rigorous theoretical models to study the nonlinear interactions between thermal transport processes and interfacial phenomena that control silicon crystal production via the horizo​​ntal ribbon growth process.特别的知识优点将是理解该系统的稳定性和动态。与垂直不同的是固有稳定稳定的半月板定义的晶体生长过程，HRG过程可能不稳定，其成功的操作可能会依赖于对系统设计和控制的透彻理解。拟议活动所产生的行为影响，这项工作将通过在多学科和工业相关的项目中培训研究生。它将通过促进与行业的合作来增强基础架构。这项工作将直接影响由水平色带增长（HRG）过程的发起人Bleil创立的Ribbon Technology International的过程开发。这种相互作用将利用这项工作中进行的理论来利用实验观察。从更广泛的角度来看，成功的HRG过程可以通过同时降低硅晶体生产成本，同时提高太阳能电池效率，从而触发当前技术的变革性促进。传播活动将包括针对明尼苏达州科学博物馆的普通大众推广计划。 This project is jointly funded by the Thermal Transport Processes (TTP) Program, of the Chemical, Bioengineering, Environmental, and Transport Systems (CBET) Division, by the Materials Processing & Manufacturing (MPM) Program, of the Civil, Mechanical, and Manufacturing Innovation (CMMI) Division, and by the Grant Opportunities for Academic Liaison with Industry (GOALI) Program, of the Industrial Innovation & Partnerships (IIP) Division, all within the工程局（ENG）。