以非晶矽吸雜法製作低成本之太陽能電池

Improving the efficiency of low-cost metallurgical silicon solar cells by amorphous Si gettering technique

許正彥(Jeng-Yan Shiu)

指導教授 ： 廖森茂

中原大學/工學院/電子工程研究所/碩士(2009年)

https://doi.org/10.6840/cycu200900877

摘要

本論文針對提純冶金級多晶矽(UMG-Si)基板進行去疵製程處理(Gettering process)，研製多晶矽太陽能電池，以期提升電性特性。
近年來，各國對於太陽能電池需求量增加，導致矽原料的不足，成本高居不下。本實驗以降低成本為考量，選擇在純度較低的提純冶金級多晶矽基板上，使用電漿式化學氣相沉積儀(PECVD)成長非晶矽薄膜(a-Si：H)，利用非晶矽薄膜經過熱處理之後產生的差排、缺陷，藉此吸附基板金屬雜質，以提高基板的電性特性。
分析方面，使用霍爾量測儀(Hall Measurement)量測去疵製程後的矽基板，探討遷移率改善情形；藉由二次離子質譜儀(SIMS)觀察基板金屬雜質在去疵前後的分布情形。接著採用此種基板製作太陽能電池。使用高溫擴散爐(Diffusion Furnace)在基板形成P-N Junction、電子槍蒸鍍機(E-gun Evaporator)製作正面電極、網版印刷技術(Screen-Printed)塗佈鋁膠(Al Paste)以製作背面電極，最後使用電漿式化學氣相沉積儀製作SiNx抗反射層。完成太陽能電池並量測轉換效率

關鍵字

太陽能電池 ； 非精矽 ； 去疵技術

並列摘要

This study investigated for upgraded metallurgical grade silicon (UMG-Si) substrates by gettering process and expected to improve the device’s electronic properties. After gettering process, we develops polycrystalline silicon solar cell by this UMG-Si substrates.
In recent years, the demand of solar cells was increasing in the world, which causes the deficiency of silicon feedstock and therefore makes the cost of silicon raw material remain high. So, the aim of this experiment is to reduce cost of material, low cost upgraded metallurgical grade silicon (UMG-Si) wafers will be used as the substrates and an epitaxial amorphous Si (a-Si：H) thin film will be grown thereon by Plasma-enhanced chemical vapor deposition(PECVD) . Loose structure of amorphous Si thin film has many cavities or dislocations that will trap the metal impurities by thermal annealing treatment. The gettering process could improve the electrical properties of UMG-Si substrate.
In analytical part, using Hall Measurement, we discuss the improvement of moility after gettering process. In order to understand the metallic impurities characteristic of the substrate which are trapped, we exhibited the metal impurities distribution of substrate by secondary ion mass spectroscopy(SIMS). Then we made solar cell by this substrate. Forming P-N Junction by high temperature diffusion furnace chamber、fabricating front side electrode by E-gun evaporator、rear side electrode by Al paste screen printing、making anti-reflection coating(ARC) by PECVD. We finish solar cell and measure the conversion efficiency.

並列關鍵字

a-Si:H ； gettering process ； solar cell

參考文獻

[2] Khattak, C.P., Joyce, D.B., Schmid, F., “Upgrading metallurgical grade (MG) silicon for use as solar gradefeedstock,” Photovoltaic Specialists Conference, 2000. Conference Record of the Twenty-Eighth IEEE

[3] S. Coffa, J. M. Poate, D. C. Jacobson, A. Polman “Impurity trapping and gettering in amorphous silicon,” Appl. Phys. Lett. 58 (1991), 2916

[4] Mitsuo Fukuda, “Optical Semiconductor Devices,” John Wiley & Sons, Inc., p220-221

[5] Dieter K. Schroder, “Semiconductor material and device characterization 2th,” John wiley & Sons, Inc., p.209

[8] W. Schroter, M. Seibt, and D. Gilles, in “Electronic Structure and Properties of Semiconductors,” of Materials Science and Technology: AComprehensive Treafmenf, edited by R. W. Cahn, P. Haasen, and E. J. Kramer (VCH, New York, lYYl), Vol.4, p.576.