Research for the Relationship between Temperature Distribution and Process Settings of Unidirectional Solidification Poly-Silicon Ingots

• Main Authors: I-Hsuan Wang, 王奕軒
• Other Authors: Shuang-Shii Lian
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/12495675139750812851

碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 96 === The photovoltaic industry has been generated electric power more than 150 MW. To know well about polycrystalline silicon growth method would lead us to pioneer. Hence, many scientists and corporations are interested in studying of polycrystalline silicon (poly-Si) ingot growth, crystal structure, orientation, growth rate, and grain size. For achieving a high efficiency of poly-Si solar cell, it is necessary to optimize the structural properties of poly-Si. Therefore, it is important to simulate the temperature distribution and reaction field of vacuum induction furnace for the industrial advancement. The main goal of this paper is to simulate the temperature distribution of the vacuum induction furnace during unidirectional solidification process. There are two main parts in this paper. First, we develop a COMSOL finite element model of polycrystalline silicon melting between a harmonic electromagnetic and transient thermal phenomena analysis, factors such as the setting of crucibles and the conditions of crucibles. Second part is the experiment verification of poly-silicon ingot. This paper compares the results of the calculated temperature distributions with the measured temperatures and analyzes the quality of the ingot, such as its macrostructure, microstructure, and composition. There is 2% difference between the modeling and measured temperatures. Finally, microstructures using three different pulling speeds were observed by optic microscope. The microstructure of the ingot using slowest pulling speed (2mm/min) has best result for solar cell.